NASAL CPAP AND WEIGHT-LOSS IN HYPERTENSIVE PATIENTS WITH OBSTRUCTIVE SLEEP-APNEA

Background-The high prevalence of obstructive sleep apnoea (OSA) in pa tients with systemic hypertension and of hypertension in patients with OSA suggests a causal link between the two disorders. This study was carried out to determine whether nasal continuous positive airway pres sure (CPAP) and weight loss affect daytime hypertension in OSA. Method s-Sixty hypertensive patients with OSA took part in the study; 33 acce pted nasal CPAP and used their machine for 5.7 (0.2) hours per night, and the remaining 27 patients refused nasal CPAP and upper airway surg ery so the only therapeutic intervention was a recommendation of weigh t loss. A significant change in hypertension during follow up was defi ned as either a change in mean blood pressure of at least 10 mm Hg (or more than 8%) without a change in drug treatment, or a reduction in d rug dosage with mean blood pressure within these limits. Weight loss w as defined as a body mass index of at least 5% below the baseline valu e. Results-After 512 (41) days, hypertension had become less severe in seven of 12 patients (58%) treated with weight loss only, in eight of 28 patients (29%) with nasal CPAP only, in two of five patients with nasal CPAP and weight loss, and in one of 15 patients without nasal CP AP or weight loss. Multivariate analysis of variance with the outcome of hypertension at follow up as the dependent variable revealed that o nly the percentage change in body mass index significantly contributed to the course of hypertension. Conclusion-The course of hypertension in OSA is more closely linked to weight loss than to elimination of sl eep apnoea by nasal CPAP.