Pre-injury polypharmacy as a predictor of outcomes in trauma patients

Abstract

Background: One of the hallmarks of modern medicine is the improving management of chronic health conditions. Long-term control of chronic disease entails increasing utilization of multiple medications and resultant polypharmacy. The goal of this study is to improve our understanding of the impact of polypharmacy on outcomes in trauma patients 45 years and older.

Materials and methods: Patients of age ≥45 years were identified from a Level I trauma center institutional registry. Detailed review of patient records included the following variables: Home medications, comorbid conditions, injury severity score (ISS), Glasgow coma scale (GCS), morbidity, mortality, hospital length of stay (LOS), intensive care unit (ICU) LOS, functional outcome measures (FOM), and discharge destination. Polypharmacy was defined by the number of medications: 0-4 (minor), 5-9 (major), or ≥10 (severe). Age- and ISS-adjusted analysis of variance and multivariate analyses were performed for these groups. Comorbidity-polypharmacy score (CPS) was defined as the number of pre-admission medications plus comorbidities. Statistical significance was set at alpha = 0.05.

Results: A total of 323 patients were examined (mean age 62.3 years, 56.1% males, median ISS 9). Study patients were using an average of 4.74 pre-injury medications, with the number of medications per patient increasing from 3.39 for the 45-54 years age group to 5.68 for the 75+ year age group. Age- and ISS-adjusted mortality was similar in the three polypharmacy groups. In multivariate analysis only age and ISS were independently predictive of mortality. Increasing polypharmacy was associated with more comorbidities, lower arrival GCS, more complications, and lower FOM scores for self-feeding and expression-communication. In addition, hospital and ICU LOS were longer for patients with severe polypharmacy. Multivariate analysis shows age, female gender, total number of injuries, number of complications, and CPS are independently associated with discharge to a facility (all, P < 0.02).

Conclusion: Over 40% of trauma patients 45 years and older were receiving 5 or more medications at the time of their injury. Although these patients do not appear to have higher mortality, they are at increased risk for complications, lower functional outcomes, and longer hospital and intensive care stays. CPS may be useful when quantifying the severity of associated comorbid conditions in the context of traumatic injury and warrants further investigation.

Keywords: Comorbid conditions; outcome prediction; polypharmacy; trauma outcomes.

Figure 1

Relationship between patient age and polypharmacy. Patients are grouped by age (x-axis) with corresponding mean (white) and median (solid black) number of pharmacologic agents per patient

Figure 2

Patterns of pharmaceutical use in this study. The ten most common medication groups in this study, listed from the most common to the least common, are as follows: NPM^a = neuro-psychiatric medications – antidepressants, antipsychotics, anxiolytics, antiepileptic medications, agents used for Alzheimer's disease, anti-Parkinsonian agents; APA/ACA^b = antiplatelet agents/anticoagulant agents; cardiac = beta-adrenergic blockers, calcium channel blockers, antiarrhythmics, digoxin, angiotensin converting enzyme inhibitors, angiotensin receptor blockers; GI^c = gastrointestinal agents – H2 blockers, proton pump inhibitors, bowel activity modulators; L/CLA^d = lipid/cholesterol lowering agents; opioids; HR^e = hormonal replacement – thyroid hormone, estrogen, other endocrine replacement regimens; glycemic agents – both enteral and parenteral; corticosteroids – regularly scheduled steroid therapy