A case‐control study on restless legs syndrome in nondialyzed patients with chronic renal failure

Abstract

Restless legs syndrome (RLS) is a possible consequence of end-stage renal disease. However, conclusive data on the association between RLS and chronic renal failure (CRF) in nondialyzed patients are still lacking. The aims of this study were: (1) to look for an association between RLS and CRF in nondialyzed patients; (2) to analyze the characteristics of RLS and its consequences on nocturnal rest in nondialyzed patients with CRF; (3) to identify possible predictors of RLS occurrence in nondialyzed patients with CRF. We recruited 138 nondialyzed patients with CRF (mean age: 69.8 +/- 11.7 years; male: 61.6%) and 151 controls (mean age: 60.2 +/- 18.6 years; male: 42.4%). An expert in sleep medicine investigated the presence of RLS by means of a face-to-face interview. Fifteen nondialyzed CRF patients and five controls were diagnosed as RLS affected. A multivariate analysis confirmed that RLS was independently associated with CRF in nondialyzed patients (P = 0.004). CRF patients RLS(+) were more commonly women and showed the presence of an iron deficiency compared with the RLS(-) ones. Independent predictors of RLS in nondialyzed CRF patients were: female sex (OR: 10.7, 95% CI: 2.2-31.3; P = 0.004) and percentage of transferrin saturation (OR: 0.6, 95% CI: 0.4-0.9; P = 0.04). This is the first case-control study able to recognize an association between RLS and CRF in patients not yet on dialysis. Nephrologists should investigate and treat RLS in their nondialyzed patients with CRF. In particular, physicians should carefully investigate women and patients with iron deficiency in the presence of RLS symptoms.

Restless Legs Syndrome: An Unresolved Uremic Disorder after Renal Transplantation

“…Although this female to male ratio for RLS has been reported in CKD [12, 25], it had not been consistently reproduced in surveys of renal transplant patients [8-10]. Since renal disease is more prevalent in men, this disparity could be explained by the different characteristics of the population analyzed and the unreliability of questionnaire-based diagnosis [13, 26]. Interestingly, our results indicate a more accurate positive predictive value of the self-administered questionnaire for women (65%) than for men (33%), suggesting that the higher rate of RLS mimics among men might misleadingly lead to the apparent equal gender distribution found in previous studies [8-10].…”

“…Previous researchers have already noted a declining rate of RLS after transplantation, suggesting a benefit from the removal of “uremic influences” by the functional graft [8, 9, 11]. However, whether the frequency of RLS in renal transplant is above average and whether RLS contributes to the cardiovascular disease burden associated with renal disease are still controversial [5, 8, 9, 13, 23]. …”

“…The reported prevalence of RLS among ESRD is as high as 30–50%; however, most surveys are based on self-administered questionnaires, without objective measures like polysomnography or even expert examination [8-12]. While Merlino et al [13] reported a 10.9% prevalence of RLS in non-dialysis chronic kidney disease (CKD) after expert investigation, we documented a 4.5% prevalence of RLS in this group of patients, similar to the frequency reported for the general population [13, 14]. In agreement with other researchers, we found that questionnaire-based RLS diagnosis in non-dialysis CKD dramatically falls after expert examination.…”

Cardiovascular comorbidity in patients with restless legs syndrome: current perspectives

“…For example, some studies report a prevalence of 12%-25%. [101][102][103] Other studies in CKD patients (but not on dialysis) report a similar prevalence of 10%-30% regardless of CKD stage, [104][105][106][107] whereas in renal failure clinics in USA and Europe, it fluctuates from 11% to 58%. 9 In addition, PLMS may affect ~50%-70% of patients with ESRD.…”

The use of rotigotine in the treatment of restless legs syndrome

“…RLS can occur secondary to a number of disorders including end-stage renal disease [Gigli et al 2004;Walker et al 1995], nondialysed patients with chronic renal failure [Merlino et al 2010], pregnancy [Manconi et al 2004], hyposideremia [O'Keeffe et al 1994], diabetes [Merlino et al 2007], polyneuropathy [Rutkove et al 1996] and several neurological disorders (such as multiple sclerosis [Manconi et al 2008]) and has iatrogenic forms. Secondary forms of RLS are characterized by a low frequency of positive family history, a late age at onset of symptoms, the antecedence of onset of the main clinical condition to RLS onset, and, most importantly, the amelioration/disappearance of RLS symptoms following remission of the main clinical condition.…”