title: Observed and expected frequency of comorbid chronic diseases in rheumatic patients.
abstract: OBJECTIVE
  To estimate and compare the observed and expected prevalence of the co-existence of rheumatic diseases (RD) with other chronic conditions.
  
  
  METHODS
  The self-reported diagnosis of chronic conditions was obtained from the 2192 participants in a national health survey (Spain, 1999-2000) We compared the estimated prevalence of the co-existence of a RD with other chronic conditions, to the expected prevalence using two-sample test of proportion.
  
  
  RESULTS
  The observed (O) prevalence was significantly higher than expected (E) in the following combination of self-reported diseases: RD+arterial hypertension (O/E ratio = 1.88), RD+diabetes mellitus (O/E ratio = 2.07), RD+hypercholesterolemia (O/E ratio = 1.87), RD+cardiological (O/E ratio = 1.83), and RD+digestive diseases (O/E ratio = 2.07). The prevalence of selected co-existent pairs of diseases is more frequent with increasing age and differs between women and men.
  
  
  CONCLUSIONS
  The excess in prevalence of some combinations of diseases may serve as a reminder to the rheumatologists that many of their patients will have co-existent disease of which they need to be aware to properly plan their management. It may also be a sign of common risk factors between diseases or of adverse events.
authors.affiliation: Rheumatology Unit, Hospital Clínico San Carlos, Madrid, Spain.
authors.forename: E
authors.initials: E
authors.lastname: Loza
authors.forename: J A
authors.initials: JA
authors.lastname: Jover
authors.forename: L
authors.initials: L
authors.lastname: Rodriguez-Rodriguez
authors.forename: L
authors.initials: L
authors.lastname: Carmona
mesh_terms: D000328:Adult; D017677:Age Distribution; D002318:Cardiovascular Diseases / Q000453:epidemiology; D002908:Chronic Disease / Q000453:epidemiology*; D015897:Comorbidity; D003920:Diabetes Mellitus / Q000453:epidemiology; D004066:Digestive System Diseases / Q000453:epidemiology; D005260:Female; D006306:Health Surveys; D006801:Humans; D006937:Hypercholesterolemia / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D012216:Rheumatic Diseases / Q000453:epidemiology*; D017678:Sex Distribution; D013030:Spain / Q000453:epidemiology