POTENTIAL BIASES IN ASSESSING THE RISKS OF PHARMACOTHERAPY DUE TO MISMEASUREMENT OF DRUG EXPOSURE

We undertook this review to propose a minimum set of standards with wh ich any evaluation of pharmacotherapy should comply, to review the evi dence on which the relative risks of calcium channel blocker therapy f or hypertension are based, and to evaluate published studies against t hese proposed standards. We selected English-language primary study re ports published in peer-reviewed biomedical journals between 1995 and 1997. All the reviewed studies suffer from either possible misclassifi cation of antihypertensive drug therapy, mismeasurement of drug exposu re, or both. Given the inadequate documentation of subjects' drug ther apy, resulting relative risk estimates cannot be substantiated.