Background: Sleep apnoea is common in patients with end-stage renal disease. Although individual case reports have described an improvement in sleep apnoea following kidney transplantation, there have been no longitudinal studies of a case series to determine what proportion of patients with sleep apnoea improve.
Methods: Dialysis-dependent patients awaiting kidney transplantation and pre-dialysis patients with an identified living donor kidney had overnight polysomnography, which was repeated several months after successful kidney transplantation. Patients were divided into apnoeic and non-apnoeic groups based on an apneoa-hypopnoea index (AHI) > 10/h during pre-transplant polysomnography and, following transplantation, apnoeic patients were further divided into responders and non-responders based on >50% reduction in AHI and/or AHI < 10/h.
Results: Eighteen patients (11 men, 7 women), aged 27-65, were studied. Pre-transplant sleep apnoea was present in 11 of 18 (61%) patients. Although transplantation was associated with a significant reduction in blood urea nitrogen and serum creatinine, there were no significant changes in AHI (pre vs post: 20.2 +/- 15.1 vs 23.5 +/- 21.3). Among the 11 apnoeic patients, only three met the criteria for a significant improvement ('responder'). There were no patient characteristics, sleep apnoea indices or renal function changes that distinguished responders from non-responders.
Conclusions: Sleep apnoea improves in a minority of patients with end-stage renal disease following successful kidney transplantation. Specific determinants of improvement were not identified.