Obstructive sleep apnea (OSA) is highly prevalent in chronic kidney disease (CKD) patients and strongly linked to obesity, metabolic syndrome, and type 2 diabetes. Besides elevating cardiovascular disease risk, OSA may worsen renal function and diminish quality of life, making its understanding critical for CKD patient health.

This study will establish a large, long-term cohort of non-dialysis CKD patients to identify OSA risk factors, explore OSA's association with adverse renal outcomes, and determine OSA prevalence and epidemiological characteristics within the CKD population. The findings will provide a scientific foundation for early OSA identification, diagnosis, and intervention in CKD patients.

Inclusion Criteria:

• Voluntarily sign the informed consent form;

  • Aged ≥ 18 years and < 75 years;
  • Patients with CKD stages 3-4, with an eGFR of 15-60 ml/min/1.73m² calculated using the CKD-EPI formula for at least 3 months.

Exclusion Criteria:

• Patients receiving oxygen therapy or continuous positive airway pressure (CPAP) treatment;

  • Patients with other sleep disorders, including restless legs syndrome, periodic limb movement disorder, etc.;
  • Patients with other severe comorbidities: Severe heart failure (NYHA class III or IV); Myocardial infarction, unstable angina, or stroke within the past 3 months; Severe arrhythmias requiring medication or device therapy; Respiratory diseases, including COPD, asthma, thoracic deformities, etc.; Neurological disorders, including myasthenia gravis, Parkinson's disease, Alzheimer's disease, etc.; Active liver disease or severe hepatic insufficiency; Psychiatric conditions, including depression, anxiety disorders, etc.; History of malignancy within the past 5 years (except cured basal cell carcinoma); Uncontrolled hyperthyroidism;
  • Patients who underwent surgery or had acute infections within the past 3 months;
  • Current heavy alcohol consumption:Females: >3 drinks/day or >7 drinks/week; Males: >4 drinks/day or >14 drinks/week (1 standard drink = 14g of alcohol)
  • Current use of medications that may severely interfere with sleep, such as antipsychotics, antiepileptics, antiparkinsonian drugs, antidepressants, opioids, etc.;
  • Females who are pregnant or lactating at screening or baseline;
  • Inability to comply with the study due to: Low education level, language barriers, inability to tolerate or complete sleep monitoring, or other reasons preventing completion of study procedures (e.g., follow-up);
  • Deemed unsuitable for participation by the investigator's judgment.

The participants will be recruited from department of Nephrology, Nanfang Hospital