Periodic limb movements in sleep revealed by treatment of sleep apnea with continuous positive airway pressure in the advanced chronic kidney disease population

Abstract

The chronic kidney disease (CKD) population has a high incidence of sleep disorders, including sleep apnea (SA) and periodic limb movements in sleep (PLMS). SA and PLMS often occur concurrently and may predict mortality in the end stage renal disease (ESRD) population. In this study, we investigated whether sleep fragmentation secondary to SA masks the underlying frequency or severity of PLMS in 16 patients with CKD, dialysis and not-on-dialysis patients (CKD-ND), and if successful treatment of SA with continuous positive airway pressure (CPAP) results in the increased appearance of PLMS. All subjects had polysomnography (PSG) diagnosed SA. The mean apnea-hypopnea index (AHI) at baseline and with CPAP treatment was 49.8 ± 25.6/h and 5.2 ± 9.1/h, respectively. With successful treatment of SA with CPAP, PLMS index (PLMSI) increased 237.7% from baseline of 13.8 ± 23.8/h to 32.8 ± 33.7/h with CPAP treatment (p = 0.019). Arousing PLMS index (APLMSI) also increased 191.5% from mean baseline of 8.2 ± 18.2/h to 15.7 ± 18.5/h with CPAP treatment (p = 0.026). PLMS occur during uninterrupted NREM sleep. SA may mask the underlying incidence and severity of PLMS in CKD patients by disrupting NREM sleep. PLMS more than doubled during successful treatment of SA. Therefore, despite successful treatment of SA with CPAP, sleep deprivation may persist due to clinical manifestation of underlying PLMS in patients with CKD. The actual underlying prevalence and severity of CKD-associated PLMS are likely higher than appreciated and are suppressed by SA in the CKD population.