Department of Nephrology University Frderico II Naples Italy Email: sabbatin{at}unina.it
Sir,
RLS is a well-defined clinical syndrome, characterized by the association of different symptoms, according to the criteria suggested by IRLSSG [1]. Nonetheless, in our recent study about sleep disturbances [2], we decided to define, as affected by RLS, all the patients answering positively to the last generic question of our questionnaire (Do you have restlesslegs with nocturnal waking and walking?), which was opportunely explained. It is obviously possible that patients with just one symptom of the syndrome have been considered affected by RLS, thus overestimating its true prevalence. On the other hand, our intention was to compare our data with those published previously in 1992 by Holley [3] and in 1995 by Walker [4] in which a similar definition of the syndrome was given and a significant correlation was detected between RLS and higher BUN levels, assumed as gross' markers of dialysis adequacy [4]. The use of the same definition allowed us to evaluate whether the better management of haemodialysis patients in the last 10 years (and the better adequacy of dialysis) had progressively reduced some symptoms of RLS linked to dialysis, like neuropathy, akathisia, cramps or had reduced those forms associated with iron and/or folate deficiency [5].
Interestingly, our study showed a clear trend toward a decreased prevalence of RLS symptoms from 81% [3] and 57% [4] up to our 45% [2], with the loss of any correlation between RLS and biochemical data of our patients on dialysis. This seems to confirm that, independently from the real incidence of idiopathic RLS, which remains particularly high in patients on dialysis compared with the general population [6], the progresses made in managing uraemic patients have a favourable impact on dialysis-related complications.
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