Worsening Kidney Function Is the Major Mechanism of Heart Failure in Hypertension: The ALLHAT Study.

OBJECTIVES: The authors aimed to quantify the extent to which the effect of antihypertensive drugs on incident heart failure (HF) is mediated by their effect on kidney function.
BACKGROUND: The authors hypothesized that the dynamic change in kidney function is the mechanism behind differences in the rate of incident HF in ALLHAT (Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial) participants randomized to lisinopril and chlorthalidone, in comparison with those randomized to amlodipine and doxazosin.
METHODS: Causal mediation analysis of ALLHAT data (1994 to 2002) included participants with available baseline and 24- to 48-month estimated glomerular filtration rate (eGFR) (N = 27,918; mean age 66 ± 7.4 years; 32.4% Black, 56.3% men). Change in eGFR was the mediator. Incident symptomatic HF was the primary outcome. Hospitalized/fatal HF was the secondary outcome. Linear regression (for mediator) and logistic regression (for outcome) analyses were adjusted for demographics, cardiovascular disease, and risk factors.
RESULTS: There were 1,769 incident HF events, including 1,359 hospitalized/fatal HF events. In fully adjusted causal mediation analysis, the relative change in eGFR mediated 18% of the effect of chlorthalidone, and 33% of lisinopril on incident symptomatic HF, and 25% of the effect of chlorthalidone, and 41% of lisinopril on hospitalized/fatal HF. In participants with diabetes, the relative change in eGFR mediated nearly 50% of the effect of lisinopril on incident symptomatic HF, whereas in diabetes-free participants, only 17%.
CONCLUSIONS: On the risk difference scale, change in eGFR accounts for up to 50% of the mechanism by which antihypertensive medications affect HF. (Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial [ALLHAT]; NCT00000542).