High risk of obstructive sleep apnea is a risk factor of death censored graft loss in kidney transplant recipients: an observational cohort study.

OBJECTIVES

Obstructive sleep apnea (OSA) is associated with increased risk of cardiovascular morbidity in the general population. The clinical significance of OSA among kidney transplant patients is unknown. Our aim was to investigate the association of "high risk of OSA" with death-censored graft loss and mortality in a large cohort of kidney transplant recipients.

PATIENTS AND METHODS

Using the Berlin questionnaire 1067 prevalent kidney transplant recipients were assessed for risk of OSA. Socio-demographic variables, laboratory parameters and data about graft loss and mortality were obtained from the medical records. Multivariable-adjusted associations of OSA risk with graft loss and with all-cause mortality was assessed in competing-risks regression models.

RESULTS

Of the 823 patients who completed the Berlin questionnaire 28% had high risk of OSA (HRO) at baseline. Patients with HRO were older (52±11 vs. 47±13years, p<0.001), had a higher prevalence of diabetes (22 vs. 15%, p=0.018), worse baseline kidney function (estimated glomerular filtration rate: 46±18 vs. 51±19ml/min/1.73m(2), p=0.001) and higher BMI (27±5 vs. 24±4kg/m(2), p<0.001). In multivariate models HRO was an independent predictor of graft loss among females after adjusting for age, comorbidity, hypertension, BMI, kidney function, duration of chronic kidney disease, other laboratory parameters and transplant-related data (HR=3.05; CI: 1.24-7.51; p=0.015), while HRO did not predict graft survival among males. HRO at baseline was not independently associated with all-cause mortality in the sample.

CONCLUSION

High risk of OSA is an independent predictor of graft loss among female kidney transplant patients.