title: Implications of comorbidity for primary care costs in the UK: a retrospective observational study.
abstract: BACKGROUND
  Comorbidity is increasingly common in primary care. The cost implications for patient care and budgetary management are unclear.
  
  
  OBJECTIVE
  To investigate whether caring for patients with specific disease combinations increases or decreases primary care costs compared with treating separate patients with one condition each.
  
  
  METHODS
  Retrospective observational study using data on 86 100 patients in the General Practice Research Database.
  
  
  METHODS
  Annual primary care cost was estimated for each patient including consultations, medication, and investigations. Patients with comorbidity were defined as those with a current diagnosis of more than one chronic condition in the Quality and Outcomes Framework. Multiple regression modelling was used to identify, for three age groups, disease combinations that increase (cost-increasing) or decrease (cost-limiting) cost compared with treating each condition separately.
  
  
  RESULTS
  Twenty per cent of patients had at least two chronic conditions. All conditions were found to be both cost-increasing and cost-limiting when co-occurring with other conditions except dementia, which is only cost-limiting. Depression is the most important cost-increasing condition when co-occurring with a range of conditions. Hypertension is cost-limiting, particularly when co-occurring with other cardiovascular conditions.
  
  
  CONCLUSIONS
  Three categories of comorbidity emerge, those that are: cost-increasing, mainly due to a combination of depression with physical comorbidity; cost-limiting because treatment for the conditions overlap; and cost-limiting for no apparent reason but possibly because of inadequate care. These results can contribute to efficient and effective management of chronic conditions in primary care.
authors.affiliation: Centre for Academic Primary Care, School of Social and Community Medicine, University of Bristol, Bristol, UK.
authors.forename: Samuel L
authors.initials: SL
authors.lastname: Brilleman
authors.forename: Sarah
authors.initials: S
authors.lastname: Purdy
authors.forename: Chris
authors.initials: C
authors.lastname: Salisbury
authors.forename: Frank
authors.initials: F
authors.lastname: Windmeijer
authors.forename: Hugh
authors.initials: H
authors.lastname: Gravelle
authors.forename: Sandra
authors.initials: S
authors.lastname: Hollinghurst
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002318:Cardiovascular Diseases / Q000191:economics / Q000453:epidemiology*; D015897:Comorbidity; D017281:Cost of Illness; D003362:Cost-Benefit Analysis; D003863:Depression / Q000191:economics / Q000453:epidemiology*; D005260:Female; D005102:Health Expenditures; D006801:Humans; D006973:Hypertension / Q000191:economics / Q000453:epidemiology*; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D011320:Primary Health Care / Q000191:economics / Q000706:statistics & numerical data; D012189:Retrospective Studies; D006113:United Kingdom / Q000453:epidemiology
references.citation: Br J Gen Pract. 2011 Jan;61(582):e12-21
references.pmid: 21401985
references.citation: Fam Pract. 2011 Oct;28(5):516-23
references.pmid: 21436204
references.citation: JAMA. 2005 Aug 10;294(6):716-24
references.pmid: 16091574
references.citation: Diabetologia. 2010 Dec;53(12):2470-9
references.pmid: 20700575
references.citation: Diabetes Care. 2002 Mar;25(3):482-6
references.pmid: 11874934
references.citation: Br J Gen Pract. 2010 Mar;60(572):e128-36
references.pmid: 20202356
references.citation: BMJ. 2012 Sep 03;345:e5559
references.pmid: 22945951
references.citation: Med Care Res Rev. 2011 Aug;68(4):387-420
references.pmid: 21813576
references.citation: Diabetes Care. 2003 Feb;26(2):415-20
references.pmid: 12547872
references.citation: Ann Fam Med. 2009 Jul-Aug;7(4):357-63
references.pmid: 19597174
references.citation: Annu Rev Public Health. 2002;23:151-69
references.pmid: 11910059
references.citation: J Public Health Med. 1999 Sep;21(3):299-304
references.pmid: 10528957
references.citation: Ann Fam Med. 2006 Mar-Apr;4(2):101-3
references.pmid: 16569711
references.citation: Psychosom Med. 2007 Jul-Aug;69(6):543-50
references.pmid: 17636148
references.citation: Lancet. 2012 Jul 7;380(9836):37-43
references.pmid: 22579043
references.citation: J Gen Intern Med. 2007 Apr;22(4):464-9
references.pmid: 17372794
references.citation: BMC Gastroenterol. 2010 Mar 17;10:31
references.pmid: 20233451
references.citation: Gerontologist. 2005 Oct;45 Spec No 1(1):8-10
references.pmid: 16230744
references.citation: BMJ Qual Saf. 2011 Mar;20(3):275-81
references.pmid: 21209143
references.citation: J Health Econ. 2014 May;35:109-22
references.pmid: 24657375