title: The influence of socio-economic status and multimorbidity patterns on healthcare costs: a six-year follow-up under a universal healthcare system.
abstract: BACKGROUND
  Multimorbidity has been linked to elevated healthcare utilization and previous studies have found that socioeconomic status is an important factor associated with multimorbidity. Nonetheless, little is known regarding the impact of multimorbidity and socioeconomic status on healthcare costs and whether inequities in healthcare exist between socioeconomic classes within a universal healthcare system.
  
  
  METHODS
  This longitudinal study employed the claims database of the National Health Insurance of Taiwan (959 990 enrolees), adopting medication-based Rx-defined morbidity groups (Rx-MG) as a measurement of multimorbidity. Mixed linear models were used to estimate the effects of multimorbidity and socioeconomic characteristics on annual healthcare costs between 2005 and 2010.
  
  
  RESULTS
  The distribution of Rx-MGs and total costs presented statistically significant differences among gender, age groups, occupation, and income class (p < .001). Nearly 80% of the enrolees were classified as multimorbid and low income earners presented the highest prevalence of multimorbidity. After controlling for age and gender, increases in the number of Rx-MG assignments were associated with higher total healthcare costs. After controlling for the effects of Rx-MG assignment and demographic characteristics, physicians, paramedical personnel, and public servant were found to generate higher total costs than typical employees/self-employed enrolees, while low-income earners generated lower costs. High income levels were also found to be associated with lower total costs. It was also revealed that occupation and multimorbidity have a moderating effect on healthcare cost.
  
  
  CONCLUSIONS
  Increases in the prevalence of multimorbidity are associated with higher health care costs. This study determined that instances of multimorbidity varied according to socioeconomic class; likewise there were inequities in healthcare utilization among individuals of various occupations and income levels, even when demographic characteristics and multimorbidity were controlled for. This highlights the importance of socioeconomic status with regard to healthcare utilization. These results indicate that socioeconomic factors should not be discounted when discussing the utilization of healthcare by patients with multimorbidity.
authors: Institute of Health Policy and Management, College of Public Health, National Taiwan University, Taipei City, Taiwan.
authors: Raymond N
authors: RN
authors: Kuo
authors: Mei-Shu
authors: MS
authors: Lai
mesh_terms: D000328:Adult; D000368:Aged; D015897:Comorbidity; D016208:Databases, Factual; D005260:Female; D005500:Follow-Up Studies; D017048:Health Care Costs / Q000706:statistics & numerical data*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009313:National Health Programs / Q000191:economics*; D012923:Social Class; D013624:Taiwan; D055815:Young Adult
references: Lancet. 2012 Jul 7;380(9836):37-43
references: 22579043
references: Fam Pract. 2009 Apr;26(2):79-80
references: 19287000
references: J Gerontol A Biol Sci Med Sci. 2011 Mar;66(3):301-11
references: 21112963
references: Eur J Public Health. 2004 Sep;14(3):311-3
references: 15369040
references: Ann Fam Med. 2012 Mar-Apr;10(2):142-51
references: 22412006
references: BMC Public Health. 2012 Mar 19;12:201
references: 22429338
references: J Gen Intern Med. 2001 Aug;16(8):519-24
references: 11556927
references: Ageing Res Rev. 2011 Sep;10(4):430-9
references: 21402176
references: Am J Public Health. 2008 Jul;98(7):1198-200
references: 18511722
references: Am J Public Health. 1992 Jun;82(6):816-20
references: 1585961
references: Med Care. 2003 Jan;41(1):84-99
references: 12544546
references: Am J Manag Care. 2009 Jan;15(1):41-8
references: 19146363
references: Lancet. 2008 Nov 8;372(9650):1661-9
references: 18994664
references: Med Care. 2001 Nov;39(11):1188-202
references: 11606873
references: Int J Health Serv. 1992;22(3):429-45
references: 1644507
references: BMC Health Serv Res. 2008 Jan 18;8:14
references: 18205916
references: Health Serv Res. 1991 Apr;26(1):53-74
references: 1901841
references: Am J Epidemiol. 2001 Nov 1;154(9):854-64
references: 11682368
references: Fam Pract. 2011 Oct;28(5):516-23
references: 21436204
references: Soc Sci Med. 2008 Jul;67(2):330-40
references: 18440111
references: BMC Public Health. 2011 May 14;11:313
references: 21569558
references: J Clin Epidemiol. 2004 Feb;57(2):131-41
references: 15125622
references: Health Policy. 2011 Nov;103(1):3-8
references: 21963153
references: Soc Psychiatry Psychiatr Epidemiol. 2011 Apr;46(4):351
references: 21076915
references: J Clin Epidemiol. 1999 Jun;52(6):551-7
references: 10408995
references: BMC Health Serv Res. 2010 May 17;10:126
references: 20478026
references: Ann Fam Med. 2012 Mar-Apr;10(2):134-41
references: 22412005
references: J Clin Epidemiol. 2011 Oct;64(10):1109-17
references: 21454049
references: BMC Health Serv Res. 2010 May 06;10:111
references: 20459621
references: JAMA. 2005 Dec 14;294(22):2879-88
references: 16352796
references: Med Care. 2011 Nov;49(11):1031-9
references: 21945973
references: BMC Health Serv Res. 2012 Apr 03;12:89
references: 22471952
references: J Clin Epidemiol. 2004 Oct;57(10):1040-8
references: 15528055
references: Am J Manag Care. 2006 Feb;12(2):110-9
references: 16464140
references: Arch Intern Med. 2002 Nov 11;162(20):2269-76
references: 12418941
references: Soc Sci Med. 2000 Jun;50(11):1679-93
references: 10795973
references: Med Care. 2005 Jan;43(1):34-43
references: 15626932