Chronic kidney disease (CKD) often accompanies obstructive sleep apnea (OSA). A causative connection of the two disease entities is uncertain. However, eliminating OSA improves the prognosis of CKD patients. In the present study we examined a possible relationship between OSA and CKD, and whether there would be a mutual enhancing interaction in the severity of the two diseases. The study was of a retrospective nature and encompassed 382 patients over the period of 1 January 2014-30 June 2015. The OSA diagnosis was supported by a polysomnographic examination in 363 (95.0%) patients. Blood samples were taken for the determination of kidney function indices. The influence on OSA and CKD of comorbidities also was examined. We found a high probability of a simultaneous occurrence of OSA and CKD; with the odds ratio of 3.94 (95% CI 1.5-10.3%; p = 0.005). The 363 patients with OSA were stratified into 73 (20.1%) mild, 98 (27.0%) moderate, and 192 (52.9%) severe OSA cases according to the apnea-hypopnea index. CKD was found in 43 (58.9%) patients with mild OSA, 73 (74.5%) with moderate OSA, and 137 (71.4%) with severe OSA. Most OSA patients also suffered from hypertension and obesity. For comparison, CKD was detected in 7 (36.8%) out of the 19 patients without OSA (p < 0.003). We conclude that CKD develops significantly more often in patients with OSA than in those without it, and CKD frequency increases with the severity of OSA.
Keywords: Apnea-hypopnea index; Chronic kidney insufficiency; Comorbidities; Obstructive sleep apnea; Renal function.