Reliability of a questionnaire screening restless legs syndrome in patients on chronic dialysis

The aim of this study is to evaluate the reliability of a self-administered questionnaire on leg discomfort and restlessness as a screening tool for restless legs syndrome (RLS) in a population of chronically dialyzed patients.

One hundred twenty-seven patients on chronic hemodialysis therapy filled in a self-administered questionnaire including 4 diagnostic questions for RLS and 12 subsequent questions on clinical characteristics of leg discomfort. Two neurologists trained in sleep medicine blinded to questionnaire answers evaluated all patients and diagnosed RLS according to criteria of the International Restless Legs Syndrome Study Group. We compared questionnaire results in terms of RLS diagnosis with direct patient evaluation performed by neurologists used as a gold standard.

The questionnaire showed a low sensitivity and specificity and did not prove reliable for screening for RLS in uremic patients. False-positive results seem to be caused by the presence of other leg symptoms and neurological objective signs suggesting peripheral neuropathy; false-negative results may be caused by the moderate severity of leg discomfort and its poor appraisal.

Our study suggests caution in evaluating results of questionnaires to screen for RLS in patients with chronic renal insufficiency on dialysis therapy.