title: Age and gender differences in the prevalence and patterns of multimorbidity in the older population.
abstract: BACKGROUND
  The coexistence of several chronic diseases in one same individual, known as multimorbidity, is an important challenge facing health care systems in developed countries. Recent studies have revealed the existence of multimorbidity patterns clustering systematically associated distinct clinical entities. We sought to describe age and gender differences in the prevalence and patterns of multimorbidity in men and women over 65 years.
  
  
  METHODS
  Observational retrospective multicentre study based on diagnostic information gathered from electronic medical records of 19 primary care centres in Aragon and Catalonia. Multimorbidity patterns were identified through exploratory factor analysis. We performed a descriptive analysis of previously obtained patterns (i.e. cardiometabolic (CM), mechanical (MEC) and psychogeriatric (PG)) and the diseases included in the patterns stratifying by sex and age group.
  
  
  RESULTS
  67.5% of the aged population suffered two or more chronic diseases. 32.2% of men and 45.3% of women were assigned to at least one specific pattern of multimorbidity, and 4.6% of men and 8% of women presented more than one pattern simultaneously. Among women over 65 years the most frequent pattern was the MEC pattern (33.3%), whereas among men it was the CM pattern (21.2%). While the prevalence of the CM and MEC patterns decreased with age, the PG pattern showed a higher prevalence in the older age groups.
  
  
  CONCLUSIONS
  Significant gender differences were observed in the prevalence of multimorbidity patterns, women showing a higher prevalence of the MEC and PG patterns, as well as a higher degree of pattern overlapping, probably due to a higher life expectancy and/or worse health. Future studies on multimorbidity patterns should take into account these differences and, therefore, the study of multimorbidity and its impact should be stratified by age and sex.
authors.affiliation: Department of Health Wellbeing and Family, Government of Aragón, Zaragoza, Spain. jmabad@aragon.es.
authors.forename: José María
authors.initials: JM
authors.lastname: Abad-Díez
authors.forename: Amaia
authors.initials: A
authors.lastname: Calderón-Larrañaga
authors.forename: Antonio
authors.initials: A
authors.lastname: Poncel-Falcó
authors.forename: Beatriz
authors.initials: B
authors.lastname: Poblador-Plou
authors.forename: José Manuel
authors.initials: JM
authors.lastname: Calderón-Meza
authors.forename: Antoni
authors.initials: A
authors.lastname: Sicras-Mainar
authors.forename: Mercedes
authors.initials: M
authors.lastname: Clerencia-Sierra
authors.forename: Alexandra
authors.initials: A
authors.lastname: Prados-Torres
mesh_terms: D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000473:pathology* / Q000523:psychology*; D002318:Cardiovascular Diseases / Q000175:diagnosis / Q000453:epidemiology; D015897:Comorbidity; D005260:Female; D006801:Humans; D008297:Male; D001523:Mental Disorders / Q000175:diagnosis / Q000453:epidemiology; D011159:Population Surveillance / Q000379:methods; D015995:Prevalence; D012189:Retrospective Studies; D012727:Sex Characteristics; D013030:Spain / Q000453:epidemiology