| dc.description.abstracteng | Sleep disturbances are a common problem
among patients with chronic renal insufficiency on hemodialysis and
often have multiple causes. One is the high prevalence of the
uremic form of restless legs syndrome (RLS). Associated symptoms,
such as uncomfortable sensations in the legs, an urge to move and
limb jerking, usually worsen in the evening, reducing the sleep
quality of affected individuals. The etiology of uremic RLS still
remains unclear; however, a neurotransmitter imbalance with a
predominance of excitatory effects due to metabolic changes seems
likely.Our research investigated whether an elevated plasma
concentration of the amino acid homocysteine is associated with RLS
occurrence in patients on hemodialysis. Total homocysteine plasma
concentration is known to be elevated in many patients on dialysis,
and the substance acts as an agonist at the N-Methyl-D-aspartic
acid (NMDA) receptor. Therefore, it has excitatory properties and
impairs the metabolism of dopamine, which is implicated in RLS. In
this study, we took blood samples from 52 renal-insufficient
patients on dialysis. Half of these patients suffered from uremic
RLS (RLSpos, n = 26) while the other half did not (RLSneg, n = 26).
Total plasma homocysteine concentrations (tHcy) were compared
between the two groups. Furthermore, we analysed several other
laboratory parameters which have previously been associated with
RLS in uremic as well as in non-uremic patients (creatinine, urea,
vitamin B12, folic acid, parathormone, hemoglobin, iron, ferritin,
phosphate, calcium, magnesium, and albumin). Additionally, we
compared subjective sleep quality between RLSpos and RLSneg
patients using the Pittsburgh-Sleep-Quality-Index-Questionnaire and
investigated a possible relationship between laboratory parameters
and sleep quality. Taking individual albumin concentrations into
account, a significant positive correlation between tHcy and RLS
occurrence was observed in our study (r= 0.246; p=0.045). All other
laboratory parameters did not differ significantly between the
RLSpos and RLSneg patients. Irrespective of group membership, bad
sleep quality was associated with higher concentrations of serum
parathormone (p=0.028). Sleep quality was significantly more
reduced in RLSpos compared to RLSneg patients (p=0.003). RLS
severity correlated with impaired sleep quality (r= 0.510;
p=0.004).Our results confirm that uremic RLS is a major cause of
sleep impairment among patients on hemodialysis. Subjective sleep
quality appears to deteriorate with increasing severity of RLS.
Elevated levels of total plasma homocysteine may indeed play an
etiologic role in uremic RLS. Furthermore, it appears that bad
sleep quality in RLS-affected as well as in non-RLS affected
patients on hemodialysis is associated with higher parathormone
levels. Further investigations need to be carried out to verify
these relations. | de |