Systolic Blood Pressure and 8-Year Mortality in Community-Dwelling Older Adults. Does Frailty Modify This Effect?

Introduction: The current literature does not provide sufficient evidence to support different treatment targets for hypertension in older adults. Hypothesis: The effect of systolic blood pressure (SBP) on 8-years mortality may vary by frailty status in community-dwelling older adults. Methods: A frailty index (FI) was constructed according to the model of deficit accumulation with 38 items from the baseline exam at the Activity and Function in the Elderly Study. Each item had a score from 0 (no deficit) to 1 (deficit). FI represents the sum of all scores divided by 38. Cox-proportional hazards models adjusted for age, sex, education, smoking, diastolic blood pressure (DBP) and antihypertensive medications analyzed the association between SBP and 8-year mortality, evaluating the presence of effect modification by frailty. Results: A total of 940 participants were included in the analysis [median age 74, interquartile range (IQR 70.1, 81.0), 42.4% women]. The prevalence of hypertension was 54%, with median SBP 144.5 mmHg (IQR 135.0, 150.0), and median DBP 78.5 mmHg (IQR 71.0, 86.5). Median follow-up time was 8.1 years. A total of 201 deaths were observed. The median FI was 0.113 (IQR 0.069, 0.113), with 19.9% (n=187, 79 deaths) being identified as frail (FI 0.2). We detected effect modification by frailty (p-value interaction term <0.05). Table 1 summarizes the hazard ratios for the multivariable adjusted models stratified by frailty. Conclusions: Our results suggest the presence of effect modification by frailty with a possible protective effect of elevated SBP in frail subjects with respect to 8-year mortality even after adjustment for DBP and antihypertensive treatment.