Effectiveness of furosemide in uncontrolled hypertension in the elderly: role of renin profiling

BACKGROUND: Despite many advances in the treatment of hypertension, adequate blood pressure (BP) control in elderly patients continues to be a challenge. Optimal control of BP remains elusive because of issues relating to drug dosage and proper choice of therapeutic agents, including questions regarding the role of diuretics. METHODS: We examined the effect of diuretic treatment on BP in 12 elderly hypertensive patients whose hypertension was poorly controlled on previous drug regimens. We also evaluated the relationship of systolic, diastolic, and mean arterial BP (SBP, DBP, MAP, respectively) to changes in plasma renin activity (PRA), serum aldosterone (SA), atrial natriuretic peptide (ANP), and serum chemistries both before and after adding furosemide to the prior antihypertensive agents. RESULTS: At baseline, 83% of patients had low PRA (< 1 ng/mL/h). After furosemide, in 67% of patients, decreases in SBP (166 +/- 5 to 134 +/- 5 mm Hg; P <.001), DBP (82 +/- 4 to 71 +/- 4 mm Hg; P =.004), and MAP (111 +/- 3 to 92 +/- 3 mm Hg; P <.001), were associated with increases in PRA (2.1 +/- 1.2 to 5.1 +/- 1.8 ng/mL/h; P =.01) and SA (4.8 +/- 1.0 to 9.4 +/- 1.4 ng/dL; P =.01) and with decreases in ANP (101 +/- 28 to 58 +/- 11 pg/mL; P =.01) and body weight (77.5 +/- 3.6 to 76.4 +/- 3.3 kg; P =.02), findings consistent with volume mediated/salt sensitive hypertension. In the remaining 33% of patients, BP also decreased significantly, but there was no increase in PRA (0.15 +/- 0.05 to 0.10 +/- 0 ng/mL/h) or SA (9.2 +/- 2.2 to 7.0 +/- 0.8 ng/dL) and no decrease in ANP (66 +/- 5 to 75 +/- 18 pg/mL) (P = ns for all), suggesting alternate mechanisms for their responses. CONCLUSIONS: Many of the elderly hypertensive patients in our study had decreased PRA levels and showed significant reductions in BP after furosemide administration. Despite the associated increases in PRA and SA and decreases in ANP in 67% of patients, diuretic use remains important in the control of hypertension in this population.