The need to treat mild hypertension. Misinterpretation of results from the Australian trial
J. D. Abernethy
Despite the clear-cut result of the Australian Therapeutic Trial in Mild
Hypertension, which demonstrated prospectively the benefit of treatment of
diastolic blood pressure in the range of 95 to 109 mm Hg, a retrospective
analysis that classified subjects by the average diastolic pressure level
attained during the trial purported to show an absence of treatment benefit
at lower average diastolic pressures and a negative treatment effect at
higher levels. However, the method of classification by average attained
diastolic pressure introduced substantial selection bias, invalidating the
retrospective analysis and rendering as spurious both the deleterious
treatment effect and its lack of efficacy at lower diastolic levels.