Diederick E. Grobbee|Arno W. Hoes
Confounding and indication for treatment in evaluation of drug treatment for hypertension
Utrecht University|University Medical Center Utrecht|University Medical Center Utrecht|Utrecht University
nonrandomised comparisonsconfounding indication commonly creates unsurmountable problems nonrandomised research treatment effectsvalid inferences drawn rare circumstances groups patients indications different blood pressure lowered farthe debate continues marcus rose summary pointsconfounding indications treatment serious threat validity nonrandomised comparisons treatment effects conclusions efficacy treatment drawn comparisons treated untreated patients circumstances confounding indication nonrandomised study limited even removed design phase data analysis reported increased risks heart disease hypertensive patients low blood pressure treatment may attributable preexisting severe atherosclerosis rather overtreatmentunequivocal rejection nonrandomised studies assessing treatment effects unjustified