title: Prevalence of orthostatic hypotension in Parkinson's disease: a systematic review and meta-analysis.
abstract: BACKGROUND
  Although orthostatic hypotension (OH) is recognized as one of the main non-motor symptoms of Parkinson's disease (PD), there is inconsistent evidence about the prevalence of OH in PD. To estimate the prevalence of OH in PD more precisely we conducted a systematic review of the literature.
  
  
  METHODS
  From PubMed and Embase searches with predefined inclusion criteria, we identified studies published up till December 2009. Prevalence numbers from studies were pooled using a non-linear random-effects meta-analysis.
  
  
  RESULTS
  We found 25 studies from which the prevalence of OH could be calculated. The pooled estimate of the point prevalence of OH in PD was 30.1% (95% CI: 22.9% to 38.4%). We found a large statistical heterogeneity between studies which could not be reduced by several subgroup analyses.
  
  
  CONCLUSIONS
  The estimated prevalence of OH in PD is 30%. However, due to the large heterogeneity between studies this pooled estimate should be interpreted with caution. More data from unselected population-based cohorts are needed.
authors.affiliation: Department of Neurology, Academic Medical Center, Amsterdam, The Netherlands.
authors.forename: Daan C
authors.initials: DC
authors.lastname: Velseboer
authors.forename: Rob J
authors.initials: RJ
authors.lastname: de Haan
authors.forename: Wouter
authors.initials: W
authors.lastname: Wieling
authors.forename: David S
authors.initials: DS
authors.lastname: Goldstein
authors.forename: Rob M A
authors.initials: RM
authors.lastname: de Bie
mesh_terms: D006801:Humans; D007024:Hypotension, Orthostatic / Q000453:epidemiology* / Q000209:etiology*; D010300:Parkinson Disease / Q000150:complications*; D015995:Prevalence