Future Directions for Improving the Listings
In the course of its work, the committee encountered a number of knowledge gaps in evaluating the effectiveness of the cardiovascular listings. The gaps would be reduced, and the listings improved, by research in four areas, discussed in the following sections.
If health insurance reform increases access to health services, and if increased access helps ensure that tests and other procedures Social Security cannot provide because of high cost or risk, such as catheterization, are regularly performed, the cardiovascular listings could be revised to require such tests and other procedures to meet the Listings. Also, increased access may reduce the rate of decline in an individual’s health and the resultant inability to work caused by some impairments to the point that a listing is no longer needed. The Social Security Administration (SSA) should support research on the disability-related effects of health insurance reform, which are currently uncertain, to improve program planning and future updates of the Listings—not just the cardiovascular listings.
In evaluating the impact of the current Listings and alternatives for revising them, the committee had many questions that will be brought up the next time they are revised. Many of these questions could be addressed
with data that SSA already produces routinely or could obtain from a sample of case files.
One important lack of information the committee faced consistently was the dearth of data on the relationship between severity of anatomical impairment or other markers in the medical record with the likelihood that a claimant with those characteristics are allowed, first at Step 3, then at Step 5. SSA itself has programmatic data that could be used to address this question. For example, a sample of Step 5 allowances for a specific impairment could be analyzed retrospectively to see if there is a common feature in the medical record. If so, that feature could be made a listing-level criterion and thus allow these claimants more quickly. Currently, for example, an ejection fraction of 30 percent or less with certain symptoms or signs or very serious limitations on activities of daily living meets the heart failure listing, and an ankle-brachial index (ABI) less than 0.50 meets the peripheral artery disease (PAD) listing. An analysis of claims process data could find that functionally limited claimants with heart failure with an ejection fraction of 35 percent are nearly always allowed at Step 5, or that claimants with PAD with an ABI of 0.55 are invariably allowed at Step 5, and the listings could be revised accordingly. Similar analyses could be done of allowances that equal a listing; for example, if the rate of allowances equaling the listing for a particular impairment was increasing unexpectedly, the research might find that the medical community has adopted a new test to diagnose or determine the severity of the condition, and that test could be added to the listing so claimants could more easily and reliably be allowed at Step 3.
Another critical area where research is needed is on the effects of comorbidities that claimants with a cardiovascular impairment often have. Again, SSA has data that can be analyzed to illuminate the impact of these effects. A research project along these lines was suggested in the conclusion of Chapter 15. The project would track the percentage of claims of heart failure with a diagnosis of major depression and various ejection fraction cutoff points, for example, 35 and 40 percent, that are allowed at Step 5. If the rate is very high for any of these cutoff points, that is, 95 percent or higher, SSA could create a listing criterion for major depression in combination with that specific ejection fraction value.
SSA could also pretest the impact of a proposed change in a listing by prospectively comparing a sample of claims while going through the regular process. The committee was pleased to learn that since the release of the 2007 Institute of Medicine report on improving the Social Security disability decision process (IOM, 2007), SSA has engaged a National Institutes of Health group in conducting such analyses of disability program data. Analyses of the use of the Listings are being done within SSA’s Office of Disability Programs.
Another area of interest would be to study the degree of variability among examiners, or interrater reliability, in applying the Listings, which
would provide some insight into which listings need to be reconsidered and revised. For example, the same case or set of cases could be given to multiple adjudicators to review consistency in the decisions made.
CORRELATION OF IMPAIRMENTS AND FUNCTIONAL LIMITATIONS
SSA would benefit from research on the relationship among various degrees of anatomical impairment, which can be fairly objectively determined, and the functional limitations of individuals with those impairments. A body of research shows the average exercise limitations of individuals with a particular diagnosis, such as the limitations on the walking capacity of patients with PAD, defined as an ABI less than 0.90. However, little information is available on limitations by degree of severity, that is, an ABI less than 0.50 versus 0.40 versus 0.30, which would be more useful for validating and fine-tuning the criteria in the PAD listing.
In addition, little information is available on the relationship between functional assessment performed with a 10-minute treadmill or exercise bike test and the capacity to work an 8-hour workday. Well-validated and up-to-date information on the metabolic equivalents of task needed for various work-related activities is also needed. Current evidence is dated and limited to a small range of activities (Ainsworth et al., 2000).
TRUE PREVALENCE OF AND TRENDS IN IMPAIRMENTS THAT MEET THE SOCIAL SECURITY DEFINITION OF DISABILITY OR MEET THE LISTINGS
This information is needed for program planning and budget projections, but it would also be useful in validating the Listings. Currently, key information about the performance of the Listings is absent, such as sensitivity and specificity (or type 1 and type 2 errors), positive and negative predictive values, and overall accuracy, because the underlying rates of true disability are not known. SSA has begun and abandoned several efforts to determine the prevalence of disabilities that meet the statutory definition of disability and the validity of the Listings, probably because of the technical difficulties and cost. However, it seems that it ultimately would be cost effective to conduct this research, given the large dollar value of the benefits attached to disability determination decisions.
CONCLUSIONS AND RECOMMENDATION
SSA has a substantial in-house research program and supports some external research, but most of it is related to the Old Age and Survivors Insurance program and retirement behavior and trends rather than the Dis-
ability Insurance and Supplemental Security Income programs and disability prevalence and trends. Recently, the agency has expanded its research efforts related to the Listings. To better assist the next round of revisions of the cardiovascular and other listings, SSA should sponsor, both in house and externally, a full and balanced program of research in the four areas listed above.
RECOMMENDATION 16-1. SSA should plan and sponsor a balanced program of research to improve the reliability, validity, and utility of the Listings in four areas: policy implications, programmatic issues, correlation of impairments and impairment severity with functional limitations related to work capacity, and the underlying prevalence of and trends in impairments in the population. This program would also enable SSA to enhance the other steps of the disability determination process.
Ainsworth, B. E., W. L. Haskell, M. C. Whitt, M. L. Irwin, A. M. Swartz, S. J. Strath, W. L. O’Brien, D. R. Bassett Jr., K. H. Schmitz, P. O. Emplaincourt, D. R. Jacobs Jr., and A. S. Leon. 2000. Compendium of physical activities: An update of activity codes and MET intensities. Medicine and Science in Sports and Exercise 32(Suppl):S498–S516.
IOM (Institute of Medicine). 2007. Improving the Social Security disability decision process, edited by J. D. Stobo, M. McGeary, and D. K. Barnes. Committee on Improving the Disability Decision Process: SSA’s Listing of Impairments and Agency Access to Medical Expertise. Washington, DC: The National Academies Press.