title: Co- and multimorbidity patterns in primary care based on episodes of care: results from the German CONTENT project.
abstract: BACKGROUND
  Due to technological progress and improvements in medical care and health policy the average age of patients in primary care is continuously growing. In equal measure, an increasing proportion of mostly elderly primary care patients presents with multiple coexisting medical conditions. To properly assess the current situation of co- and multimorbidity, valid scientific data based on an appropriate data structure are indispensable. CONTENT (CONTinuous morbidity registration Epidemiologic NeTwork) is an ambitious project in Germany to establish a system for adequate record keeping and analysis in primary care based on episodes of care. An episode is defined as health problem from its first presentation by a patient to a doctor until the completion of the last encounter for it. The study aims to describe co- and multimorbidity as well as health care utilization based on episodes of care for the study population of the first participating general practices.
  
  
  METHODS
  The analyses were based on a total of 39,699 patients in a yearly contact group (YCG) out of 17 general practices in Germany for which data entry based on episodes of care using the International Classification of Primary Care (ICPC) was performed between 1.1.2006 and 31.12.2006. In order to model the relationship between the explanatory variables (age, gender, number of chronic conditions) and the response variables of interest (number of different prescriptions, number of referrals, number of encounters) that were applied to measure health care utilization, we used multiple linear regression.
  
  
  RESULTS
  In comparison to gender, patients' age had a manifestly stronger impact on the number of different prescriptions, the number of referrals and number of encounters. In comparison to age (beta = 0.043, p < 0.0001), multimorbidity measured by the number of patients' chronic conditions (beta = 0.51, p < 0.0001) had a manifestly stronger impact the number of encounters for the observation period. Moreover, we could observe that the number of patients' chronic conditions had a significant impact on the number of different prescriptions (beta = 0.226, p < 0.0001) as well as on the number of referrals (beta = 0.3, p < 0.0001).
  
  
  CONCLUSIONS
  Documentation in primary care on the basis of episodes of care facilitates an insight to concurrently existing health problems and related medical procedures. Therefore, the resulting data provide a basis to obtain co- and multimorbidity patterns and corresponding health care utilization issues in order to understand the particular complex needs caused by multimorbidity.
authors.affiliation: Department of General Practice and Health Services Research, University of Heidelberg, Germany. gunter.laux@med.uni-heidelberg.de
authors.forename: Gunter
authors.initials: G
authors.lastname: Laux
authors.forename: Thomas
authors.initials: T
authors.lastname: Kuehlein
authors.forename: Thomas
authors.initials: T
authors.lastname: Rosemann
authors.forename: Joachim
authors.initials: J
authors.lastname: Szecsenyi
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002908:Chronic Disease / Q000453:epidemiology*; D015897:Comorbidity; D017050:Episode of Care; D005260:Female; D005858:Germany / Q000453:epidemiology; D006801:Humans; D020407:Internet; D008297:Male; D016347:Medical Records Systems, Computerized; D008875:Middle Aged; D010865:Pilot Projects; D011320:Primary Health Care / Q000706:statistics & numerical data*; D012984:Software