Winkelman JW, Chertow GM, Lazarus JM
Restless leg syndrome in end-stage renal disease
Am J Kidney Dis
(Sep) 28:372-378 1996
These investigators administered a questionairre to 222 hemodialysis
patients in Boston, and compared their answers to those of 129 cardiology
outpatients without renal disease. Symptoms of restless legs syndrome (RLS)
and self-reporting of periodic leg movements to indicate periodic limb
movement disorder (PLMD) were recorded in the questionairre; lab data,
dialysis compliance and nerve conduction study (NCS) data (in 54% of
patients) were recorded.
A RLS symptom score of 3 - 11 was calculated.
ESRD patients reported delayed sleep onset (41.1 v. 23.4 mins), less total
sleep time (6.2 vs 6.7 hrs), and the perception of a moderate or severe
sleep problem (36% vs. 11%) statistically more often than cardiac patients.
The RLS symptom score was correlated with perceived sleep problems,
nocturnal awakening, sleep onset latency, less total sleep time and use of
sleeping medications; it was not correlated with age, years on dialysis,
URR, or abnormal NCS. Pruritus severity was not related to serum
phosphate, calcium, PTH or dialysis intensity. Self reported early
discontinuation of dialysis was correlated with RLS symptoms and with
perceived sleep problems, less total sleep time and with a lower
There was 2.5 yr follow-up on the patients; an RLS
symptom score of 7 or more was associated with a lower survival at 1 (0.82
vs. 0.91) and 2 years (0.62 vs 0.72) with P=0.06. The adjusted hazard
ratio associated with RLS was 1.85 (CI= 1.12 to 3.07; P<0.02). Diabetes
was not found to be a risk factor for mortality in this patient group.
Comment: This well studied group of patients adds to our understanding
RLS in dialysis patients. RLS in ESRD appears similar to the idiopathic
entity. Compared with sleep apnea, RLS seems to be of equal or increased
importance as a cause of sleep disturbance in dialysis patients.
Interestingly, neuropathy assessed by NCS was not associated with RLS, nor
was delivered URR. Low transferrin saturation was found to be associated
with RLS, as has been noted in idiopathic RLS, perhaps related to an effect
of iron on dopaminergic pathways in the CNS. A suggestive case was made
that RLS may be a major cause of patients signing off of dialysis early,
due to the inability to sit still, which contributes to an elevated
mortality rate from underdialysis. This correlation of elevated mortality
risk with RLS is indeed worrisome, although this study could not completely
adjust for other potential comorbidities.
(Stephen Pastan, M.D., Emory Clinic)