Obstructive sleep apnoea a stand alone risk factor for chronic kidney disease

İngilizce (OpenAlex)

Sir, We read the article by Chou et al. [ 1 ] with great interest. The authors aimed to determine whether patients with severe sleep apnoea ( n = 40) without meeting criteria for diabetes or hypertension could also be linked to chronic kidney disease. They showed that renal injury is present in nonhypertensive nondiabetic sleep apnoea patients, suggesting renal impairment as complication of severe sleep apnoea syndrome. In their study, renal impairment was measured as estimated glomerular filtration rate (eGFR) by using the Modification of Diet in Renal Disease (MDRD) formula. We would like to draw the attention to different currently available formulas for eGFR which may affect the conclusive results of studies and would also like to share data attained in our large sleep apnoea patient cohort (Uyar et al , unpublished data, n = 634) in relation with indexes of apnoea hypopnoea and GFR, the latter being estimated with four different methods ( Table 1 ). eGFRs with different four methods in patients with OSAS and control subjects a ABW, actual body weight; CKD-EPI, chronic kidney disease epidemiology collaboration; IBW, ideal body weight; OSAS, obstructive sleep apnoea syndrome. eGFRs with different four methods in patients with OSAS and control subjects a ABW, actual body weight; CKD-EPI, chronic kidney disease epidemiology collaboration; IBW, ideal body weight; OSAS, obstructive sleep apnoea syndrome. It is well known that the eGFR is limited because of remarkable variations with equations due to different ethnicity [ 5 ]. We evaluated data of patients who were diagnosed with obstructive sleep apnoea syndrome after referral to our sleep center at the Gaziantep University Medical Faculty between January 2005 and January 2010. Sleep studies were performed according to the guidelines of the American Academy of Sleep Medicine. The epworth sleepiness scale was used for evaluating daytime sleepiness. Obstructive sleep apnoea syndrome severity was defined as mild, moderate or severe when the apnoea hypopnoea index was 5–15, 15–30 and ≥30, respectively. As can be seen in Table 1 , there are important discrepancies between the four validated methods of eGFR. While the eGFR (actual body weight) and eGFR (ideal body weight) methods revealed significantly higher eGFR values, however, the MDRD and chronic kidney disease epidemiology collaboration methods revealed insignificant lower eGFR values. We definitely agree with the comment that race is a factor that can affect the measurement of glomerular filtration rate. We emphasized the importance of this possible major confounder factor, which should be kept in mind when interpreting the results. Conflict of interest statement. None to declare.