Determinants of Periodic Limb Movements in Sleep within Patients with Restless Legs Syndrome 公开

Schultz, Jonathan Steven (2011)

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Purpose: Clinico-epidemiological surveys disagree on the correlations between the
measurements of iron metabolism and Periodic Leg Movements in Sleep (PLMS) in patients
with Restless Leg Syndrome (RLS). PLMS are a feature of RLS patients that coincide
temporally with sympathetically mediated heart rate and blood pressure elevations, and could
represent a plausible biological mechanism for some RLS-comorbidities. This study evaluated
the clinical determinants of PLMS, specifically measurements of iron metabolism in a clinical
cohort of patients enriched for RLS.

: RLS patients seen at the Emory Sleep Center with measured PLMS (n = 452) were
given a detailed questionnaire by a physician assessing health habits, RLS symptoms, and co-
morbid conditions. PLMS were measured over 5 nights with an accelerometer, one night
polysomnograph, or both. A retrospective chart review was conducted to retrieve patient data
and determine significant clinical predictors and to explore how medications affect PLMS.

Results: Total Iron Binding Capacity (TIBC) was found to be a significantly correlated with
increased number of PLMS after controlling for potential confounders. However, TIBC was not
a robust determinant in predicting categorical PLMS when taken as a binary predictor. All other
iron metabolism measures were not significantly correlated with PLMS, after controlling for
potential confounders. Exploratory analyses of medication effects showed that dopamenergics
and both groups of selective serotonin reuptake inhibitors (SSRIs), those with minimal and those
with higher norepinephrine reuptake inhibition, were significant predictors of a 4 level
categorical PLMS index, while controlling for potential confounders.

Conclusions: Prior studies have suggested that PLMS are associated with anemia and that iron
deficiency might be one way to explain increased PLMS in RLS patients. TIBC was found to be
weakly associated with increased number of PLMS, however this was not found to be a very
robust finding. The blood iron panel was not associated with the severity of PLMS in patients
with RLS. Future studies should investigate the potential of TIBC, but different biological
mechanisms should be considered to understand the underlying pathology of PLMS in patients
with RLS.

Table of Contents

Table of Contents

Introduction 1

Methods 5

Results 10

Discussion 14

Tables and Figures 18

References 27

Emory IRB Approval Letter 30

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