Skip to main content

Advertisement

SpringerLink
Log in

Impact of Medicaid Preferred Drug Lists on Therapeutic Adherence

  • Original Research
  • Published:
PharmacoEconomics Aims and scope Submit manuscript

Abstract

Objective: To estimate rates of non-adherence for statins following implementation of a preferred drug list (PDL).

Study design: A retrospective cohort study.

Methods: A difference-in-difference-in-difference approach was used to estimate the impact of a PDL on the use of statins in an Alabama Medicaid population. The PDL restricted access to certain branded medications and imposed a monthly prescription limit. The use of restricted drugs was compared with the use of unrestricted drugs in the months before and after the PDL in North Carolina (where there were no such restrictions) and Alabama. Pharmacy data from 2001 to 2005 were used to examine the effect of the Alabama PDL implemented in 2004.

Results: Following the PDL in Alabama, Medicaid beneficiaries treated with statins had an 82% higher relative odds of becoming non-adherent with statin therapy compared with North Carolina and with pre-PDL Alabama [odds ratio (OR) 1.82, 95% CI 1.57, 2.11]. Furthermore, patients taking a restricted statin were more likely to be non-adherent than unrestricted patients (OR 1.42, 95% CI 1.12, 1.80). In addition, among Medicaid beneficiaries taking a restricted statin, people aged 65 years or older were more likely to be non-adherent than their younger counterparts after the PDL (OR 1.33, 95% CI 1.02, 1.73). Fifty-one per cent of patients in the Alabama sample were non-adherent with statin therapy after the PDL, compared with 39% before. Non-adherence was 36% in North Carolina in both periods.

Conclusion: The management of heart disease and high cholesterol are important challenges, especially for low-income patients. Policy makers should be aware that access restrictions can have adverse consequences for patient adherence.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Log in via an institution

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Similar content being viewed by others

References

  1. Centers for Medicare and Medicaid Services. History of the Medicaid drug rebate program [online]. Available from URL: http://www.cms.hhs.gov/MedicaidDrugRebateDispR/downloads/mdrphistory.pdf [Accessed 2006 August 9]

  2. Kaiser Family Foundation. Prescription drug trends [online]. Available from URL: http://www.kff.org/rxdrugs/upload/3057-05.pdf [Accessed 2006 August 5]

  3. Huskamp HA, Deverka PA, Epstein AM, et al. The effect of incentive-based formularies on prescription-drug utilization and spending. N Engl J Med 2003; 349(23): 2224–32

    Article  PubMed  CAS  Google Scholar 

  4. Huskamp HA, Frank RG, McGuigan KA, et al. The impact of a three-tier formulary on demand response for prescription drugs. J Econ Managem Strategy 2005; 14(3): 729–53

    Article  Google Scholar 

  5. Joyce GF, Escarce J, Solomon MD, Goldman DP. Employer drug benefit plans and spending on prescription drugs. JAMA 2002; 288(14): 1733–9

    Article  PubMed  Google Scholar 

  6. Manning WG, Newhouse JP, Duan N, et al. health insurance and the demand for medical care: evidence from a randomized experiment. Am Econ Rev 1987; 77(3): 251–77

    PubMed  CAS  Google Scholar 

  7. Motheral B, Fairman K. Effect of a three-tier prescription copay on pharmaceutical and other medical utilization. Med Care 2001; 39(12): 1293–304

    Article  PubMed  CAS  Google Scholar 

  8. Rector TS, Finch MD, Danzon PM, et al. Effect of tiered prescription copayments on the use of preferred brand medications. Med Care 2003; 41(3): 398–406

    PubMed  Google Scholar 

  9. Ridley DB. Payments promotion and the purple pill. Duke University Working Paper. Durham: North Carolina, 2006

  10. Texas Health and Human Services Commission. Medicaid cost sharing requirements: guidance for hospital emergency departments. November 26, 2002 [online]. Available from URL: http://www.hhsc.state.tx.us/medicaid/reports/Copay_EdMaterial/hospital.pdf [Accessed 2006 August 9]

  11. Kaiser Commission on Medicaid and the Uninsured. State Medicaid outpatient prescription drug policies: findings from a national survey, 2005 update [online]. October 2005. Available from URL: http://www.kff.org/medicaid/7381.cfm [Accessed 2006 August 5]

  12. Schwarzenegger RJ. Democrats agree on drug discount plan. Los Angeles Times. August 23, 2006 [online]. Available from URL: http://www.latimes.com/news/local/la-me-drugs23aug23,0,7427411.story [Accessed 2006 August 9]

  13. Carroll NV. How effectively do managed care organizations influence prescribing and dispensing decisions? Am J Manag Care 2002; 8: 1041–54

    PubMed  Google Scholar 

  14. National Association of Chain Drug Stores. Medicaid Prescription Drug and Dispensing Limits. October 2004 [online]. Available from URL: http://www.nacds.org/user-assets/pdfs/gov_affairs/issuebriefs/Medicaid%20Prescription%20Drug%20and%20Dispensing%20Limits%20%20October%202004.pdf [Accessed 2006 August 5]

  15. Cunningham P, May J. Center for Studying Health System Change. Tracking report. Results from the Community Health Tracking Study. Number 16; August 2006

  16. Soumerai SB, Ross-Degnan D, Avorn J, et al. Effects of Medicaid drug-payment limits on admission to hospitals and nursing homes. N Engl J Med 1991; 325(15): 1072–7

    Article  PubMed  CAS  Google Scholar 

  17. Bloom B, Jacobs J. Cost effects of restricting cost-effective therapy. Med Care 1985; 23(7): 872–80

    Article  PubMed  CAS  Google Scholar 

  18. Cromwell DM, Bass EB, Steinberg EP, et al. Can restrictions on reimbursement for anti-ulcer drugs decrease Medicaid pharmacy costs without increasing hospitalizations? Health Serv Res 1999; 33(6): 1593–610

    PubMed  CAS  Google Scholar 

  19. Smalley W, Griffin M, Fought R, et al. Effect of a prior authorization requirement on the use of nonsteroidal anti-inflammatory drugs by Medicaid patients. N Engl J Med 1995; 332(24): 1612–7

    Article  PubMed  CAS  Google Scholar 

  20. Tamblyn R, Laprise R, Hanley JA, et al. Adverse events associated with prescription drug cost-sharing among poor and elderly persons. JAMA 2001; 285: 421–9

    Article  PubMed  CAS  Google Scholar 

  21. Wilson J, Axelsen K, Tang S. Medicaid prescription drug access restrictions: exploring the effect on patient persistence with hypertension medications. Am J Manag Care 2005; 11: SP27–34

    PubMed  Google Scholar 

  22. Downs JR, Clearfield M, Weis S, et al. for the AFCAPS/TexCAPS Research Group. Primary prevention of acute coronary events with lovastatin in men and women with average cholesterol levels: results of AFCAPS/TexCAPS. JAMA 1998; 279: 1615–22

    Article  PubMed  CAS  Google Scholar 

  23. Heart Protection Study Collaborative Group. MRC/BHF Heart Protection Study of cholesterol-lowering with simvastatin in 5963 people with diabetes: a randomised placebo-controlled trial. Lancet 2003; 361: 2005–16

    Article  Google Scholar 

  24. The Long-term Intervention with Pravastatin in Ischaemic Disease (LIPID) Study Group. Prevention of cardiovascular events and death with pravastatin in patients with coronary heart disease and a broad range of initial cholesterol levels. N Engl J Med 1998; 339: 1349–57

    Article  Google Scholar 

  25. Sacks FM, Pfeffer MA, Moye LA, et al. for the Cholesterol and Recurrent Events Trial Investigators. The effect of pravastatin on coronary events after myocardial infarction in patients with average cholesterol levels. N Engl J Med 1996; 335: 1001–9

    Article  PubMed  CAS  Google Scholar 

  26. The Scandinavian Simvastatin Survival Study Group. Randomised trial of cholesterol lowering in 4444 patients with coronary heart disease: the Scandinavian Simvastatin Survival Study (4S). Lancet 1994; 344: 1383–9

    Google Scholar 

  27. Shepherd J, Cobbe SM, Ford I, et al. for the West of Scotland Coronary Prevention Study Group. Prevention of coronary heart disease in men with hypercholesterolemia. N Engl J Med 1995; 333: 1301–7

    Article  PubMed  CAS  Google Scholar 

  28. American Heart Association Statistics Committee and Stroke Statistics Subcommittee. Heart disease and stroke statistics — 2006 update. Circulation 2006; 113: e85–e151

    Article  Google Scholar 

  29. Centers for Disease Control and Prevention. Profiling the causes of death in the United States. Heart disease, stroke and cancer. 2001 data [online]. Available from URL: http://www.cdc.gov/nccdphp/publications/factsheets/ChronicDisease/pdfs/Alabama.pdf [Accessed 2006 August]

  30. Benner JS, Glynn RJ, Mogun H, et al. Long-term persistence in use of statin therapy in elderly patients. JAMA 2002; 288(4): 455–61

    Article  PubMed  Google Scholar 

  31. Schultz JS, O’Donnell JC, McDonough KL, et al. Determinants of compliance with statin therapy and low-density lipoprotein cholesterol goal attainment in a managed care population. Am J Manag Care 2005; 11(5): 306–12

    PubMed  Google Scholar 

  32. Herper M. The world’s best-selling drugs. Forbes. March 16, 2004 [online]. Available from URL: http://www.forbes.com/2004/03/16/cx_mh_0316bestselling.html [Accessed 2006 August 5]

  33. Alabama Medicaid. Available from URL: http://www.medicaid.alabama.gov/programs/pharmacy_svcs/pa_overrides.aspx?tab=4 [Accessed 2006 August 5]

  34. Kaiser Family Foundation. State Medicaid fact sheets [online]. Available from URL: http://www.kff.org/mfs/index.jsp [Accessed 2006 August 5]

  35. United States Pharmacopeia. Comprehensive listing of drugs in the USP model guidelines [online]. Available from URL: http://www.usp.org/healthcareInfo/mmg/revisions.html [Accessed 2005]

  36. Card D. Do minimum wages reduce employment? a case study of California, 1987–89 Indust Labor Relat Rev 1992; 46: 38–54

    Article  Google Scholar 

  37. Gruber J. The incidence of mandated maternity benefits. Am Econ Rev 1994; 84: 622–41

    PubMed  CAS  Google Scholar 

  38. Steiner JF, Prochazka V. The assessment of refill compliance using pharmacy records: methods, validity, and applications. J Clin Epidemiol 1997; 50: 105–16

    Article  PubMed  CAS  Google Scholar 

  39. Ellis JJ, Erickson SR, Stevenson JG, et al. Suboptimal statin adherence and discontinuation in primary and secondary prevention populations. J Gen Intern Med 2004; 19: 638–45

    Article  PubMed  Google Scholar 

  40. Gibson TB, Mark TL, McGuigan K, et al. The effects of prescription drug co-payments on statin adherence. Am J Manag Care 2006; 12(9): 509–17

    PubMed  Google Scholar 

  41. US Census Bureau [online]. Available from URL: http://quickfacts.census.gov/qfd/states/ [Accessed 2006 August 5]

  42. Kaiser Family Foundation. State Medicaid fact sheets. Available from URL: http://www.kff.org/mfs/index.jsp [Accessed 2006 August 5]

  43. Fortess EE, Soumerai SB, McLaughlin TJ, Ross-Degnan D. Utilization of essential medications by vulnerable older people after a drug benefit cap: importance of mental disorders, chronic pain, and practice setting. J Am Geriatr Soc 2001; 49: 793–7

    Article  PubMed  CAS  Google Scholar 

  44. Centers for Medicare and Medicaid Services. MAX 1999 file for Alabama, released by CMS in January 2004

  45. Kaiser Commission on Medicaid and the Uninsured. Dual eligibles: Medicaid’s role for low-income medicare beneficiaries; January 2006

  46. Frakt AB, Pizer SD. A first look at the new Medicare prescription drug plans. Health Affairs 2006; 25(4): 252–61

    Article  Google Scholar 

  47. Kaiser Commission on Medicaid and the Uninsured. Medicaid enrollment in 50 states, June 2004 data update; September 2005

Download references

Author information

Authors and Affiliations

  1. The Fuqua School of Business, Duke University, Box 90120, Durham, North Carolina, USA

    David B. Ridley

  2. Pfizer Inc., New York, New York, USA

    Kirsten J. Axelsen

Authors
  1. David B. Ridley
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Kirsten J. Axelsen
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding author

Correspondence to David B. Ridley.

Rights and permissions

Reprints and permissions

About this article

Cite this article

Ridley, D.B., Axelsen, K.J. Impact of Medicaid Preferred Drug Lists on Therapeutic Adherence. PharmacoEconomics 24 (Suppl 3), 65–78 (2006). https://doi.org/10.2165/00019053-200624003-00006

Download citation

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.2165/00019053-200624003-00006

Keywords

Search

Navigation