Rapid decreases in blood pressure from antihypertensive treatment were associated with increased cancer mortality in the systolic hypertension in the elderly program

Background: Research on the association between antihypertensive drug treatment (HTDT) and cancer is equivocal. We tested the hypothesis that large, rapid decreases in blood pressure following HTDT are associated with higher cancer mortality. Methods: Data from the Systolic Hypertension in the Elderly Program (SHEP) with 15-year cause-specific follow-up for mortality were used. We used changes from baseline in seated and standing systolic blood pressure (SBP) measurements at 3,6,9, and 12 months after the initiation of HTDT. Hazard ratios adjusted for demographics, comorbidities, and competing risk of non-cancer-related deaths were estimated to determine the association between SBP change, as a continuous or time-dependent measure, and cancer-related death. Results: SHEP participants taking antihypertensive medication who exhibited a decrease in seated SBP of 29 mm Hg or more (50th percentile and above) at 3 months were at a 58% greater risk of cancer-related death during a 15-year follow-up compared with those with no decrease in SBP (P = 0.007,42% increased risk P = 0.02 for standing SBP). Those participants whose maximal seated SBP change occurred in the first 3 months of treatment had 2.6-times greater risk of cancer mortality compared with those whose maximal seated SBP change occurred at 12 months (P = 0.004). Conclusions: Large SBP decreases early in HTDT were associated with an increased risk of cancer-related death during a 15-year follow-up. Further studies are needed to confirm and explore the potential mechanisms for this association. Impact: Rapid decreases in blood pressure following HTDT may be a risk factor for cancer.