CPAP may prevent renal tubular damage in patients with obstructive sleep apnea

Obstructive sleep apnea (OSA) Individuals with severe chronic intermittent hypoxia (IH) and significant comorbidities are more prone to renal tubular damage when they are younger.

Researchers have reported in a study published in  Sleep Medicine that use of CPAP reduces renal damage in such patients with obstructive sleep apnea

Obstructive sleep apnea comorbidities have a substantial impact on the etiology of chronic intermittent hypoxia. Patients with OSA have a greater frequency of chronic kidney disease than the general population, and renal function loss is closely associated with renal tubular damage.

However, nothing is known about how persistent IH brought on by OSA affects the renal tubules. In order to explore renal tubular injury in terms of chronic IH and assess the effects of continuous positive airway pressure (CPAP) on renal tubular injury, Rika Moriya and colleagues performed a retrospective clinical record survey.

For this study, multiple regression analysis and cluster analysis were used to do a retrospective review of clinical data, paying close attention to the urine N-acetyl-d-glucosaminidase (NAG) level and the 3% oxygen desaturation index (ODI).

The key findings of this study were:

1. Urinary NAG creatinine ratio (UNCR) was raised in patients with suspected OSA as their

3% ODI rose (n = 197, p 0.001), and the elevated UNCR reduced in patients with OSA after receiving CPAP therapy (n = 46, p = 0.014).

2. A multiple regression study revealed a correlation between UNCR and 3% ODI.

3. Three groups of patients with OSA were discovered by cluster analysis, including two younger age clusters, one of which had a high BMI, high 3% ODI, and a high incidence of severe comorbidities.

4. In a comparison examination of cases with younger ages (age 55, n = 82), patients with severe 3% ODI (3% ODI >40 events/h, n = 24) had higher UNCR levels (p = 0.014).

According to the data, OSA-induced chronic IH may have serious negative consequences on the renal tubules. Early diagnosis and CPAP therapy for OSA may slow the course of ESRD and renal tubular and tubulointerstitial damage. For both clinicians and health policy makers, it may be crucial to have a better understanding of the potential contribution of OSA-induced chronic IH to renal tubular and tubulointerstitial injury, given the significant financial burden and daily life restrictions associated with the start of renal replacement therapy.

Clarifying these links and determining if particular therapies outside of CPAP therapy have an effect on long-term clinical outcomes, such as lowering the incidence of CKD and delaying its development to ESRD, would require more investigation.

Reference: 

Moriya, R., Hokari, S., Ohshima, Y., Suzuki, R., Nagai, A., Fujito, N., Takahashi, A., Aoki, N., Watanabe, S., Koya, T., Nakayama, H., Izumizaki, M., & Kikuchi, T. (2023). Continuous positive airway pressure treatment reduces renal tubular damage in patients with obstructive sleep apnea: A retrospective single-center cohort study. In Sleep Medicine. Elsevier BV. https://doi.org/10.1016/j.sleep.2023.03.028