title: Expansion or compression of multimorbidity? 10-year development of life years spent in multimorbidity based on health insurance claims data of Lower Saxony, Germany.
abstract: OBJECTIVE
  Our study examined how life years spent in multimorbidity changed over a period of 10 years (2005-2014) and whether morbidity expansion or compression has taken place. There is a little evidence on whether life years gained due to increasing life expectancy are spent in good health, or if they are accompanied by morbidity expansion.
  
  
  METHODS
  The analyses are based on German administrative claims data. Multimorbidity was defined as a combination of at least six chronic conditions and polypharmacy. After having estimated age-standardized prevalence, time trends for life years with and without multimorbidity, and the proportion of life years spent in multimorbidity (morbidity ratio) were estimated.
  
  
  RESULTS
  Prevalence proportions of multimorbidity rose continuously. Increasing life expectancies were accompanied by increasing life years with multimorbidity, decreasing multimorbidity-free life years, and by an increasing morbidity ratio.
  
  
  CONCLUSIONS
  The lifespan spent in multimorbidity was increasing over time. Our findings indicate a growing burden of multimorbidity and an increasing proportion of life years with multiple chronic conditions. It can be concluded that an expansion of morbidity in absolute and in relative terms has occurred. The findings stress the importance of prevention, healthy lifestyles, and improved medical care strategies meeting the specific requirements of patients with multimorbidity.
authors.affiliation: Medical Sociology Unit, Hannover Medical School, Hanover, Germany. Tetzlaff.Juliane@mh-hannover.de.
authors.forename: Juliane
authors.initials: J
authors.lastname: Tetzlaff
authors.affiliation: Medical Sociology Unit, Hannover Medical School, Hanover, Germany.
authors.forename: Denise
authors.initials: D
authors.lastname: Muschik
authors.affiliation: Medical Sociology Unit, Hannover Medical School, Hanover, Germany.
authors.forename: Jelena
authors.initials: J
authors.lastname: Epping
authors.affiliation: AOK Niedersachsen-Statutory Health Insurance of Lower Saxony, Hanover, Germany.
authors.forename: Sveja
authors.initials: S
authors.lastname: Eberhard
authors.affiliation: Medical Sociology Unit, Hannover Medical School, Hanover, Germany.
authors.forename: Siegfried
authors.initials: S
authors.lastname: Geyer
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002908:Chronic Disease / Q000453:epidemiology*; D005260:Female; D005858:Germany / Q000453:epidemiology; D006801:Humans; D007348:Insurance, Health / Q000706:statistics & numerical data; D008017:Life Expectancy; D008297:Male; D008875:Middle Aged; D000076322:Multimorbidity; D019338:Polypharmacy
keywords: Compression; Expansion; Multimorbidity; Prevalence; Time trend