“Normal” blood pressure predicts higher mortality in frail older adults with cardiovascular diseases: data from the SARCOS study

Background Controlling blood pressure in very elderly and frail patients has been a challenge in clinical practice. Epidemiological studies have shown that BP>130x80 mmHg reduces mortality, while clinical trials have shown that BP ≤130x80 mmHg reduces mortality. The ideal BP in this population remains undetermined. Aim To estimate observational association between baseline blood pressure ≤130 x 80 mmHg and mortality in frail older adults with CVD. Patients and methods Longitudinal analyses of 18 months with 434 individuals aged ≥ 60 years from a community geriatric cardiology clinic. CVD, other chronic diseases, frailty status, heart rate, and blood pressure were assessed at the beginning of the study. Frailty was diagnosed according to Fried's criteria, and blood pressure (BP) was measured using an air sphygmomanometer, as recommended by the 2020 American Heart Association. Mortality was assessed through telephone calls. The variable of the association between frailty and SBP 130 mmHg was created with four categories: Frailty with SBP≤130 mmHg (FR-SBP≤130 mmHg, n= 98, 22.6%); Frailty with SBP>130 mmHg (FR-SBP>130 mmHg, n= 51, 11.8%); No frailty with SBP ≤130 mmHg (NoFR-SBP≤ 130mmHg, n=159, 36.6%); No frailty with BP >130 mmHg (NoFR-SBP>130mmHg, n=126, 29%). Cox regression and Kaplan-Meier analysis models were used. Mortality variables with 15% significance in univariate Cox models and p = 5% for all statistical tests were used. Results The mean age was 77.6 years (±7.24), with a prevalence of women. Frailty occurred in 149 (34.4%). During follow-up, 37 (8.52%) individuals died, among them, there was a high prevalence of frailty (n = 24; 64.9%; p < 0.001) and SBP ≤ 130 mmHg (n = 31; 83.8%; p = .003), but not with DBP ≤ 80mmHg (p=.158). In regard of the phenotypes, 56 (56.8%) subjects who died had FR-SBP ≤ 130 mmHg, 10 (27%) No-FR-SBP ≤ 130 mmHg, 3 (8.1%) FR-BP>130 mmHg, and 3 (8.1%) NoFR-BP>130 mmHg. In the unadjusted analyses, frailty presented HR: 5.01 (1.18 – 21.22; p<0.001) and SBP ≤130 mmHg HR: 3.77 (1.57 – 9.03; p.003). In adjusted analyses with NoFr-PA>130mmH group as reference, the FR-SBP≤130mmHg HR: 6.42 (1.79-23.06; p=.004), FR-SBP>130mmHg HR: 2.80 (0.56-14.05; p=.208); NoFR-SBP ≤130mmHg: 2.49 (0.65-9.50; p=.180). Conclusion In frail older adults with CVD the systolic blood pressure ≤130 mmHg increases the mortality independently of the comorbidities. Diastolic blood pressure ≤80 mmHg, alone or in combination with SBP, did not modify the risk of mortality.