Association between potentially inappropriate medication use in elderly adults and hospital-related outcomes.

Abstract

To the Editor: The Beers Criteria, which were updated in 2012 with support from the American Geriatrics Society, identify 34 potentially inappropriate medications (PIMs), independent of diagnoses, to avoid in individuals aged 65 and older.1 Prior research regarding the effect of PIMs on health outcomes has focused on community and nursing home settings, and data from hospitalized individuals are minimal.2-6 The objective of the current study was to evaluate the association between the inpatient use of PIMs and hospital outcomes. Participants were individuals aged 65 and older admitted to the hospital between May 2012 and April 2013 with a primary International Classification of Diseases, Ninth Revision, code of pneumonia, acute myocardial infarction, or heart failure. Individuals admitted for observation, as outpatients, or to a surgical or intensive care service were excluded. Participants were categorized into four groups based on the number of PIMs prescribed during the index hospitalization using the 2012 Beers Criteria, independent of diagnosis. Categorical variables were evaluated using the chi-square test and continuous variables using analysis of variance between the four PIM categories. Four outcomes were evaluated: 30-day length of hospital stay (length of the index admission plus length of any readmission that occurred within 30 days), length of stay, total hospital costs, and 30-day readmission rate. Multivariate logistic regression and multivariate general linear models were assembled to evaluate the outcomes, using one PIM as the reference in all cases. Statistical analyses were conducted using SPSS version 21 for Windows (IBM/SPSS, Inc., Chicago, IL). Of 560 participants, 53% were male, 81% were Caucasian, 32% were aged 85 and older, and 68% had a mild burden of disease according to Charlson score; 46% were admitted for HF, 33% for myocardial infarction, and 21% for pneumonia. Six hundred forty-eight PIMs were prescribed to 380 participants, with the most common being sliding scale insulin (SSI) (33.5%), alprazolam (9.3%), lorazepam (9.3%), quetiapine (5.4%), and diphenhydramine (4.6%). In the fully adjusted model, participants prescribed two PIMs or three or more PIMs had significantly longer lengths of stay and 30-day hospital lengths of stay than those prescribed one PIM (Table 1). Individuals with three or more PIMs also had significantly higher hospital costs than those with one PIM. The number of PIMs prescribed did not significantly affect the odds of readmission within 30 days. Prescribing multiple PIMs in hospitalized elderly adults was associated with longer length of stay and higher hospital costs. The most common PIM was SSI, which the Beers Criteria suggest avoiding because of the risk of hypoglycemia and lack of efficacy in blood glucose control. Despite these recommendations, SSI is still prescribed, although the results may be overestimating its use because the current order entry system does not differentiate between sliding and correction scale. Other PIMs frequently encountered in this study also have risk:benefit profiles to be considered. For example, lorazepam is the preferred drug used at Hartford Hospital to manage alcohol withdrawal. The Beers Criteria acknowledge that some PIMs may be appropriate in certain situations such as advanced severe disease, highlighting the need for thorough clinical judgment for appropriateness. With this in mind, providers are encouraged to use the Beers Criteria to help screen for PIMs and limit their use when possible. Individuals aged 65 and older account for 41% of total hospital costs.7 As the population ages, this is expected to increase, highlighting the importance of identifying interventions to improve efficiency in healthcare spending. Results of this study suggest that PIMs may be one such intervention, although this should be evaluated in future research. Prior studies in hospitalized individuals have found no association between PIM use and mortality, length of stay, decline in activities of daily living, or discharge to a higher level of care.3-6 This study differs most notably in the categorization of number of PIMs rather than evaluating PIM use dichotomously. Along with achieving the estimated sample size, this allowed at which level PIM use negatively affected outcomes to be discerned. Nevertheless, the results should be considered in the context of study limitations. This study reflects prescribing patterns of one hospital in certain medical conditions, so the results may not be broadly applicable. PIM use was defined based on prescribing rather than actual use, and the results may have underestimated the risks associated with PIMs. Future prospective studies would eliminate the potential for residual confounding of variables that it was not possible to adjust for. The authors would like to thank Denis Gannon, PharmD, for his assistance with data collection. Conflict of Interest: The editor in chief has reviewed the conflict of interest checklist provided by the authors and has determined that the authors have no financial or any other kind of personal conflicts with this paper. Author Contributions: All authors contributed to this paper. Sponsor's Role: None.