Does hormone analysis predict the antihypertensive response of basic medical treatment?

The antihypertensive effect of 200 mg metoprolol per day was compared to 25 mg hydrochlorothiazide over a period of four weeks. Metoprolol reduced mean arterial blood pressure from 120 +/- 13 mm Hg after placebo to 109 +/- 8 at the end of the study (n = 18; 38 +/- 12 years) (p less than 0.01). The corresponding values in the hydrochlorothiazide group were 119 +/- 13 mm Hg and 107 +/- 13 (n = 20; 33 +/- 12 years) (p less than 0.01). No significant difference between the groups was found for blood pressure at the end of the study. When blood pressure responders or non-responders of the metoprolol group were compared with the respective subgroup of the hydrochlorothiazide treated patients, no difference could be found for plasma renin activity as well as for aldosterone and PGE2- and PGF2a-excretion rates. However, when blood pressure responders were compared with non-responders within the same treatment group, plasma renin activity and PGE2-excretion rates were higher in the responder group corresponding with younger age in both treatments. Therefore high PGE2-excretion rate and high plasma renin activity might reflect a favorable vascular response to antihypertensive therapy. However, the hormonal analyses do not seem to help in the selection between a beta-blocker or a diuretic as a drug of first choice.