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The following is a summary of “Association between elevated cystatin C levels and obstructive sleep apnea hypopnea syndrome: a systematic review and updated meta-analysis,” published in the February 2025 issue of the BMC Pulmonary Medicine by Fu et al.

This study aims to investigate differences in cystatin C levels between patients with Obstructive Sleep Apnea Hypopnea Syndrome (OSAHS) and healthy controls, assess the role of cystatin C in the development of cardiovascular and cerebrovascular complications in patients with OSAHS, and evaluate the impact of surgical intervention or continuous positive airway pressure (CPAP) therapy on cystatin C levels. A comprehensive literature search was conducted across multiple medical databases, including PubMed, CNKI, EMBASE, Web of Science, and WanFang, up to October 1, 2024, to identify relevant studies. The analysis included a systematic review of cystatin C levels in patients with OSAHS versus controls, pre-and post-treatment variations following surgery or CPAP therapy, correlation coefficients between cystatin C levels and sleep monitoring indices, and the HR of cystatin C in predicting cardiovascular and cerebrovascular disease risk in patients with OSAHS. 

Meta-analyses utilized standardized mean difference (SMD) and correlation coefficients (COR) as effect variables, applying either a fixed-effect model (for low heterogeneity, I² < 50%) or a random-effect model (for significant heterogeneity). A total of 40 studies were included in the final analysis, revealing that serum/plasma cystatin C levels were significantly elevated in patients with OSAHS compared to controls (SMD = 0.65, 95% CI: 0.50–0.79, P < 0.001). Subgroup analyses stratified by mean body mass index (BMI), age, ethnicity, and study design confirmed consistently higher cystatin C levels in patients with OSAHS. Importantly, CPAP therapy significantly reduced serum/plasma cystatin C levels, suggesting a beneficial impact on systemic inflammation and renal function. Furthermore, increased cystatin C levels were identified as a potential risk factor for stroke and MACC in patients with OSAHS. 

Additionally, cystatin C levels exhibited a positive correlation with AHI scores and ODI, reinforcing their relevance in disease severity assessment. These findings underscore the clinical utility of cystatin C as a biomarker for evaluating OSAHS severity, predicting cardiovascular and cerebrovascular risks, and monitoring treatment efficacy. Future research should explore the mechanistic pathways linking cystatin C to OSAHS-related comorbidities and assess its potential as a therapeutic target in mitigating disease progression.

Source: bmcpulmmed.biomedcentral.com/articles/10.1186/s12890-025-03508-0