Effects of continuous positive airway pressure on renal function in adults with obstructive sleep apnea: a systematic review and meta-analysis

Purpose: Obstructive sleep apnea (OSA) is associated with increased risk of chronic kidney disease (CKD). OSA is highly prevalent among patients with CKD, suggesting a bidirectional link between the two conditions. Recent studies reported that continuous positive airway pressure (CPAP) may benefit renal function in OSA patients; however, uncertainties regarding their effects persist. Therefore, we examined the effects of CPAP treatment on renal function in adults with OSA. Methods: We systematically searched PubMed, EMBASE, Cochrane Library, Web of Science, and ClinicalTrials.gov for relevant studies from their inception until January 2024. Pooled estimates for all outcomes were calculated using a random-effects model. Primary outcome measures were the estimated glomerular filtration rate (eGFR) and urinary albumin-to-creatinine ratio (UACR). Results: Four randomized controlled trials (RCTs) and seven non-RCTs (NRCTs) (n = 2,660) were included. Compared with the control group, the CPAP group exhibited a significantly minimal alleviation in eGFR decline in NRCT (mean difference [MD] = 1.95, 95% confidence interval [CI] = 0.80 to 3.11, p < 0.001), but not in RCT (MD = 1.42, 95% CI = − 0.99 to 3.82, p = 0.25). No significant associations were found between CPAP therapy and UACR (MD = − 0.05, 95% CI = − 0.41 to 0.30, p = 0.77). Conclusion: Current research provides a low to moderate certainty of evidence, suggesting that CPAP therapy has little to no effect on alleviating the decline in renal function. However, further RCTs with larger sample sizes and extended follow-up periods are required.