The change and its clinical significance of serum cystatin C in elderly patients with obstructive sleep apnea hypopnea syndrome / 中华老年医学杂志

ABSTRACT

Objective To investigate the change of serum cystatin C (CC) level and its clinical significance in elderly patients with obstructive sleep apnea hypopnea syndrome (OSAHS),and to evaluate the diagnostic value of serum CC for renal impairment in elderly OSAHS patients.Methods Elderly snoring subjects (age ≥60 years) undergoing sleep apnea monitoring in our sleep laboratory were recruited.Patients were divided into simple snoring group,mild OSAHS group,moderate OSAHS group and severe OSAHS group according to the diagnostic criteria of American academy of sleep medicine.Anthropometric characteristics,lipid profiles,blood glucose,creatinine,estimated glomerular filtration rate (eGFR) and serum CC were compared between groups after age,gender and basic diseases were adjusted.The independent risk factors associated with serum CC were analyzed by Spearman's rank correlation and stepwise linear regression.Results Totally 89 elderly patients [70males and 29 females,aged (68.4±6.3) years in average] were collected.21 subjects were grouped as simple snoring,14 subjects as mild OSAHS,21 subjects as moderate OSAHS and 33 subjects as severe OSAHS.There were no differences in age,gender,basic diseases (hypertension and diabetes),lipid profiles,creatinine and eGFR among groups.The levels of body mass index,systolic blood pressure,diastolic blood pressure and serum CC were higher in severe OSAHS group than in simple snoring group [(28.3±3.9) vs.(24.6±5.9),(136.55±16.14) mm Hgvs.(122.43±16.64) mm Hg,(89.18±11.92) mm Hgvs.(78.10±9.55) mm Hg,(0.95±0.22) mg/L vs.(0.76±0.13)mg/L,respectively,all P＜0.05].Serum CC was significantly correlated with apnea hypopnea index (AHI),oxygen desaturation index,creatinine,eGFR,high sensitive C reactive protein (r=0.397,0.347,0.275,－0.354,0.254 respectively,all P％0.05).Regression analysis showed that AHI was an independent factor for serum CC (β=0.449,P＜ 0.001).Conclusions Serum CC level is increased in elderly patients with severe OSAHS.AHI is an independent factor for the increase of serum CC.Serum CC can be as an index for the early impairment of renal function in patients with OSAHS.