High prevalence of patients with a high risk for obstructive sleep apnoea syndrome after kidney transplantation--association with declining renal function.

BACKGROUND: Obstructive sleep apnoea syndrome (OSAS) is much more prevalent in patients on dialysis than in the general population. Our aim was to assess for the first time the prevalence of patients with a high risk for OSAS and its clinical correlates in a large sample of kidney transplanted patients. We also wanted to compare the prevalence of the disorder between waitlisted dialysis patients (WL) and kidney transplanted patients (Tx).
METHODS: One thousand sixty-seven kidney transplanted patients were asked to participate in a cross-sectional survey ('TransQoL-HU Study'). Socio-demographic data, history of renal disease, medication, comorbidity and laboratory parameters were collected at enrolment. Patients completed a battery of self-administered questionnaires including the Berlin Sleep Apnoea Questionnaire to assess risk status of OSAS.
RESULTS: The final analyses included 841 Tx and 175 WL patients. The prevalence of high risk for OSAS was similar in the transplanted group vs WL patients (27% vs 33%). In multivariate logistic regression analysis male gender, older age, lower educational status, worse kidney function, use of hypnotic drugs and comorbidity were independent predictors for high risk of OSAS in kidney transplanted patients.
CONCLUSIONS: High risk for sleep apnoea is highly prevalent in the kidney transplanted population. In addition to the well-known risk factors of OSAS (male gender, obesity, use of hypnotic drugs, comorbidity), impaired kidney function was also independently associated with high risk for OSAS.