Measures of clinical efficacy. The value of case finding in hypertensive renovascular disease.

An attempt was made to discover the difference in outcomes between treating all patients with essential and renovascular hypertension by drug therapy independent and ignorant of etiologic classification and identifying the patients with renovascular disease and operating on them. Outcomes were categorized as well without complications of hypertension, alive but suffering from a related morbid illness such as coronary or cerebral arterial disease, and dead from the complications of diagnosis, surgery or high blood pressure. The identification and surgical treatment of hypertensive renovascular disease resulted in an incremental benefit in morbidity over blind antihypertensive medical therapy only when the compliance with medical treatment was about 50 per cent or less (the rate suggested for most patient populations). The study underscores the extent to which the quantitative efficacy of diagnositc and therapeutic procedures depends not only on the inherent risks and benefits but also on related social and medical factors.