Exposure to potentially harmful drug-disease interactions in a national cohort of older Veterans: who is at risk?

Pugh MJ, Berlowitz DR, Starner CI, Amuan ME, Marcum ZA, Hanlon JT. Exposure to potentially harmful drug-disease interactions in a national cohort of older Veterans: who is at risk? Paper presented at: VA HSR&D National Meeting; 2011 Feb 17; National Harbor, MD.

Related HSR&D Project(s)

• IIR 06-062 – Inappropriate Drug Use for Seniors: Should VA adopt new HEDIS measures

Objectives: Potentially inappropriate prescribing in the elderly (PIPE) has been a growing concern over the past decade, but little attention has been paid to use of drugs that are contraindicated for patients with specific conditions (drug-disease interactions [Rx-DI]). Our goal was to identify the prevalence and risk factors for Rx-DI in older community-dwelling VA patients. Methods: This cross-sectional retrospective database study included VA patients 65 years and older who received VA outpatient care from October 1, 2003 to September 30, 2006. We identified drug-disease interactions in 2006 defined by the Healthcare Effectiveness Data and Information Set (HEDIS) criteria using VA pharmacy and administrative databases. This measure identified medications considered inappropriate for patients with specific conditions (anticholinergics and tricyclic antidepressants in dementia; antipsychotics, tricyclic antidepressants, and sleep agents in patients with history of falls/hip fracture; and nonsteroidal anti-inflammatory agents in patients with chronic renal failure). We examined factors associated with HEDIS Rx-DI exposure including demographic (age, sex, race), health status (medications, comorbid conditions), and access to care factors (co-payment status and utilization of VA primary and geriatric care). Results: 305,041 older veterans with dementia, falls/hip fracture, or chronic renal failure met criteria for inclusion. The one-year prevalence of HEDIS Rx-DI exposure was 15.2%; prevalence was 20.2% for dementia, 16.2% for falls, and 8.5% for chronic renal failure. Patients with psychiatric conditions were significantly more likely to have HEDIS Rx-DI exposure (OR = 1.63; 95% CI: 1.59-1.67). Hispanics and individuals with no copayments were more likely to have Rx-DI exposure than whites (OR = 1.25; 95% CI: 1.20-1.31) or those with required copayments (OR = 1.28; 95% CI: 1.25-1.33). Geriatric care was associated with lower odds of dementia and renal failure Rx-DI exposure (OR = 0.68; 95% CI: 0.64-0.71 and OR = 0.69; 95% CI: 0.62-0.77, respectively). Implications: The prevalence of Rx-DI was common in older VA outpatients, and similar to prior estimates using Medicare data. When added to other forms of PIPE, over 30% of older VA patients are at increased risk of adverse drug events from PIPE exposure. Impacts: Findings from this study and our prior research suggest that improving access to geriatric care may reduce inappropriate prescribing in older veterans.