title: Prevalence of measured and reported multimorbidity in a representative sample of the Swiss population.
abstract: BACKGROUND
  Little is known on the prevalence of multimorbidity (MM) in the general population. We aimed to assess the prevalence of MM using measured or self-reported data in the Swiss population.
  
  
  METHODS
  Cross-sectional, population-based study conducted between 2003 and 2006 in the city of Lausanne, Switzerland, and including 3714 participants (1967 women) aged 35 to 75 years. Clinical evaluation was conducted by thoroughly trained nurses or medical assistants and the psychiatric evaluation by psychologists or psychiatrists. For psychiatric conditions, two definitions were used: either based on the participant's statements, or on psychiatric evaluation. MM was defined as presenting ≥2 morbidities out of a list of 27 (self-reported - definition A, or measured - definition B) or as the Functional Comorbidity Index (FCI) using measured data - definition C.
  
  
  RESULTS
  The overall prevalence and (95% confidence interval) of MM was 34.8% (33.3%-36.4%), 56.3% (54.6%-57.9%) and 22.7% (21.4%-24.1%) for definitions A, B and C, respectively. Prevalence of MM was higher in women (40.2%, 61.7% and 27.1% for definitions A, B and C, respectively, vs. 28.7%, 50.1% and 17.9% in men, p < 0.001); Swiss nationals (37.1%, 58.8% and 24.8% for definitions A, B and C, respectively, vs. 31.4%, 52.3% and 19.7% in foreigners, all p < 0.001); elderly (>65 years: 67.0%, 70.0% and 36.7% for definitions A, B and C, respectively, vs. 23.6%, 50.2% and 13.8% for participants <45 years, p < 0.001); participants with lower educational level; former smokers and obese participants. Multivariate analysis confirmed most of these associations: odds ratio (95% Confidence interval) 0.55 (0.47-0.64), 0.61 (0.53-0.71) and 0.51 (0.42-0.61) for men relative to women for definitions A, B and C, respectively; 1.27 (1.09-1.49), 1.29 (1.11-1.49) and 1.41 (1.17-1.71) for Swiss nationals relative to foreigners, for definitions A, B and C, respectively. Conversely, no difference was found for educational level for definitions A and B and abdominally obese participants for all definitions.
  
  
  CONCLUSIONS
  Prevalence of MM is high in the Lausanne population, and varies according to the definition or the data collection method.
authors.affiliation: Department of medicine, Internal Medicine, University Hospital of Lausanne (CHUV), Rue du Bugnon 46, 1011, Lausanne, Switzerland. Basile.Pache@unil.ch.
authors.forename: Basile
authors.initials: B
authors.lastname: Pache
authors.affiliation: Department of medicine, Internal Medicine, University Hospital of Lausanne (CHUV), Rue du Bugnon 46, 1011, Lausanne, Switzerland. Peter.Vollenweider@chuv.ch.
authors.forename: Peter
authors.initials: P
authors.lastname: Vollenweider
authors.affiliation: Department of medicine, Internal Medicine, University Hospital of Lausanne (CHUV), Rue du Bugnon 46, 1011, Lausanne, Switzerland. Gerard.Waeber@chuv.ch.
authors.forename: Gérard
authors.initials: G
authors.lastname: Waeber
authors.affiliation: Department of medicine, Internal Medicine, University Hospital of Lausanne (CHUV), Rue du Bugnon 46, 1011, Lausanne, Switzerland. Pedro-Manuel.Marques-Vidal@chuv.ch.
authors.forename: Pedro
authors.initials: P
authors.lastname: Marques-Vidal
mesh_terms: D000328:Adult; D000368:Aged; D015897:Comorbidity; D003430:Cross-Sectional Studies; D054242:Emigrants and Immigrants / Q000706:statistics & numerical data; D005006:Ethnicity; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D016017:Odds Ratio; D015995:Prevalence; D057566:Self Report; D013557:Switzerland / Q000453:epidemiology