**4. Changes in sleep architecture**

386 Chronic Kidney Disease

male patients are more likely to have sleep complaints than women (10). Caucasian patients have a higher prevalence of restless legs syndrome than African American (1, 10). Subjective complaints are also high in patients with increased caffeine intake, pruritis, bone pain, cigarette use, and premature discontinuation of dialysis (1). As in general population, increased stress, anxiety, depression, and worry are also associated with poor subjective

No consistent relationship has been detected between subjective sleep complaints of poor sleep and Blood Urea Nitrogen (BUN), Creatinine, or Kt/V (see glossary) (1, 11, & 13). Anemia has been associated with complaints of poor sleep with improvement after treatment with recombinant erythropoietin (14). Mild hypercalecmia has also been associated with increased frequency of subjective insomnia (15). Frequent napping during day time dialysis may also be a factor which contributes to fragmented sleep at night.

Nocturia, one of the earliest symptoms of kidney disease may also lead to reduced sleep due to frequent awakening. Untreated sleep apnea has also been linked to nocturia. Most of the awakenings attributed to nocturia by patients are attributable to sleep disorders, particularly

sleep quality in dialysis patients (10-12).

Fig. 1. Factors associated with sleep disturbances.

sleep apnea (63).

**3. Factors contributing to sleep disturbances (Figure 1)** 

Nocturnal sleep of patients on dialysis is short and fragmented with total sleep time ranging between 260 and 360 minutes. Sleep efficiency is between 66% and 85% with a large amount of wakeful time (77-135 min), and numerous arousals (25-30/h of sleep) (16-18). Patients have increased patterns of Stage I and Stage II sleep, decreased slow wave (deep sleep), and REM sleep (17, 18). Thus dialysis patients have both reduced quantity and quality of sleep. Changes in sleep patterns in advanced CKD patients who are not on dialysis are similar to patients on dialysis (21)
