Retrospective analysis of antihypertensive drug therapy using various pharmacokinetic and pharmacodynamic methods

A retrospective analysis of blood pressure data from 42 published studies representing 23 different drug regimens and 971 patients was used to test various pharmacokinetic and pharmacodynamic methods for analyzing the effectiveness of antihypertensive drug therapy. The methods assume that a plot of the drug-induced decrement in diastolic pressure versus the pretreatment diastolic pressure yields an "ideal response line" that has a slope of 1.0 and an intercept on the pretreatment axis, representing the therapeutic endpoint of 90 mm Hg. The plot was used to test the congruence of each regimen with the "ideal" relationship, the percent of patient responses to each regimen that were successful in achieving the therapeutic endpoint, and the mean performance values for each regimen. The results obtained suggest that what is the ideal response in theory is not observed in practice. Six regimens showed no statistically significant difference between the calculated regression line and the ideal regression line. Seven regimens demonstrated overall success rates of 67% or greater in reducing pretreatment diastolic pressure to 90 mm Hg. Only one regimen--reserpine, hydralazine, plus hydrochlorothiazide--achieved combined performance factors of r2 greater than or equal to 0.67 and a success rate greater than or equal to 67%. Although interpatient variation in response is observed with all treatments studied, some regimens were markedly more effective and predictable than others in reducing diastolic pressure to the desired treatment endpoint.