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The American Journal of Managed Care March 2019
Fragmented Ambulatory Care and Subsequent Emergency Department Visits and Hospital Admissions Among Medicaid Beneficiaries
Lisa M. Kern, MD, MPH; Joanna K. Seirup, MPH; Mangala Rajan, MBA; Rachel Jawahar, PhD, MPH; and Susan S. Stuard, MBA
Incorrect and Missing Author Initials in Affiliations and Authorship Information
From the Editorial Board: Austin Frakt, PhD
Austin Frakt, PhD
Implications of Eligibility Category Churn for Pediatric Payment in Medicaid
Deena J. Chisolm, PhD; Sean P. Gleeson, MD, MBA; Kelly J. Kelleher, MD, MPH; Marisa E. Domino, PhD; Emily Alexy, MPH; Wendy Yi Xu, PhD; and Paula H. Song, PhD
Factors Influencing Primary Care Providers’ Decisions to Accept New Medicaid Patients Under Michigan’s Medicaid Expansion
Renuka Tipirneni, MD, MSc; Edith C. Kieffer, PhD, MPH; John Z. Ayanian, MD, MPP; Eric G. Campbell, PhD; Cengiz Salman, MA; Sarah J. Clark, MPH; Tammy Chang, MD, MPH, MS; Adrianne N. Haggins, MD, MSc; Erica Solway, PhD, MPH, MSW; Matthias A. Kirch, MS; and Susan D. Goold, MD, MHSA, MA
Did Medicaid Expansion Matter in States With Generous Medicaid?
Alina Denham, MS; and Peter J. Veazie, PhD
Access to Primary and Dental Care Among Adults Newly Enrolled in Medicaid
Krisda H. Chaiyachati, MD, MPH, MSHP; Jeffrey K. Hom, MD, MSHP; Charlene Wong, MD, MSHP; Kamyar Nasseh, PhD; Xinwei Chen, MS; Ashley Beggin, BS; Elisa Zygmunt, MSW; Marko Vujicic, PhD; and David Grande, MD, MPA
Medicare Annual Wellness Visit Association With Healthcare Quality and Costs
Adam L. Beckman, BS; Adan Z. Becerra, PhD; Anna Marcus, BS; C. Annette DuBard, MD, MPH; Kimberly Lynch, MPH; Emily Maxson, MD; Farzad Mostashari, MD, ScM; and Jennifer King, PhD
Common Elements in Opioid Use Disorder Guidelines for Buprenorphine Prescribing
Timothy J. Atkinson, PharmD, BCPS, CPE; Andrew J.B. Pisansky, MD, MS; Katie L. Miller, PharmD, BCPS; and R. Jason Yong, MD, MBA
Specialty Care Access for Medicaid Enrollees in Expansion States
Justin W. Timbie, PhD; Ashley M. Kranz, PhD; Ammarah Mahmud, MPH; and Cheryl L. Damberg, PhD
Currently Reading
Gender Differences in Prescribing of Zolpidem in the Veterans Health Administration
Guneet K. Jasuja, PhD; Joel I. Reisman, AB; Renda Soylemez Wiener, MD, MPH; Melissa L. Christopher, PharmD; and Adam J. Rose, MD, MSc
Health Insurance Literacy: Disparities by Race, Ethnicity, and Language Preference
Victor G. Villagra, MD; Bhumika Bhuva, MA; Emil Coman, PhD; Denise O. Smith, MBA; and Judith Fifield, PhD

Gender Differences in Prescribing of Zolpidem in the Veterans Health Administration

Guneet K. Jasuja, PhD; Joel I. Reisman, AB; Renda Soylemez Wiener, MD, MPH; Melissa L. Christopher, PharmD; and Adam J. Rose, MD, MSc
We found inappropriate prescribing of zolpidem, in terms of both guideline-discordant dosage and coprescribing with benzodiazepines, with female veterans affected more than male veterans.
Outcome Variables

In this study, we evaluated 2 outcomes relating to appropriateness of zolpidem prescribing. The first measure was whether the daily dose prescribed to male and female veterans exceeded the 2013 PBM recommended dosage (men: IR ≤10 mg or CR ≤12.5 mg; women: IR ≤5 mg or CR ≤6.25 mg). In our study, we calculated the daily dose by multiplying the inferred tablets per day (quantity divided by days’ supply) by the tablet strength given in the full description of the medication. We also examined a second measure of inappropriate prescribing in both men and women: the overlap in prescribing of zolpidem with the prescribing of a benzodiazepine. We defined overlapping prescribing as a benzodiazepine prescription for more than 3 days written within 30 days before or after the index zolpidem prescription.

Statistical Analysis

As a first step, we generated descriptive characteristics stratified by gender. We used Pearson’s χ2 test to perform statistical comparisons between men and women. We grouped age and race variables into categories to yield a reasonable frequency distribution. Physical and mental health conditions were binary (yes/no) variables. We applied a sampling weight of 10 to the nonzolpidem cases when computing prevalence and initiation. We imputed missing data on all variables except race, marital status, and comorbidities to allow inclusion of all observations in multivariate analyses. Second, we conducted an interrupted time series analysis before and after the 2013 PBM guidelines (which recommended lower zolpidem doses for women) to determine whether these guidelines led to significant improvement in appropriate zolpidem dosing. For this analysis, we excluded 1849 men and 193 women because they had incomplete dose data on the index date of their zolpidem prescription. We calculated the unadjusted proportion of male and female veterans receiving high-dose zolpidem prescriptions from 2011 to 2016. Finally, we generated multivariate logistic regression models to analyze the determinants of the 2 inappropriate prescribing outcomes, specifically dose exceeding guideline recommendations and overlap with benzodiazepines, in separate models for men and women. We used SAS version 9.4 (SAS Institute Inc; Cary, North Carolina) for all analyses. We used P <.001 as the threshold for statistical significance for all analyses.

RESULTS

Characteristics of Zolpidem Users

Table 1 reports descriptive characteristics of zolpidem users stratified by gender. Across the VHA, 7.1% of men and 10.0% of women received zolpidem at least once during the study period. Compared with male zolpidem users, female users were younger (45.7 years vs 56.6 years) and were more likely to have anxiety disorders (21.1% vs 13.1%), bipolar disorder (11.4% vs 6.1%), and major depression (44.0% vs 29.8%); P <.001 for all. Men receiving zolpidem had higher proportions of coronary artery disease (11.1% vs 1.8%), diabetes (21.0% vs 9.2%), and hypertension (38.5% vs 20.3%) compared with women; P <.001 for all.

Trends in High-Dose Zolpidem Prescribing for Men Versus Women

Unadjusted trends in high-dose zolpidem prescriptions by gender before and after the PBM 2013 recommendations for suggested lower dose in women are shown in the Figure (A and B). The observed proportion of women receiving the higher dose decreased considerably from 75.9% in 2011 to 29.1% in 2016 (P <.001), and the 2013 PBM recommendations had a significant effect after adjustment for secular trends and covariates (P <.001). For men, there was a decline in observed receipt of high-dose zolpidem from 1.7% in 2011 to 0.1% in 2016 (P <.001), but the recommendations did not have a significant effect (P = .126).

Patient Characteristics Associated With Inappropriate Zolpidem Prescribing Stratified by Gender

For our first outcome, inappropriate dose, the analysis was limited to men and women with an index prescription in January 2013 or later, resulting in a sample of 194,355 men and 28,181 women. As reported in Table 2, compared with 0.1% of men who received more than 10 mg of IR or 12.5 mg of CR, approximately 29.7% of women zolpidem users were receiving an inappropriate dosage, defined as exceeding 5 mg/day for IR or 6.25 mg/day for CR. Men with substance use disorder (adjusted odds ratio [AOR], 3.34; P <.001 for this and all other findings) and men living in the Midwest (AOR, 1.42) were more likely to receive an inappropriate zolpidem dose after adjusting for covariates. In fully adjusted models, younger women were more likely to receive an inappropriately high dose compared with women 80 years or older (AORs: 21-39 years, 2.75; 40-49 years, 2.97). Further, women with certain conditions, including major depression (AOR, 0.91), were less likely to receive an inappropriate dosage. Women in the West were less likely to receive an inappropriate dose (AOR, 0.80) compared with women residing in the Northeast. Similar to the men, women with substance use disorder were more likely to receive an inappropriately high dose of zolpidem (AOR, 1.48).

Of the 500,332 zolpidem users, 193,355 were also prescribed benzodiazepines at some point in the study period. Table 3 presents the results on the concomitant prescribing of zolpidem and benzodiazepines by gender. A higher proportion of female veterans had an overlapping benzodiazepine prescription along with their zolpidem prescription within a 30-day period (18.8% of women vs 14.3% of men). For men, there was a significant age effect with coprescribing of zolpidem and benzodiazepines, with men aged 40 to 79 years at an increased risk of this coprescribing compared with men 80 years or older (AORs: 40-49 years, 1.12; 50-59 years, 1.33; 60-69 years, 1.23; 70-79 years, 1.14) for all age categories (P < .001 for all comparisons). Conditions including cancer (AOR, 1.42), anxiety (AOR, 2.66), posttraumatic stress disorder (PTSD) (AOR, 1.47), and schizophrenia (AOR, 2.46) were also associated with overlapping prescribing for male veterans. Further, in fully adjusted models for men, sites in the South (AOR, 0.96) and West (AOR, 0.87) were less likely to prescribe overlapping doses compared with sites in the Northeast. Similarly, for women, mental health conditions such as anxiety (AOR, 2.28), bipolar disorder (AOR, 1.73), PTSD (AOR, 1.44), and schizophrenia (AOR, 2.05) were associated with overlapping prescribing of zolpidem and benzodiazepines. Regions other than the Northeast tended to be associated with less overlapping prescribing.


 
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