Restless legs syndrome in maintenance haemodialysis patients

Sir, In the May issue of Nephrology Dialysis Transplantation, Sabbatini et al. [1] discussed insomnia in maintenance haemodialysis patients. They found that the prevalence of restless legs syndrome (RLS) in their patients was 46%. Their methodology for diagnosis of RLS was using a questionnaire devised by Holley et al. in 1992 [2]. As several conditions including cramps, neuropathy and akathisia may mimic RLS, the International RLS Study Group (IRLSSG) has formulated a well-designed questionnaire for accurate diagnosis of the condition [3]. These include: (i) a sensation of an urge to move the limbs (usually legs); (ii) motor restlessness to reduce sensations; (iii) quescegenic: onset or worsening of symptoms when at rest; and (iv) marked circadian variation in occurrence or severity of symptoms. RLS is diagnosed only if the responses to all the four questions are affirmative. The questionnaire used by the authors does not include all the IRLSSG questions relevant to the diagnosis of RLS. Hence, we feel that the figure quoted by them may not reflect a true picture of the prevalence of RLS in their patients.