REDUCED OUT-OF-POCKET COSTS AND MEDICATION ADHERENCE – A POPULATION-BASED STUDY
Main Article Content
Keywords
Medication adherence; out-of-pocket payment; chronic medication; healthcare benefit programs; benefit policy
Abstract
Background: In 2007, a drug benefit plan for Seniors (SDP) was launched in Saskatchewan, Canada. SDP capped out-of-pocket costs at $15 per prescription for individuals aged 65 and older.
Objectives: To quantify the impact of the SDP on chronic medication adherence.
Methods: A retrospective cohort study was conducted for participants aged 65 or older who were eligible to the SPD, controlled by a younger group aged 40 to 64 who were ineligible. Adherence was measured over 365 days using medication possession ratio (MPR). MPRs were compared between age groups, and between pre and post SDP-launch periods. The odds ratio of optimal adherence (i.e., MPR?80%) was estimated using logistic regression models with generalized estimating equations (GEE).
Results: Between 2005 and 2009, 353,568 adherence observations were observed from 188,109 unique patients. Comparing the post-SDP period vs before, the increase in the odds of optimal medication adherence was significant (OR=1.08, 95% CI: 1.04 to 1.11) and was stronger after excluding patients already receiving medication benefits from other government programs (OR= 1.21, 95% CI: 1.16 to 1.26). The SDP was associated with improved adherence among the subgroup of prevalent medication users (OR=1.08, 95% CI: 1.04 to 1.12), but not incident users (OR=1.05, 95% CI: 0.98 to 1.13).
Conclusion: Reducing out-of-pocket medication costs for seniors was associated with small improvements in medication adherence across the population.
References
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41. Lee DS, Stitt A, Wang X, et al. Administrative hospitalization database validation of cardiac procedure codes. Med Care 2013 Apr;51(4):e22–6.
42. Gurevich Y, McFarlane A, Morris K, et al. Estimating the number of coronary artery bypass graft and percutaneous coronary intervention procedures in Canada: a comparison of cardiac registry and Canadian Institute for Health Information data sources. Can J Cardiol 2010 Aug-Sep;26(7):e249–53.
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46. Shalev V, Goldshtein I, Halpern Y, et al. Association between persistence with statin therapy and reduction in low-density lipoprotein cholesterol level: analysis of real-life data from community settings. Pharmacotherapy 2014 Jan;34(1):1–8.
47. Dragomir A, Côté R, Roy L, et al. Impact of adherence to antihypertensive agents on clinical outcomes and hospitalization costs. Med Care 2010 May;48(5):418–25.
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2. Goldman DP, Joyce GF, Zheng Y. Prescription drug cost sharing: associations with medication and medical utilization and spending and health. JAMA 2007 Jul 4;298(1):61–9.
3. Rezayatmand R, Pavlova M, Groot W. The impact of out-of-pocket payments on prevention and health-related lifestyle: a systematic literature review. Eur J Public Health 2013 Feb;23(1):74–9.
4. Choudhry NK, Avorn J, Glynn RJ, et al. Full coverage for preventive medications after myocardial infarction. N Engl J Med 2011 Dec 1;365(22):2088–97.
5. Briesacher BA, Gurwitz JH, Soumerai SB. Patients at-risk for cost-related medication nonadherence: a review of the literature. J Gen Intern Med 2007 Jun;22(6):864–71.
6. Austvoll-Dahlgren A, Aaserud M, Vist G, et al. Pharmaceutical policies: effects of cap and co-payment on rational drug use. Cochrane Database Syst Rev 2008 Jan 23;(1):CD007017.
7. Remler DK, Greene J. Cost-sharing: a blunt instrument. Annu Rev Public Health 2009;30:293–311.
8. Gibson TB, Ozminkowski RJ, Goetzel RZ. The effects of prescription drug cost sharing: a review of the evidence. Am J Manag Care 2005 Nov;11(11):730–40.
9. Choudhry NK. Copayment levels and medication adherence: less is more. Circulation 2009 Jan 27;119(3):365–7.
10. Eaddy MT, Cook CL, O’Day K, et al. How patient cost-sharing trends affect adherence and outcomes: a literature review. P T 2012 Jan;37(1):45–55.
11. Donohue JM, Zhang Y, Aiju M, et al. Impact of Medicare Part D on antidepressant treatment, medication choice, and adherence among older adults with depression. Am J Geriatr Psychiatr 2011 Dec;19(12):989–97.
12. Zhang Y, Donohue JM, Lave JR, et al. The impact of Medicare Part D on medication treatment of hypertension. Health Serv Res 2011 Feb;46(1 Pt 1):185–98.
13. Zhang Y, Lave JR, Donohue JM, et al. The impact of Medicare Part D on medication adherence among older adults enrolled in Medicare-Advantage products. Med Care 2010 May;48(5):409–17.
14. Zhang Y, Donohue JM, Lave JR, et al. The effect of Medicare Part D on drug and medical spending. N Engl J Med 2009 Jul 2;361(1):52–61.
15. Donohue JM, Zhang Y, Lave JR, et al. The Medicare drug benefit (Part D) and treatment of heart failure in older adults. Am Heart J 2010 Jul;160(1):159–65.
16. Chernew ME, Shah MR, Wegh A, et al. Impact of decreasing copayments on medication adherence within a disease management environment. Health Aff (Millwood) 2008 Jan-Feb;27(1):103–12.
17. Edited by Strom BL, Kimmel SE. Textbook of Pharmacoepidemiology. John Wiley & Sons Ltd, West Sussex, England; 2006.
18. Health Quality Council. Saskatchewan MOH Data Warehouse Overview (HQC Internal Document). Saskatoon, SK; 2013.
19. Centers for Disease Control and Prevention, USA. International Classification of Diseases, Ninth Revision (ICD-9). Atlanta, GA; 1998-2011, USA.
20. Canadian Institute for Health Information. Canadian Coding Standards for Version 2015 ICD-10-CA and CCI. Canadian Institute for Health Information, Ottawa, Toronto, Victoria; 2015.
21. Quail JM, Lix LM, Osman BA, et al. Comparing comorbidity measures for predicting mortality and hospitalization in three population-based cohorts. BMC Health Serv Res 2011 Jun 10;11:146.
22. Canadian Institute for Health Information. Discharge Abstract Database (DAD). Data Elements 2010-2011, 2010; 1–8.
23. Tulloch J, Evans B. Evaluation of the accuracy of the saskatchewan health pharmaceutical information program for determining a patient’s medication use immediately before admission. Can J Hosp Pharm 2009 Jan;62(1):21–7.
24. Varas-Lorenzo C, Castellsague J, Stang MR, et al. Positive predictive value of ICD-9 codes 410 and 411 in the identification of cases of acute coronary syndromes in the Saskatchewan Hospital automated database. Pharmacoepidemiol Drug Saf 2008 Aug;17(8):842–52.
25. Rawson NS, D’Arcy C. Assessing the validity of diagnostic information in administrative health care utilization data: experience in Saskatchewan. Pharmacoepidemiol Drug Saf 1998 Nov;7(6):389–98.
26. West SL, Richter A, Melfi CA, et al. Assessing the Saskatchewan database for outcomes research studies of depression and its treatment. J Clin Epidemiol 2000 Aug;53(8):823–31.
27. Ho PM, Rumsfeld JS, Masoudi FA, et al. Effect of medication nonadherence on hospitalization and mortality among patients with diabetes mellitus. Arch Intern Med. 2006 Sep 25;166(17):1836–41.
28. Lemstra M, Blackburn D. Nonadherence to statin therapy: discontinuation after a single fill. Can J Cardiol 2012 Sep-Oct;28(5):567–73.
29. Blackburn DF, Dobson RT, Blackburn JL, et al. Adherence to statins, beta-blockers and angiotensin-converting
enzyme inhibitors following a first cardiovascular event: a retrospective cohort study. Can J Cardiol 2005 May 1;21(6):485–8.
30. Saskatchewan Health. Drug Plan Formulary V62. Regina, SK; 2013.
31. Saskatchewan Health. Saskatchewan Drug Plan Formulary v62 Supplement Maintenance drug schedule. Regina, SK; 2013.
32. Strom BL. Pharmacoepidemiology, 4th Edition. John Wiley & Sons Ltd, West Sussex, England; 2005.
33. Donnelly LA, Morris AD, Pearson ER. Adherence in patients transferred from immediate release metformin to a sustained release formulation: a population-based study. Diabetes Obes Metab 2009 Apr;11(4):338–42.
34. Sackett DL. The hypertensive patient: 5. Compliance with therapy. Can Med Assoc J 1979 Aug 4;121(3):259–61.
35. Insull W. The problem of compliance to cholesterol altering therapy. J Intern Med 1997 Apr;241(4):317–25.
36. Avorn J, Monette J, Lacour A, et al. Persistence of use of lipid-lowering medications: a cross-national study. JAMA 1998 May 13;279(18):1458–62.
37. World Health Organization. Adherence to long-term therapies Evidence for action. World Health Organization, Geneva, Switzerland; 2003.
38. Yeaw J, Benner JS, Walt JG, et al. Comparing adherence and persistence across 6 chronic medication classes. J Manag Care Pharm 2009 Nov-Dec;15(9):728–40.
39. Wang CC, Wei D, Farley JF. Impact of monthly prescription cap on medication persistence among patients with hypertension, hyperlipidemia, or diabetes. J Manag Care Pharm 2013 Apr;19(3):258–68.
40. Petersen LA, Wright S, Normand SL, et al. Positive predictive value of the diagnosis of acute myocardial infarction in an administrative database. J Gen Intern Med 1999 Sep;14(9):555–8.
41. Lee DS, Stitt A, Wang X, et al. Administrative hospitalization database validation of cardiac procedure codes. Med Care 2013 Apr;51(4):e22–6.
42. Gurevich Y, McFarlane A, Morris K, et al. Estimating the number of coronary artery bypass graft and percutaneous coronary intervention procedures in Canada: a comparison of cardiac registry and Canadian Institute for Health Information data sources. Can J Cardiol 2010 Aug-Sep;26(7):e249–53.
43. Larsen J, Andersen M, Kragstrup J, et al. High persistence of statin use in a Danish population: compliance study 1993-1998. Br J Clin Pharmacol 2002 Apr;53(4):375–8.
44. SAS Institute INC. SAS for Windows version 9.3. Cary, NC, USA; 2011.
45. Brown M, Bussell J. Medication Adherence: WHO Cares? Mayo Clin Proc. 2011 Apr; 86(4):304–14.
46. Shalev V, Goldshtein I, Halpern Y, et al. Association between persistence with statin therapy and reduction in low-density lipoprotein cholesterol level: analysis of real-life data from community settings. Pharmacotherapy 2014 Jan;34(1):1–8.
47. Dragomir A, Côté R, Roy L, et al. Impact of adherence to antihypertensive agents on clinical outcomes and hospitalization costs. Med Care 2010 May;48(5):418–25.
48. Perreault S, Ellia L, Dragomir A, et al. Effect of statin adherence on cerebrovascular disease in primary prevention. Am J Me. 2009 Jul;122(7):647–55.
49. Grymonpre R, Cheang M, Fraser M, et al. Validity of a prescription claims database to estimate medication adherence in older persons. Med Care 2006 May;44(5):471–7.