To characterize long-term prescriptions for commonly prescribed anxiolytic benzodiazepines to veteran patients and to identify factors associated with high daily doses, we analyzed the linked pharmacy and administrative databases from New England Veterans Healthcare System (VISN 1). We analyzed treatment episodes of 3 months or longer with the 4 most commonly prescribed agents: alprazolam, clonazepam, diazepam, and lorazepam. Descriptive statistics and univariate and multivariate analyses described the sample and tested associations of pharmacological and clinical variables for patients prescribed the top 5% of average daily doses ("high-dose" prescriptions). From 16,630 full or partial treatment episodes for all 4 agents analyzed within a 42-month window, average daily doses were predominantly moderate, age-sensitive, and stable; refill lag intervals were short. Patients on "high-dose" prescriptions for the 4 agents combined, compared with "middle quartile" dose prescriptions, in adjusted analyses, were younger, more likely to have posttraumatic stress disorder (odds ratio [OR], 2.6; 95% confidence interval [CI], 2.17-3.13), substance abuse (OR, 1.50; 95% CI, 1.25-1.80), and anxiety (OR, 1.33; 95% CI, 1.11-1.60) and were more likely to be receiving concurrent oxycodone/acetaminophen (OR, 2.05; 95% CI, 1.64-2.56), anxiolytic benzodiazepine (OR, 1.51; 95% CI, 1.12-2.03), antidepressant (OR, 2.15; 95% CI, 1.80-2.58), and neuroleptic (OR, 2.03; 95% CI, 1.69-2.44) prescriptions. These results indicate that veteran patients prescribed anxiolytic benzodiazepines typically receive modest, nonincreasing doses over long-term treatment episodes. However, those on the highest average daily doses, typically more than recommended guidelines, are more likely to have clinical diagnoses and concurrent prescriptions for psychoactive medications indicative of more complex and, perhaps, problematic management.
*Pharmacoepidemiology Research Group Massachusetts Veterans Epidemiology Research and Information Center, VA Boston Healthcare System and †Boston University School of Public Health, Boston, MA.
Funding for the study is through the Massachusetts Veterans Epidemiology Research and Information Center from the Veterans Health Administration Cooperative Studies Program.
The article was presented at the 20th International Conference on Pharmacoepidemiology and Therapeutic Risk Management; August 22-25, 2004; Bordeaux, France.
Received October 25, 2004; accepted after revision June 17, 2005.
Address correspondence and reprint requests to John A. Hermos, MD, Massachusetts Veterans Epidemiology Research and Information Center (151MAV) VA, Boston Healthcare System, 150 S Huntington Avenue, Boston, MA 02130. E-mail: firstname.lastname@example.org or email@example.com.