Assessment of Diagnostic Technology in Health Care Rationale, Methods, Problems, and Directions (1989) / Chapter Skim
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7. Problems of Multi-Institutional Studies
7. Problems of Multi-Institutional Studies
Pages 129-142
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From page 129... ...
These include access to a larger patient population, which could reduce the time needed to obtain the required number of study subjects. Findings from the potentially more diverse population of a multicenter study might be more easily generalized to a wider patient population.
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From page 130... ...
Steering Committee The steering committee would be composed of principal investigators from Me major participating clinical centers and would be responsible for designing He protocol, approving protocol changes, and dealing wig operational problems. Approval of the protocol must involve aB investigators.
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From page 131... ...
The coordinating center would be able to detect major drops in the level of participation at any of the coccal units. The center should be in a separate location from the funding agency, which may have a stake in a particular outcome, and from any of the clinical centers, which may try to "dump" extra duties on a center conveniently located within their wads.
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From page 132... ...
higher than the blood glucose level used to define this disease. Thus, several centers enrolled fewer mild diabetics than did others.
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From page 133... ...
When the steering committee makes a decision about the study objective or the protocol, they must reach unanimity because, as the statistical coordinators of the UGDP study put it, "a majority decision cannot be a substitute where professional ethics and scientific conviction are concemed" (Klimt and Meinert 1966, p.
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From page 134... ...
For example, the dose of a hypoglycemic agent prescribed for a diabetic patient is usually flexible and is changed according to changes in the patient's status. The UGDP study protocol, however, specified "arbitrarily chosen fixed dosages that were maintained invar~andy throughout the project unless Be patient dropped out or developed major untoward events" (p.
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From page 135... ...
Because the study population of a multicenter trial is likely to be.more heterogeneous man the population from a single center, the sample variance within the intervention groups is likely to be greater. Thus, a larger number of patientsmay be ~quired.in a multicenter study to detect a specified difference between tests.
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From page 136... ...
Pooling the data and doing valid statistical analyses may be impossible. In the UGDP study, the widely disparate mortality results obtained win tolbutamide treatment at the different clinics clearly indicated that the tolbutamide treatment groups did not make up a homogeneous population.
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From page 137... ...
Even the most carefully designed study may fail to produce valuable information if the performance of individual centers is not adequately monitored to ensure correctness and thoroughness in the adm~n~stration of the protocol. Accurate and efficient data entry requires the individuals participating in data collection to cooperate win the staff of the coordinating center.
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From page 138... ...
win radionuclide (RN) studies in patients with intracranial disease, one institution used a mercury isotope and an unusual type of imaging instrument although me protocol had carefully specified sodium pertechnetate (McNeil 19791.
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From page 139... ...
More time win be needed to plan a multicenter trial because the investigators must agree on a focused study question and then approve a protocol designed to answer Cat question. Once a multi-institutional study is underway, the greatest challenge win be to obtain a uniform data set, that is, to remove sources of spurious variability between the centers.
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From page 140... ...
Practical aspects of decision making in clinical trials: The coronary drug project as a case study. Controlled Clinical Trials- I :363-376, 1981.
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From page 141... ...
Organization of multicenter clinical teals. Controlled Clinical Trials 1 :305-312, 1981.
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From page 142... ...
Quality of institutional participation in multicenter clinical teals. New England Joumal of Medicine 305:852-855, 1981.
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