Prevalence of chronic kidney disease in obesity hypoventilation syndrome and obstructive sleep apnoea with severe obesity

Abstract

PurposeChronic kidney disease (CKD) is common in severe obstructive sleep apnoea (OSA), however prevalence in obesity hypoventilation syndrome (OHS) is not known. This study sought to compare prevalence of CKD in OHS and equally obese OSA patients with comparable apnoea hypopnoea indexes (AHI), and secondarily examine the impact of positive airway pressure (PAP) therapy on CKD parameters. MethodsEstimated Glomerular Filtration Rate (eGFR) and spot urine protein creatinine ratio (PCR) were obtained in patients with OHS (Partial pressure of carbon dioxide, PaCO2 > 45 mmHg) and OSA (AHI > 20 events per hour, PaCO2 < 45 mmHg) with a body mass index (BMI) > 40 kg/m2. Samples were obtained at baseline and after three months of PAP in both groups. ResultsPatients with OHS (n = 15, PaCO2 49 mmHg; daytime oxygen saturation, SpO2 94%; total sleep time with SpO2<90%, T90 308min) and OSA (n = 36, PaCO2 40 mmHg, SpO2 96%, T90 140min) were recruited. Stage 1–3 kidney function was present in 7 (46%) and 8 (22%) patients with OHS and OSA respectively (p = 0.08). Mean PCR was higher in OHS than OSA (23 ± 29 v 10 ± 6 mg/mmol; p = 0.03), while the prevalence of proteinuria was not different (40% v 19%, p = 0.19). Proteinuria was not significantly altered by three months of PAP. Moderate associations were demonstrated between eGFR, PaCO2, awake SpO2 and/or HbA1c (r > 0.5, p < 0.05) in OHS. ConclusionThe prevalence of CKD, primarily early-stage with proteinuria, is at least as frequent in OHS as it is in OSA, if not worse. Markers of CKD were not significantly impacted by PAP therapy.