Clinic-based effectiveness studies of sleep disordered breathing (SDB) treatment in reducing blood pressure (BP) in resistant hypertension (RHTN) versus non-RHTN are sparse. We hypothesize that continuous positive airway pressure (CPAP) use in SDB reduces BP significantly in RHTN and non-RHTN in a large clinic-based cohort.
Electronic medical records were reviewed in patients with SDB and comorbid RHTN and non-RHTN for CPAP therapy initiation (baseline) and subsequent visits. We estimated generalizable BP changes from multivariable mixed-effects linear models for systolic, diastolic, and mean arterial blood pressures (SBP, DBP, MAP), adjusting for RHTN status, age, sex, race, body mass index (BMI), cardiac history, and diabetes, and repeated measure correlation.
Of 894 patients, 130 (15%) had RHTN at baseline (age: 58 ±12 years, 52 % male, BMI: 36 ± 9 kg/m2). RHTN patients had significantly higher BP overall (p<0.001), most notably for systolic BP (6.9 mmHg, 95%CI: 3.84, 9.94). In the year following CPAP initiation, improvements in BP indices did not generally differ based on RHTN status in which RHTN status was a fixed effect. However, there was a significant decrease in SBP (3.08 mmHg, 95% CI: 1.79, 4.37), DBP (2.28, 95%CI: 1.56, 3.00), and MAP (2.54 mmHg, 95% CI: 1.73, 3.36) in both groups.
In this clinic-based effectiveness study involving patients closely followed for BP control, a significant reduction of BP measures (strongest for SBP) was observed in response to CPAP which was similar in RHTN and non-RHTN groups thus informing expected clinical CPAP treatment response.