When CPAP Fails to lower blood pressure in OSA patients: a sub-analysis of the HIPARCO trial

Not all patients with resistant hypertension (RH) and obstructive sleep apnea (OSA) experience blood pressure (BP) reduction. Our objective was to investigate the characteristics of patients whose BP increases despite treatment with continuous positive airway pressure (CPAP).

We identified and characterized those patients from the randomized clinical trial HIPARCO experiencing increased BP despite treatment with CPAP, well-tolerated or otherwise. Multivariate logistic regression was used to determine the factors independently associated with increasing BP in these patients.

Of the 98 patients treated with CPAP, 79 showed good tolerance and 38 patients had an increase in 24 h-SBP or DBD, despite the CPAP treatment. In these patients, age, the value of baseline 24 h-SBP, history of ischemic heart disease, time from the diagnosis of RH, and the average hours of CPAP use were independently associated with an increase in BP levels, despite CPAP. The same variables were associated with an increase in BP in the sub-analyses of patients with good tolerance to CPAP (n = 71). Finally, there was a significant correlation between the number of hours of CPAP use and a drop in the increase in BP levels (r = 0.55; p = 0.001).

In older patients with greater initial uncontrolled systolic BP, previous history of ischemic heart disease and a longer course of RH, CPAP treatment (even when good adherence is observed) is associated with an increase in clinically significant BP levels. However, an increase in the number of hours of CPAP use was correlated with a progressive decline in the observed increase in BP.