Night blood pressure responses to atenolol and hydrochlorothiazide in black and white patients with essential hypertension

Abstract

Background: Night blood pressure (BP) predicts patient outcomes. Variables associated with night BP response to antihypertensive agents have not been fully evaluated in essential hypertension.

Methods: We sought to measure night BP responses to hydrochlorothiazide (HCTZ), atenolol (ATEN), and combined therapy using ambulatory blood pressure (ABP) monitoring in 204 black and 281 white essential hypertensive patients. Initial therapy was randomized; HCTZ and ATEN once daily doses were doubled after 3 weeks and continued for 6 more weeks with the alternate medication added for combined therapy arms. ABP was measured at baseline and after completion of each drug. Night, day, and night/day BP ratio responses (treatment - baseline) were compared in race/sex subgroups.

Results: Baseline night systolic BP and diastolic BP, and night/day ratios were greater in blacks than whites (P < 0.01, all comparisons). Night BP responses to ATEN were absent and night/day ratios increased significantly in blacks (P < 0.05). At the end of combined therapy, women, blacks, and those starting with HCTZ as opposed to ATEN had significantly greater night BP responses (P < 0.01). Variables that significantly associated with ATEN response differed from those that associated with HCTZ response and those that associated with night BP response differed from those that associated with day BP response.

Conclusions: In summary, after completion of HCTZ and ATEN therapy, women, blacks, and those who started with HCTZ had greater night BP responses. Reduced night BP response and increased night/day BP ratios occured with ATEN in blacks. Given the prognostic significance of night BP, strategies for optimizing night BP antihypertensive therapy should be considered.

Clinical trial registration: Clinicaltrials.gov identifier NCT00246519.

Keywords: ambulatory blood pressure; atenolol; blood pressure; hydrochlorothiazide; hypertension; night/day ratio..

Figures

Figure 1.

Hourly mean systolic and diastolic baseline blood pressures in 281 white and 204 black Pharmacogenomic Evaluation of Antihypertensive Responses study participants. Hourly mean values that are significantly different across race are shown with an asterisk (P < 0.05).

Figure 2.

Systolic and diastolic blood pressure response to atenolol (ATEN) and hydrochlorothiazide (HCTZ) monotherapy and combined therapy in white (W) and black (B) male (M) and female (F) Pharmacogenomic Evaluation of Antihypertensive Responses study participants. (a) Nighttime monotherapy. (b) Nighttime combined therapy. (c) Daytime monotheraphy. (d) Daytime combined therapy. *P <0.05 between whites and blacks. **P < 0.05 between ATEN and HCTZ treatment within a race/sex subgroup. Abbreviation: NS, not significant.

Figure 3.

Change in night/day systolic blood pressure (SBP) and diastolic blood pressure (DBP) ratios after each step of drug therapy in white (W) and black (B) Pharmacogenomic Evaluation of Antihypertensive Responses study participants. Night/day SBP and DBP ratios were determined using mean night BP values divided by mean day BP values. *P < 0.05 for add-on theraphy vs. end of monotherapy. **P < 0.05 for atenolol monotherapy vs. baseline. Abbreviations: ATEN, atenolol; HCTZ, hydrochlorothiazide.