Association Between Dual Use of Department of Veterans Affairs and Medicare Part D Drug Benefits and Potentially Unsafe Prescribing | Clinical Pharmacy and Pharmacology | JAMA Internal Medicine | JAMA Network
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Figure.  Probability of Potentially Unsafe Medication (PUM) Exposure
Probability of Potentially Unsafe Medication (PUM) Exposure

Exposure to PUM was measured as any prescription for a Healthcare Effectiveness Data and Information Set high-risk medication in the elderly (PUM-HEDIS), prescriptions with an anticholinergic cognitive burden score of at least 3 indicating any daily exposure (PUM-ACB), and any overlapping days of exposure to drug-drug interactions (PUM-DDI). The proportion of total prescriptions from the Department of Veterans Affairs (VA) was measured as total VA prescriptions divided by total VA plus Medicare Part D prescriptions. A proportion of 0.50 indicates 50% from the VA and 50% from Part D (shaded area).

Table.  Adjusted Use of PUM Among Older Veterans in 2015 by VA-Only vs Dual VA–Medicare Part D Usea
Adjusted Use of PUM Among Older Veterans in 2015 by VA-Only vs Dual VA–Medicare Part D Usea
1.
Thorpe  JM, Thorpe  CT, Gellad  WF,  et al.  Dual health care system use and high-risk prescribing in patients with dementia: a national cohort study.  Ann Intern Med. 2017;166(3):157-163. doi:10.7326/M16-0551PubMedGoogle ScholarCrossref
2.
Gellad  WF, Thorpe  JM, Zhao  X,  et al.  Impact of dual use of Department of Veterans Affairs and Medicare Part D drug benefits on potentially unsafe opioid use.  Am J Public Health. 2018;108(2):248-255. doi:10.2105/AJPH.2017.304174PubMedGoogle ScholarCrossref
3.
Pharmacy Quality Alliance. Medication safety: PQA medication safety measures. Drug-drug interactions (2017 update) (DDI-2017). February 19, 2019. https://www.pqaalliance.org/medication-safety. Updated August 28, 2018. Accessed February 19, 2019.
4.
Hainmueller  J, Xu  Y.  Ebalance: a Stata package for entropy balancing.  J Stat Softw. 2013;54(7):1-18. doi:10.18637/jss.v054.i07Google ScholarCrossref
5.
Sisk  R. Trump signs $55 billion bill to replace VA Choice Program. https://www.military.com/daily-news/2018/06/06/trump-signs-55-billion-bill-replace-va-choice-program.html. Posted June 6, 2018. Accessed March 2, 2019.
6.
Centers for Medicare & Medicaid Services. The 2008 Annual Report of the Boards of Trustees of the Federal Hospital Insurance and Federal Supplementary Medical Insurance Trust Funds. https://www.cms.gov/Research-Statistics-Data-and-Systems/Statistics-Trends-and-Reports/ReportsTrustFunds/downloads/tr2008.pdf. March 25, 2008. Accessed March 15, 2019.
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    Research Letter
    Health Care Policy and Law
    July 22, 2019

    Association Between Dual Use of Department of Veterans Affairs and Medicare Part D Drug Benefits and Potentially Unsafe Prescribing

    Author Affiliations
    • 1Center for Health Equity Research and Promotion, Veterans Affairs Pittsburgh Healthcare System, Pittsburgh, Pennsylvania
    • 2Division of Pharmaceutical Outcomes and Policy, UNC-Chapel Hill Eshelman School of Pharmacy, Chapel Hill, North Carolina
    • 3Department of Pharmacy and Therapeutics, School of Pharmacy, University of Pittsburgh, Pittsburgh, Pennsylvania
    • 4Corporal Michael J. Crescenz Veterans Affairs Medical Center and the Center for Health Equity Research and Promotion, Philadelphia, Pennsylvania
    • 5Division of General Internal Medicine, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania
    • 6Center Center of Innovation to Accelerate Discovery and Practice Transformation, Durham Veterans Affairs Health Care System Durham, North Carolina
    • 7Department of Population Health Sciences, Duke University School of Medicine, Durham, North Carolina
    JAMA Intern Med. 2019;179(11):1584-1586. doi:10.1001/jamainternmed.2019.2788

    Veterans 65 years and older with prescription drug benefits from the Department of Veterans Affairs (VA) are almost universally eligible for Medicare Part D (hereinafter referred to as Part D). Although dual eligibility may increase access to necessary medications, receiving prescriptions from 2 systems (dual use) may also fragment care and undermine prescribing safety. Previous work showed that dual VA–Part D prescription drug use is a risk factor for potentially unsafe medication (PUM) exposure in veterans with dementia1 and opioid users.1,2 However, whether these risks generalize to the entire Medicare-covered population of older VA users remains unknown. We evaluated the association of dual prescription use through the VA and Part D (vs VA-only use) with the prevalence of PUM exposure in a national cohort of dually eligible older veterans.

    Methods

    We linked national VA and Part D records of use of health care services and prescriptions in a cohort of 279 940 veterans who were continuously enrolled in VA and Part D and received at least 1 medication through the VA in 2015. We further limited the study to veterans 68 years or older on January 1, 2015.1 We categorized these veterans as dual users (ie, ≥1 medication from the VA and Part D) or VA-only users. This study followed the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) reporting guidelines. This study was approved by the institutional review board of the VA, which waived the need for informed consent.

    Dates of administrative health care data use and analysis ranged from January 1, 2012, through December 31, 2015. We examined 4 previously validated PUM measures in 2015: any prescription for a Healthcare Effectiveness Data and Information Set high-risk medication in the elderly (PUM-HEDIS); any exposure to prescriptions with an anticholinergic cognitive burden score of at least 3 (PUM-ACB); any overlapping days of exposure to drug combinations with high risk for severe interactions (PUM-DDI); and a composite measure of any type of PUM exposure.3 We also examined an alternative definition of dual use: the proportion of total prescriptions (VA plus Part D) received from the VA in 2015. Several covariates differed at baseline. We used entropy balancing to achieve covariate balance.4 Unlike propensity weighting, entropy balance weighting directly adjusts the weights to sample means and variances, reducing the effect of model misspecification (Table).

    Results

    Among 279 940 Medicare-eligible older veterans receiving a prescription from the VA, 18.9% (95% CI, 18.7%-19.0%) were dual users and 44.3% (95% CI, 37.3%-51.4%) were exposed to at least 1 PUM in 2015. Among dual users, 49.7% (95% CI, 49.2%-50.0%) were exposed to any PUM type, including 38.6% (95% CI, 38.2%-39.0%) to PUM-ACB, 19.3% (95% CI, 18.9%-19.6%) to PUM-HEDIS, and 4.4% (95% CI, 4.2%-4.6%) to PUM-DDI.

    In adjusted results, dual use was associated with increased odds of any PUM exposure (adjusted odds ratio [aOR], 1.84; 95% CI, 1.80-1.88) and an additional 19.4 days of exposure (95% CI, 18.1-20.8 days) (Table). Dual use was also associated with increased odds of PUM-HEDIS (aOR, 1.82; 95% CI, 1.77-1.88), PUM-ACB (aOR, 1.53; 95% CI, 1.50-1.57), and PUM-DDI (aOR, 3.25; 95% CI, 3.02-3.48). Dual use measured as the proportion of total 2015 prescriptions from the VA revealed that PUM exposure was lowest among VA-only users, and PUM exposure peaked in veterans receiving prescriptions in near-equal proportions (50:50) from the VA and Part D (Figure).

    Discussion

    Dual use of VA and Part D prescription drug benefits was associated with an almost 2-fold increase in the odds of exposure to any PUM compared with VA-only use and more than 3 times the odds of exposure to severe drug-drug interactions. Despite the limitations of observational studies, our results show that the prescribing safety risks associated with dual VA–Part D use are not limited to high-risk subgroups.1,2 Policies that increase veterans’ access to non-VA health care professionals therefore may unintentionally jeopardize patient safety. Furthermore, it is possible that the safety risks found in this study of veterans may extend to all patients who receive prescriptions across disconnected health care providers or systems. To mitigate these potential risks, policies intended to expand access to non-VA providers must ensure patient information is shared and integrated into routine practice for all patients seeking care across multiple health care systems.5,6

    Back to top
    Article Information

    Accepted for Publication: May 23, 2019.

    Corresponding Author: Joshua M. Thorpe, PhD, MPH, Division of Pharmaceutical Outcomes and Policy, UNC-Chapel Hill Eshelman School of Pharmacy, 301 Pharmacy Ln, Chapel Hill, NC 27599 (joshua.thorpe@unc.edu).

    Published Online: July 22, 2019. doi:10.1001/jamainternmed.2019.2788

    Author Contributions: Dr Thorpe and Mr Cashy had full access to all the data in the study and take responsibility for the integrity of the data and the accuracy of the data analysis.

    Concept and design: JM Thorpe, CT Thorpe, Carico, Van Houtven.

    Acquisition, analysis, or interpretation of data: All authors.

    Drafting of the manuscript: JM Thorpe, Cashy.

    Critical revision of the manuscript for important intellectual content: JM Thorpe, CT Thorpe, Schleiden, Carico, Gellad, Van Houtven.

    Statistical analysis: JM Thorpe, Cashy, Carico.

    Obtained funding: JM Thorpe, CT Thorpe.

    Administrative, technical, or material support: JM Thorpe, CT Thorpe, Schleiden, Van Houtven.

    Supervision: JM Thorpe.

    Conflict of Interest Disclosures: Dr JM Thorpe reported receiving a research grant from the Department of Veterans Affairs (VA) during the conduct of the study. Dr CT Thorpe reported receiving grants from the VA during the conduct of the study and grants from the VA, the Donaghue Foundation, and the Vasculitis Foundation outside the submitted work. Dr Gellad reported receiving grants from the VA during the conduct of the study. Dr Van Houtven reported receiving grants from the VA Health Services Research and Development Service (HSR&D) and the National Institutes of Health during the conduct of the study. No other disclosures were reported.

    Funding/Support: This study was supported by the Merit Award IIR 12-379 from the VA HSR&D. Dr Carico was supported by a postdoctoral fellowship from the VA Office of Academicc Affiliations.

    Role of the Funder/Sponsor: The sponsor had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, or approval of the manuscript; and decision to submit the manuscript for publication.

    Additional Contributions: Joseph T. Hanlon, PharmD, MS, and Maria K. Mor, PhD, were compensated for intellectual contributions made to the original grant. Chester B. Good, MD, contributed to the intellectual content of the original grant but, as a VA physician, was not compensated.

    References
    1.
    Thorpe  JM, Thorpe  CT, Gellad  WF,  et al.  Dual health care system use and high-risk prescribing in patients with dementia: a national cohort study.  Ann Intern Med. 2017;166(3):157-163. doi:10.7326/M16-0551PubMedGoogle ScholarCrossref
    2.
    Gellad  WF, Thorpe  JM, Zhao  X,  et al.  Impact of dual use of Department of Veterans Affairs and Medicare Part D drug benefits on potentially unsafe opioid use.  Am J Public Health. 2018;108(2):248-255. doi:10.2105/AJPH.2017.304174PubMedGoogle ScholarCrossref
    3.
    Pharmacy Quality Alliance. Medication safety: PQA medication safety measures. Drug-drug interactions (2017 update) (DDI-2017). February 19, 2019. https://www.pqaalliance.org/medication-safety. Updated August 28, 2018. Accessed February 19, 2019.
    4.
    Hainmueller  J, Xu  Y.  Ebalance: a Stata package for entropy balancing.  J Stat Softw. 2013;54(7):1-18. doi:10.18637/jss.v054.i07Google ScholarCrossref
    5.
    Sisk  R. Trump signs $55 billion bill to replace VA Choice Program. https://www.military.com/daily-news/2018/06/06/trump-signs-55-billion-bill-replace-va-choice-program.html. Posted June 6, 2018. Accessed March 2, 2019.
    6.
    Centers for Medicare & Medicaid Services. The 2008 Annual Report of the Boards of Trustees of the Federal Hospital Insurance and Federal Supplementary Medical Insurance Trust Funds. https://www.cms.gov/Research-Statistics-Data-and-Systems/Statistics-Trends-and-Reports/ReportsTrustFunds/downloads/tr2008.pdf. March 25, 2008. Accessed March 15, 2019.
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