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5
The ESRD Patient Population: Special Groups

Several segments of the ESRD population deserve special consideration: pediatric, elderly, diabetic, hypertensive, and minority patients. In all but the pediatric group, renal failure risk is higher than that among the general population.

PEDIATRIC PATIENTS

Pediatric ESRD patients, ranging in age from birth to 20 years, are special patients with very special needs. Their physical and emotional growth relative to their age is often delayed as a consequence of their chronic illness. Indeed, the primary difference between the child and the adult ESRD patient lies in the child's needs to grow and develop, both physically and mentally, and in how these needs interact with treatment.

In this section, the incidence, prevalence, and survival of pediatric ESRD patients from 1978 to 1987 are described. Also discussed are morbidity, prevention of ESRD, access to treatment, and the special needs and problems of the pediatric patients, their families, and their providers.

The absolute numbers of incident and prevalent pediatric ESRD patients for 1978 and 1987 are shown in Table 5-1. During this period, the incidence of treated ESRD among infants and preschool children under age 5 years tripled, from 37 to 120; children in the 5-to 9-year age group increased 36 percent, from 81 to 110 patients; and incidence among older children was steady during this period (P.W. Eggers, S. Alexander, and J.E. Lewy, unpublished data, 1990).

As in the adult population, ESRD incidence is greater among males than among females; in particular, it is almost twofold higher among male infants. In contrast to the adult population, black children and white children



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Kidney Failure and the Federal Government 5 The ESRD Patient Population: Special Groups Several segments of the ESRD population deserve special consideration: pediatric, elderly, diabetic, hypertensive, and minority patients. In all but the pediatric group, renal failure risk is higher than that among the general population. PEDIATRIC PATIENTS Pediatric ESRD patients, ranging in age from birth to 20 years, are special patients with very special needs. Their physical and emotional growth relative to their age is often delayed as a consequence of their chronic illness. Indeed, the primary difference between the child and the adult ESRD patient lies in the child's needs to grow and develop, both physically and mentally, and in how these needs interact with treatment. In this section, the incidence, prevalence, and survival of pediatric ESRD patients from 1978 to 1987 are described. Also discussed are morbidity, prevention of ESRD, access to treatment, and the special needs and problems of the pediatric patients, their families, and their providers. The absolute numbers of incident and prevalent pediatric ESRD patients for 1978 and 1987 are shown in Table 5-1. During this period, the incidence of treated ESRD among infants and preschool children under age 5 years tripled, from 37 to 120; children in the 5-to 9-year age group increased 36 percent, from 81 to 110 patients; and incidence among older children was steady during this period (P.W. Eggers, S. Alexander, and J.E. Lewy, unpublished data, 1990). As in the adult population, ESRD incidence is greater among males than among females; in particular, it is almost twofold higher among male infants. In contrast to the adult population, black children and white children

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Kidney Failure and the Federal Government TABLE 5-1 Incidence and Prevalence of Pediatric End-Stage Renal Disease (ESRD) Patients, 1978 and 1987   Age Group (years)   0–1 1–4 5–9 10–14 15–19 All Incidence             1978 12 25 81 208 428 754 1987 52 68 110 194 470 894 Increase (%) 333 172 36 -5 9 19 Prevalence             1978 a 43 195 546 1,348 2,132 1987 a 262 536 930 2,203 3,931 Increase (%) a 446 175 70 63 84 a Excluded because of small numbers. SOURCE: P.W. Eggers (Health Care Financing Administration), S.R. Alexander (Southwestern Medical Center, University of Texas, Dallas), and J.E. Lewy (Tulane University School of Medicine, New Orleans, Louisiana), unpublished data, 1990. have similar incidence rates until their early teens, when incidence rates among blacks begin to exceed those among whites. By ages 16 to 18 years, rates among blacks are about twice those among whites. The increasing incidence in younger age groups combined with improved survival resulted in nearly a twofold increase in prevalence of pediatric patients between 1978 and 1987 (Table 5-1). In 1988, there were 833 new pediatric patients in the Medicare ESRD program, or 2.3 percent of all new patients; prevalence was 4,069, or 2.8 percent of all patients. Many quality-of-life factors are unique to pediatric patients. These include growth retardation, delayed pubertal development, transfusion-dependent anemia, bone and neurologic abnormalities, as well as psychosocial and educational problems. The burdens common to all ESRD patients are often greater for pediatric patients. The increased incidence and survival of infants and preschool children with ESRD leads to increased comorbidities and treatment problems in the older pediatric population. Major physical problems, such as bone deformities and inhibited growth, are more severe in infants and young children than in those who acquire ESRD at older ages. Transplantation is the preferred treatment for almost all children; the needs for physical growth and pubertal development are better met through transplantation than dialysis. Table 5-2 shows the change between 1978 and

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Kidney Failure and the Federal Government 1987 in the proportion of pediatric patients who had a functioning transplant during those years. Recently, however, two factors have adversely affected the transplantation rate among children: (1) the limited number of available kidneys despite the increased number of acceptable recipients (Chapter 8); and (2) a UNOS policy in 1988 and 1989, since revised, of allocating grafts to patients on the basis of time on a transplant waiting list. Younger children are adversely affected by these factors, since growth is a critical problem and more constrained by dialysis than transplantation. Transplantation from living related donors is sometimes undertaken as a way to ensure rapid resumption of growth in these children, since the waiting time for cadaver transplants is often prolonged. The recent availability of recombinant growth hormone may alleviate the problem of growth somewhat in young dialysis patients. Except among infants, survival rates are higher for pediatric ESRD patients than for adults. These rates have been improving progressively among children over time, especially among the younger age groups (Table 5-3). These survival trends are true for dialysis as well as transplant patients, but average survival rates for patients with transplants are higher than for those treated with dialysis. How much of the difference is due to patient selection and timing of the treatment (for example, preemptive transplantation) versus direct advantage of the treatment is not known. Contributing to this has been an increase in graft survival over time, a factor that has been most important for the successful rehabilitation of pediatric patients. In addition, survival for transplant patients differs by source of graft: survival is greater for patients receiving kidneys from living related donors than from cadaver donors. Many physical problems affect ESRD pediatric patients uniquely or more severely than they affect adult patients (Fine, 1990). Bone disease may limit ambulatory activities of pediatric patients, including school attendance. TABLE 5-2 Percentage of Pediatric End-Stage Renal Disease (ESRD) Patients with Functioning Graft, 1978 and 1987   Age Group (years)   0–1 1–4 5–9 10–14 15–19 All 1978 0 19 37 34 29 30 1987 7 48 62 56 54 55 NOTE: As of December 31 of the given year. SOURCE: P.W. Eggers (Health Care Financing Administration), S.R. Alexander (Southwestern Medical Center, University of Texas, Dallas), J.E. Lewy (Tulane School of Medicine, New Orleans, Louisiana), unpublished data, 1990.

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Kidney Failure and the Federal Government TABLE 5-3 Pediatric End-Stage Renal Disease (ESRD) Patient Survival (percent) at One Year by Year of Incidence and Age Group, 1978 and 1987 Age Group (years) 1978 1987 Under 1 a 83.9 1–4 76.0 98.5 5–9 93.8 99.1 10–14 96.7 99.0 15–19 95.5 96.5 NOTE: Includes dialysis and transplant patients who have survived the first 90 days of end-stage renal disease (ESRD) treatment. Only 9 months of time at risk are included in this period, which ends at one year after ESRD treatment initiation. a Excluded because of small numbers. SOURCE: USRDS, 1989, Table D-5. Associated abnormalities resulting from disturbed calcium/phosphorus metabolism include visual abnormalities, growth delay or growth failure, poor calcification of bone, and severe overactivity of the parathyroid gland. Neurologic abnormalities may include seizures, which occur at a greater frequency in the pediatric than in the adult ESRD patient. Of particular importance in younger children is growth retardation. Significant psychosocial problems may arise among pediatric ESRD patients as a result of their short stature. Furthermore, delayed pubertal development limits psychosocial and psychosexual development of adolescent patients with ESRD. Psychosocial problems among adolescent transplant patients are also exacerbated by the side effects of immunosuppressive medications, such as corticosteroids and cyclosporine. A full, rounded face (Cushingoid facies), acne, and obesity may result from corticosteroid therapy. Hirsutism (excessive hair) may result from cyclosporine treatment of transplant recipients. The negative psychological reaction to these side effects may result in noncompliance with immunosuppressive drug treatment and may lead to graft failure. Other treatments have important side effects on pediatric patients. Various antihypertensive medications may adversely influence the patient's level of activity, academic achievement, and sleep patterns. Severe anemia greatly affects the pediatric patient because of the resulting fatigue, apathy, and anorexia that negatively affect social and educational activities. This problem is now helped by the use of erythropoietin. Surgical interventions present special problems for young patients. Multiple surgical scars resulting from repetitive peritoneal and/or vascular access, bilateral nephrectomy, and one or more renal transplants negatively affect

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Kidney Failure and the Federal Government the pediatric patient's psychosocial development and sense of well-being. Multiple hospitalizations may produce fears in the younger child and interfere with schooling of the older patient. Although many of the above problems are common to all ESRD patients, the pediatric ESRD patient must cope with the problems of growth and development as well as the challenges of ESRD treatment. The pediatric ESRD patient requires more time and attention from physicians, nurses, social workers, nutritionists, psychologists, and other health care professionals. They and their families are also very sensitive to limitations on access to treatment and financial resources. The special needs of infants, children, and adolescents with ESRD require a multidisciplinary approach to care. This calls for the availability of specially trained pediatric nephrologists, renal nursing specialists, renal nutritionists, social workers, psychologists, and, often, special teachers or vocational rehabilitation counselors. Pediatric urologists and surgeons are also required. There is a shortage, however, of trained personnel to deal with pediatric ESRD patients (Fine, 1990). Specialized pediatric renal failure centers are necessary for the training of the nephrologists, nutritionists, social workers, and nursing personnel. The availability of these centers is essential to provide appropriate supervision of pediatric patients and to provide consultation for children and their families and physicians who reside in rural areas that are not in close proximity to the children's centers and who must use a facility that is closer to the patient's home. Such supervision and consultation may ensure that optimal care is provided to pediatric patients regardless of their residence. Children also confront problems related to drug therapy. They are often excluded from testing for the safety and efficacy of new pharmaceuticals. Certain drugs, therefore, either are unavailable to children or must be administered without supporting clinical trial data. Multicenter collaborative studies of new therapies are needed so that enough pediatric subjects will be available to evaluate treatment effects in that population. The pediatric ESRD population is increasing over time, and many of their problems remain unresolved. Many preventable medical, psychosocial, and educational complications associated with ESRD in the pediatric patient are related to the patient's eligibility for Medicare coverage. The committee's recommendations that Medicare ESRD coverage be extended to all U.S. citizens, independent of Social Security status (Chapter 7), and that HCFA establish special reimbursement rates for children with ESRD (Chapter 11) are steps that will help alleviate these problems. ELDERLY ESRD PATIENTS Medicare was established in 1965 to provide medical care to those 65 years of age and over. At the outset, Medicare covered established medical

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Kidney Failure and the Federal Government services, and neither dialysis nor kidney transplantation was recognized as an established service. After the 1967 Report of the Committee on Chronic Kidney Disease, dialysis and transplantation were basically elevated from ''experimental'' to "established" treatments (Rettig, 1981). However, few elderly patients were dialyzed in the late 1960s because advanced age was considered a contraindication for renal replacement therapy. In 1971, Medicare received several inquiries about dialysis coverage for the elderly but had not clarified its policies regarding ESRD. Neither patients nor physicians knew that the elderly were potentially covered by Medicare for dialysis under the 1965 statute. The 1972 kidney entitlement, however, created a Medicare benefit for those under 65. By definition, a Medicare benefit could not be made available to the non-elderly and remain unavailable to the elderly. Hence, the 1972 statute sanctioned Medicare financing for elderly ESRD patients. The earlier orientation against treating the elderly is reflected in the fact that those over 65 years of age accounted for only 5 percent of the total enrollment in 1974 and 11 percent in 1975, but climbed to 18 percent in 1978 (Rettig and Marks, 1980). By 1988, 38 percent of incident (new) ESRD patients, or 13,866, and 27 percent of prevalent (all) patients, or 39,383, were over age 65. Thus the incidence of treated renal failure is now much higher among the elderly than among the general population. In 1988, it was nearly 500 per million population for those over age 65 compared to 147 per million for the general population (USRDS, 1990). The proportion of elderly patients among all those being treated for ESRD continues to increase, perhaps in part because decreasing general mortality from other conditions, such as cardiovascular diseases, enables more patients to reach renal failure. Projections (see Chapter 4) indicate that the elderly will account for nearly half of new Medicare ESRD patients by the year 2000. The growth among the very old ESRD population is even more striking. Among those 85 and older, new ESRD patients increased from 65 in 1978 to 580 in 1988, for an average annual growth rate of 18 percent. Changes in incidence over time for various age groups are shown in Table 5-4. The primary diagnoses leading to renal failure among treated elderly ESRD patients have changed over time (IOM, 1990). Diabetes and hypertension have accounted for an increasing proportion of cases. Diagnostic data are unavailable for the elderly in the early 1970s. In 1978, among new elderly ESRD patients with a specified diagnosis leading to renal failure, 16 percent were diabetic and 38 percent were hypertensive. These proportions had increased to 29 and 42 percent, respectively, by 1988 (IOM, 1990). Glomerulonephritis account for a steady 17 to 18 percent of new elderly patients.1 Similar trends hold for prevalent patients, except that diabetic patients are a lesser percentage of the prevalent population, compared to new patients, due to their higher mortality rate.

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Kidney Failure and the Federal Government TABLE 5-4 New End-Stage Renal Disease (ESRD) Patients in 1978 and 1988, by Age Group Age Group(years) 1978 1988 % Increase 0–64 11,258 22,294 98 65–75 2,838 8,805 210 75–86 745 4,530 508 85 and up 54 531 883   SOURCE: USRDS, 1990. Elderly patients generally arrive at permanent kidney failure with more comorbidity than their younger counterparts, including unstable hemodynamics, vascular disease, and impaired function. In particular, elderly diabetics exhibit the various comorbidities typical of that disease, including visual problems, neuropathy, and amputations. Treatment modality is highly age dependent, as is shown in Figure 5-1. More young people than elderly receive transplants, the primary treatment modality for the elderly ESRD patient being hemodialysis. On December 31, 1988, elderly ESRD patients were distributed among treatment modalities in the following way: 82 percent in-center hemodialysis, 2 percent home dialysis, 9 percent peritoneal dialysis, 2 percent transplant, and 5 percent other or unknown (USRDS, 1990). Adjusted mortality of elderly patient groups, although high, appears quite stable during the 1980s except for an increase between the 1982 and 1983 incidence cohorts (IOM, 1990; USRDS, 1990). Most of this increase is eliminated by adjusting for age and primary diagnosis, but a small increase in mortality still remains in some groups of patients after adjustment (USRDS, 1990). Most reports indicate stable adjusted mortality rates since the mid-1980s (Eggers, 1990; Sehgal et al., 1990; USRDS, 1990). A stable mortality despite an increasing proportion of very elderly and of underlying conditions such as diabetes among the elderly patients may reflect increasing physician and provider experience over time in treating a more vulnerable patient population. The leading causes of death among elderly ESRD patients are cardiac arrest, myocardial infarction, and withdrawal from treatment. In contrast to the experience among younger ESRD patient groups, withdrawal from dialysis is common among elderly ESRD patients, accounting for over 10 percent of all deaths of ESRD patients over 65 (USRDS, 1990). Patients or their families, in concert with physicians, withdraw because they decide that the burdens of treatment and the reduced quality of life outweigh the benefits of continued survival. (See Chapter 3.)

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Kidney Failure and the Federal Government FIGURE 5-1 ESRD Patients: Treatment Modality by Age Group, 1988 NOTE: Excludes small numbers of non-center dialysis patients. SOURCE: USRDS, 1989. The elderly ESRD patient population has increased in number, average age, comorbidities, and special problems in the past decade. These changes are expected to continue throughout the 1990s. The treatment needs of these patients will challenge clinicians in the years ahead to a greater extent than they have to date. DIABETIC PATIENTS Diabetes mellitus as a cause of ESRD has increased substantially in the past two decades. During the 1960s and early 1970s, diabetes was generally a reason for not treating ESRD patients. In the 1970s, diabetic patients were a small proportion of total ESRD patients (Table 5-5). By 1983, however, diabetic kidney disease had become the most frequent diagnosis among patients entering the Medicare ESRD program. Clinical experience in the late 1970s and the 1980s had shown that ESRD patients with a primary diagnosis of diabetes could benefit from renal replacement therapy. Simultaneously, improvements in the treatment of diabetes have contributed to decreased mortality from cardiovascular diseases. This has led to longer life spans and increased chance of renal failure later in life. In 1988,

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Kidney Failure and the Federal Government TABLE 5-5 Patients with Diabetic Kidney Disease as a Percentage of Total End-Stage Renal Disease (ESRD) Patients, by Age Group Age Group (years) 1972–76a 1983b 1988b 1–19 0.5 0.5 0.7 20–39 5.6 14.0 18.9 40–49 4.7 13.6 21.6 50–59 6.5 15.2 24.1 60+ 6.9 13.5 21.9 TOTAL 5.0 13.6 20.0 a Approximate, dialysis patients only. b Includes dialysis as well as transplantation patients. In 1983, one-third of diagnoses were reported as missing/unknown; in 1988, one-fifth were missing/unknown. Therefore, the percentages of diabetic patients for 1983 and 1988 are higher than presented above. SOURCES: Research Triangle Institute, 1976; HCFA, 1990. diabetics accounted for 27 percent (or 11,034) of new ESRD patients and 20 percent (or 29,937) of prevalent patients (USRDS, 1990). The age, gender, and racial distributions of new diabetic ESRD patients have been changing over time. Each year a greater proportion of these patients are elderly, as is true for the ESRD population as a whole. In 1982, the median age of a new diabetic ESRD patient was about 55 years, with 23 percent over age 65 and 11 percent over age 75; in 1988, the median age was 59, with 34 percent over age 65 and 18 percent over age 75. Incidence of diabetic ESRD differs by race. Rates are higher among blacks and Native Americans than among whites, and higher among Hispanics than among non-Hispanic whites. In a study of racial disparities in Michigan, after adjustment for the higher prevalence of diabetes among blacks, the incidence of diabetic ESRD was 2.6-fold higher among blacks than among whites (Cowie et al., 1989). Incidence of diabetic patients also differs by gender. Among whites, rates are higher among men; by contrast, rates among blacks and Native Americans are higher among women (USRDS, 1990). Incidence of ESRD differs dramatically as a function of type of diabetes. Although patients with insulin-independent diabetes mellitus (IDDM) constitute only 5 to 10 percent of all diabetics, they account for 40 percent or more of renal failure due to diabetes (Hawthorne, 1990; Rettig and Teutsch, 1990). The relative risk of renal failure appears to be 10 to 15 times greater from IDDM than from non-insulin-dependent diabetes mellitus (NIDDM). There are racial differences in the type of diabetes leading to ESRD. In Michigan, 77 percent of black diabetic ESRD patients had NIDDM, whereas 58 percent of white diabetic ESRD patients had IDDM (Cowie et al., 1989).

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Kidney Failure and the Federal Government Genetic factors also play a role. Familial susceptibility to diabetic nephropathy (NIDDM) has been shown among the Pima Indians (Pettitt and Saad, 1988), as well as among patients with IDDM (Seaquist et al., 1989). Like incidence, prevalence has increased substantially since 1973, although HCFA data for primary diagnosis are highly incomplete before 1982. Between 1982 and 1988, however, there has been a threefold increase in prevalent diabetic ESRD patients, from 9,913 to 29,937 (USRDS, 1990). Diabetic ESRD patients have higher adjusted mortality rates than the other major diagnostic groups—glomerulonephritis and hypertension. During the 1980s, however, mortality rates of diabetic ESRD patients, when controlled for age, gender, and race, decreased slightly for patients on dialysis or with transplants (USRDS, 1990) in spite of substantial increases in incident patients and, presumably, in patient complexity. This suggests that growing clinical experience with this patient segment may have reduced the risk of mortality. Most patients with diabetic ESRD die of coronary heart disease within 5 years of onset of ESRD treatment (Hawthorne, 1990). In addition to higher mortality rates, diabetic ESRD patients have more comorbidities than the other major diagnostic groups. Major comorbidities include blindness, peripheral neuritis, and vascular disease. Hypertension is present in two out of three patients (Hawthorne, 1990). The increased severity of illness of diabetic ESRD patients leads to increased hospitalization and higher overall medical costs (Smith et al., 1989). Knowledge of the risk factors for the development of diabetic nephropathy is critical in determining points of intervention. Major risk factors include hyperglycemia, hypertension, macrovascular disease, familial associations, race, age, and type and duration of diabetes. Some risk factors for development of ESRD in diabetics may be susceptible to intervention. In longitudinal studies, poor glucose control is a strong predictor of development of clinical diabetic nephropathy. Thus, strict glucose control may be of value in primary prevention of early diabetic nephropathy and possibly slowing or reversing early nephropathy (Hawthorne, 1990). Hypertension is an important predictor and possible cause of diabetic nephropathy. The appearance of hypertension in a diabetic patient with previously normal blood pressure may be the first sign of renal disease (Selby et al., 1990). Blood pressure monitoring and control is indicated for all diabetic patients (Working Group on Hypertension in Diabetes, 1987). Albuminuria screening is under study as a test for the earliest phase of diabetic kidney disease; early recognition would permit institution of treatment to prevent or slow development of ESRD (Bennett, 1989; Mogensen and Christiansen, 1984; Viberti et al., 1982). In addition, some research suggests that protein restriction may slow or halt renal decline (Cohen et al., 1986; Wiseman et al., 1987). Hence, the American Diabetes Associa-

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Kidney Failure and the Federal Government tion has recommended that diabetics restrict their dietary intake of protein (American Diabetes Association, 1986). The rapid increase of diabetics treated for renal failure underlines the urgent need to understand the etiologies of this disease process as well as potential interventions. The development of screening methods to assess renal function of diabetics and detect the early stages of diabetic nephrology should be pursued. In addition, measures to distinguish between IDDM and NIDDM as well as to classify comorbidities, including hypertension and cardiovascular diseases, should be developed and incorporated in ERSD data systems at HCFA and the USRDS. HYPERTENSIVE PATIENTS The incidence and prevalence of treated hypertensive ESRD has increased continually since the Medicare ESRD program was initiated. In 1974, 13.5 percent of the new patients (less than 1,000) entered the program with the diagnosis of hypertensive ESRD (Eggers et al., 1984). By 1988, 27 percent of new patients, or 9,647, carried this diagnosis; the prevalence of hypertensive patients was 21 percent, or 30,517 patients (USRDS, 1990). Hypertension in the United States A substantial proportion of the U.S. population has hypertension. According to the Second National Health and Nutrition Examination Survey (NHANES II), conducted during 1976–80 (NCHS, 1986), an estimated 18 percent of U.S. adults (about 25 million) had "definite hypertension," defined as a systolic blood pressure (SBP) at least 160 mmHg and/or diastolic blood pressure (DBP) at least 95 mmHg, and/or taking antihypertensive medication. Under a more liberal definition of hypertension (DBP at least 90 mmHg, SBP at least 140 mmHg, and/or medicated), hypertensives comprised nearly 30 percent of (or about 40 million) Americans. Prevalence of hypertension increases with age; men have higher rates at younger ages, women at older ages. Blacks have higher rates than whites; the prevalence of definite hypertension for blacks and whites, by age group and gender, in the NHANES II data set is shown in Table 5-6. Between 1960 and 1980, the prevalence of definite hypertension among black adults decreased from 33.6 to 28.6 percent; no similar decline was observed among whites (NCHS, 1986). The proportion of hypertensives taking antihypertensive medications increased from 30 to 45 percent and the proportion of those whose hypertension was controlled by medication increased from 39 to 52 percent. The prevalence of hypertension in the United States

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Kidney Failure and the Federal Government pressure of 90–104 mmHg, incidence of renal disease was 16 per 1,000 patients; for those with blood pressure of 105–114 mmHg, incidence was 35 per 1,000; for those with blood pressure above 115 mmHg, incidence was 58 per 1,000. These results, although not free of confounding factors, suggest an effect of blood pressure on development of renal disease. Klag (1990) used data from the HDFP study and from NCHS hypertension prevalence summaries to estimate the number of people expected to develop hypertensive renal disease, defined by the HDFP study, between 1990 and 1995. For the three diastolic blood pressure groups 90–104 mmHg, 105–114 mmHg, and greater than 115 mmHg, he calculated approximately 320,000, 80,000, and 47,000 new cases, respectively. According to his calculations, two-thirds of these new renal disease cases were expected in hypertensive patients with lowest blood pressure (DBP 90–104 mmHg). Klag concluded that although the risk of developing hypercreatininemia is greater at the highest levels of blood pressure, most cases of renal dysfunction will develop in those hypertensives with the mildest elevations of blood pressure. This seeming paradox occurs because the number of persons with mild diastolic hypertension is much greater than the number in the higher strata of blood pressure. Thus, therapeutic and preventive interventions directed at severe hypertensives can, at the most, prevent only a minority of renal disease cases. To substantially reduce the national burden of hypertension-related kidney disease, intervention strategies must include the large number of people with mild hypertension (Klag, 1990, pp. 22–23). The relationship between hypertension, the decline of renal function, and the development of ESRD must be clarified for various levels of blood pressure. The effect of control of blood pressure, hyperlipidemia, and other cardiovascular disease risk factors on ESRD incidence, morbidity, and mortality also should be evaluated. In addition, high priority should be given to evaluating the causes of excess hypertensive ESRD among blacks. MINORITY PATIENTS Following the 1972 kidney entitlement, different patterns of treated ESRD have appeared among racial and ethnic groups (Feldman, 1990). HCFA PMMIS data are used to present the basic epidemiology, including incidence, prevalence, and survival patterns, and variability in outcomes of treatment modalities between groups. The relative risk of developing ESRD is several times higher among blacks, Hispanics, and Native Americans than among whites, possibly because of physiologic heterogeneity of the racial and ethnic groups as well as differential access to preventive care. In 1988, nonwhite patients comprised 33 percent of incident (or 11,704) and prevalent (or 48,730) patients. The incidence of Medicare ESRD patients of all races has increased over

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Kidney Failure and the Federal Government the years. Between 1978 and 1988, the average yearly rate of increase in incidence was 10.1 percent among blacks compared with 8.9 percent among whites. Between 1981 and 1988, the average yearly rates of increase in new Medicare ESRD patients among Native Americans and Asians/Pacific Islanders were 16.6 percent and 26.2 percent, respectively.3 Estimated average yearly rate of increase for Hispanics, based on a sample of 9,690 Medicare patients with Hispanic surnames, was 12.7 percent (IOM, 1990). Age-and sex-adjusted treated ESRD incidence rates are four times greater for blacks and Native Americans (404 and 109 per million population in 1988, respectively) than for whites (109 per million) (USRDS, 1990). Rates among Asians/Pacific Islanders are closest to those of whites. Hispanics in Texas have threefold higher rates than non-Hispanic whites (Pugh et al., 1988). The age, gender, and primary disease distributions of incident patients differ considerably among races. Blacks and Native Americans, on average, experience ESRD at an earlier age than whites. Consequently, the age distributions between these groups are substantially different. The pattern for Asians/Pacific Islanders is closer to that of whites. The distribution, by age, of 1988 incident patients is shown in Figure 5-2. By race and gender, incidence rates among white men are 1.3–1.4 times higher than among women. Incidence rates among black men are slightly FIGURE 5-2 Age Distribution of New ESRD Patients, by Race, 1988 SOURCE: HCFA, 1990.

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Kidney Failure and the Federal Government FIGURE 5-3 Distribution of Primary Diagnosis Leading to ESRD, by Race, 1986–88 SOURCE: HCFA, 1990. higher than among women overall, but there is considerable variation by disease leading to ESRD: women have higher rates for diabetes and men have higher rates for hypertension and glomerulonephritis. Among Native Americans, Asians/Pacific Islanders, and Hispanics, men have a slightly higher risk than women (IOM, 1990; USRDS, 1990). As shown in Figure 5-3, primary diagnosis of cause of ESRD differs considerably among races. Hypertension is the predominant diagnosis among blacks; diabetes among whites, Native Americans and Hispanics; and glomerulonephritis among Asians/Pacific Islanders. Although Native American tribes are aggregated in the above data, they vary greatly in the incidence rates of treated ESRD across geographic and tribal boundaries. The Navajo, the largest Native American tribe, showed age-adjusted ESRD incidence rates four times those of whites between 1976 and 1980 (Gardner et al., 1984). Diabetes accounted for 50 percent of new patients, and the incidence rate of diabetic ESRD was 9.6 times that of whites. The Pima Indians of south central Arizona have one of the world's highest incidence rates of NIDDM, with an age-and gender-adjusted rate of 27 per 1,000 population, approximately 19 times the rate among whites (Knowler et al., 1978; Rate et al., 1983). Among Pima Indians with diabetes, the incidence of ESRD has been estimated to be as high as 21,400 per million leading to a treated diabetic ESRD rate of 960 per million (Kunzelman

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Kidney Failure and the Federal Government et al., 1989). The Zuni Indians, a small, ethnically homogeneous tribe of western New Mexico, had one of the highest reported ESRD incidence rates of any Native American group (Pasinski and Pasinski, 1987); between 1978 and 1985, it averaged 11 times that reported for whites. Glomerulonephritis was identified as a cause of 40 percent of new Zuni ESRD patients between 1973 and 1983. Although data on Hispanics are not systematically collected, Pugh and colleagues (1988) report that Mexican Americans had from 2.4 to 3.2 times higher rates of treated ESRD than non-Hispanic whites. Using data from the Texas Kidney Health Program and the 1980 U.S. census, they calculated 3-year average incidence rates of treated ESRD among Mexican Americans, blacks, and non-Hispanic whites between 1978 and 1984. Mexican Americans had 4.5 to 6.6 times the rate of diabetic ESRD among whites and 1.2 to 1.9 times the rate among blacks. Among Mexican Americans (Pugh et al., 1988) and U.S. Hispanics (IOM, 1990), diabetes is the primary diagnosis leading to ESRD. This high rate of diabetic ESRD is partly explained by the increased prevalence of diabetes mellitus: NIDDM is estimated to be about three times greater among Mexican Americans than among non-Hispanic whites (Stern et al., 1984). In addition, rates of hypertensive and glomerulonephritis-related ESRD are higher among Mexican Americans than among non-Hispanic whites. Among blacks, rates of hypertension and hypertensive ESRD are considerably higher than among whites. In the NHANES, the age-adjusted prevalence of hypertension was 28 percent and 40 percent among black men and women, respectively, compared to 21.5 percent and 20 percent among white men and women (Rowland and Roberts, 1982). However, the prevalence of hypertension was higher among whites and blacks having an annual household income below $20,000 (NCHS, 1990). Since a greater proportion of blacks fall into the lower income groups, economic disadvantage probably contributes to this racial difference in rates of hypertension. Once hypertension has developed, blacks have a higher risk of developing ESRD compared to whites (Shulman et al., 1989). Population-based studies have shown that hypertensive blacks have a five-to eightfold risk of developing ESRD compared to hypertensive whites (McClellan et al., 1988; USRDS, 1990). For individuals in their thirties and forties, the risk may be as much as 20 times higher among blacks than among whites (USRDS, 1990). The high risk of hypertensive ESRD among blacks suggests that blacks may have an elevated susceptibility to renal damage due to hypertension. Both diabetes and diabetes-related ESRD are also more common among blacks than among whites. Age-adjusted estimates of the prevalence of diabetes mellitus showed a 36 percent higher rate among blacks than among whites during 1985–87 (NCHS, 1987). Age-adjusted 1988 ESRD incidence rates were reported to be 1,094 and

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Kidney Failure and the Federal Government FIGURE 5-4 ESRD Patients, by Race, 1978–88 NOTE: As of December 31. SOURCE: USRDS, 1990. 1,306 per 10 million black men and women, respectively, compared to 369 and 315 among white men and women (USRDS, 1990). As expected from racial patterns in incidence, the prevalence rates for treated ESRD are considerably higher among blacks and Native Americans than among whites; the rates for Asians/Pacific Islanders and whites are similar. Total numbers of patients on December 31 of each year have increased for all racial groups (Figure 5-4). The mode of treatment of ESRD patients differs by racial group. In-center hemodialysis is the principal treatment for all races, but more so for blacks than for whites. Compared to whites, the proportion of blacks with a functioning renal transplant has been consistently smaller, and this gap has grown slowly over time (see Chapter 8). Table 5-8 shows black/white differences in treatment mode for 1980, 1984, and 1988. The 1-, 2-, and 5-year survival rates of nonwhite dialysis patients have been consistently higher than those of white patients. Table 5-9 shows these survival rates over time. Among transplant patients, black patients have lower survival than whites and other nonwhites. Between 1981 and 1983, the overall age-adjusted mortality rate from renal failure for Native Americans was 2.6 times the corresponding rate for all Americans. Several areas within the Indian Health Service (Aberdeen, South Dakota; Tucson, Arizona; Phoenix, Arizona) experienced mortality

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Kidney Failure and the Federal Government TABLE 5-8 End-Stage Renal Disease (ESRD) Treatment Modalities (percent) for Blacks and Whites on December 31, 1980, 1984, and 1988   1980 1984 1988 Modality Blacks Whites Blacks Whites Blacks Whites Functioning allograft 6.5 13.4 10.0 21.5 13.8 30.3 In-center hemodialysis 77.5 64.1 74.8 55.6 73.4 50.5 Home hemodialysis 1.6 4.8 2.3 3.8 1.1 2.1 Peritoneal dialysis 1.2 2.2 5.4 8.9 6.2 9.6 Other dialysis 2.4 2.8 2.9 3.3 1.6 2.1 Unknown 10.5 12.4 4.4 6.7 3.6 5.0 NOTE: Percentages may not add to 100 because of rounding. SOURCE: USRDS, 1990. rates almost 5 times that of the general U.S. population (Indian Health Service, 1987). These extreme mortality rates seem to correlate best with the incidence of ESRD secondary to diabetes mellitus, recorded as high as 89 percent of incident cases in the Aberdeen area and 95 percent in the Pima tribe (Nelson et al., 1988). The differences in survival between the races are related to the mode of TABLE 5-9 Survival of Black Versus Other Dialysis Patients by Year of Incidence   Survival (%)   Black Othera 1-Year Survival     1978 79.9 74.0 1983 79.9 73.7 1988 82.4 77.1 2-Year Survival     1978 64.4 57.4 1983 65.0 57.0 1987 66.7 59.8 5-Year Survival     1978 36.0 36.5 1984 31.5 30.5 NOTES: Adjusted for age, gender, and renal diagnosis. All survival rates include only patients who survived the first 90 days. a P = .0001. SOURCE: USRDS, 1990.

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Kidney Failure and the Federal Government treatment. Overall, blacks have higher average survival than whites on dialysis and similar survival following transplantation (USRDS, 1990). However, the average survival of the transplanted kidney is poorer for blacks. Although there has been substantial improvement overall in the survival of the grafts, blacks have always lagged behind whites. This is shown in Figure 5-5 for cadaveric grafts surviving 2 years after transplantation. The result is similar for living related donor grafts for the same and longer time periods. Although these data do not control for possible influences on allograft survival, such as HLA matching and age, gender, and race of organ donor, studies that control for these potentially confounding factors have, for the most part, shown similar shortened allograft survival in black recipients (Orial et al., 1982; Krakauer et al., 1983; USRDS, 1990). There are exceptions, including Michigan (Weller et al., 1985) and Ohio State Medical Center (Sommer et al., 1989). Other investigators (Purdue and Terasaki, 1982; Mcdonald et al., 1984) also have reported that race was not an important predictor of survival. The disparities in these results may arise in part from variations in immunosuppressive regimes, patient comorbidity, and choice of cofactors to be included in the analysis. However, considerable evidence still remains, including national data from HCFA and the USRDS, indicating that blacks reject their grafts more frequently than do whites. FIGURE 5-5 Two-Year Survival of Transplanted Cadaver Kidneys, by Race, 1978–88 SOURCE: USRDS, 1990

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Kidney Failure and the Federal Government The above data describe considerable racial and ethnic variation in incidence, treatment, and outcomes of end-stage renal failure. Although data suggest a physiologic contribution to the discrepancies in the development of ESRD among races, racial and ethnic variations in access to and utilization of preventive health care and in the implementation of renal replacement therapy are likely important contributors to these patterns. It is important that future research and policy decisions address the sociologic and economic differences in access to health care relative to outcomes in these populations. CONCLUSION The epidemiology of ESRD is in its early stages of development. This chapter makes clear, however, that the ESRD population is highly diverse and that its composition has changed over time. Children with ESRD have special problems that deserve explicit attention. Elderly ESRD patients are growing as a percentage of the patient population and confront providers and policy makers with an array of new challenges. The prominence of diabetes and hypertension as causes of renal failure highlights the importance of finding ways to control and prevent these diseases and thus prevent the progression to renal failure of individuals with these diagnoses. Finally, the striking disparities between the rates of kidney failure among minority populations and the white population underscore the need to understand the causal factors and the effective preventive interventions for individuals in these groups long before they arrive at the stage of permanent kidney failure. The material in this and the previous chapter suggests that permanent kidney failure correlates with lower socioeconomic status (SES). However, the ESRD patient population has not been systematically studied in SES terms and existing data do not permit a direct examination of relation of SES to renal failure. Such an examination is clearly called for. The nation may pay a high price through the ESRD program for inadequate health care and the lower health status of lower socioeconomic groups. NOTES 1.   New elderly ESRD patients without a specified diagnosis were excluded from these calculations. These patients amounted to 58.5 percent of the total in 1978 but only 7.7 percent in 1988. 2.   Nearly 50 percent of patient records lack primary diagnosis information through 1980. 3.   Beginning in 1981, HCFA achieved relatively complete data tracking of Native Americans and Asians/Pacific Islanders treated for ESRD.

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