Development of a Comorbidity Score Based on Institutionalization:Comparative Performance with a Comorbidity Score Modeled on Mortality
|Sarah-Gabrielle Béland1,2, Cara Tannenbaum1,3, Thierry Ducruet1,2, Michel Préville4 and Yola Moride1,2*|
|1Faculty of Pharmacy, Université de Montréal, Montreal, Quebec, Canada|
|2Pharmacoepidemiology Unit, Research Centre, University of Montreal Hospital Centre (CRCHUM), Montreal, Quebec, Canada|
|3Research Center, Institut Universitaire de Gériatrie de Montréal, Montreal, Quebec, Canada|
|4Charles LeMoyne Hospital Research Center, Université de Sherbrooke, Longueuil, Quebec, Canada|
|Corresponding Author :||Yola Moride
Faculty of Pharmacy
Université de Montréal
CP 6128, Succursale Centre-Ville
Montreal Qc H3C 3J7, Canada
E-mail: [email protected]
|Received October 24, 2012; Accepted November 23, 2012; Published November 25, 2012|
|Citation: Béland SG, Tannenbaum C, Ducruet T, Préville M, Moride Y (2013) Development of a Comorbidity Score Based on Institutionalization: Comparative Performance with a Comorbidity Score Modeled on Mortality. J Gerontol Geriat Res 2:116. doi:10.4172/2167-7182.1000116|
|Copyright: © 2013 Béland SG, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.|
Background: Comorbidity scores based on the prediction of 1-year mortality risk are used in pharmacoepidemiologic and pharmacoeconomic research to control for unmeasured confounding. However, admission to a long-term care institution may be a more salient and discriminant outcome on which to base comorbidity scores.
Objective: To develop a prescription claims-based comorbidity score to predict institutionalization in the community-dwelling elderly population, and to compare its performance against existing mortality comorbidity scores.
Methods: A geriatric institutionalization comorbidity index was derived from data of a retrospective cohort of 61,172 community-dwelling older adults identified through the Quebec claims databases (2000-2009). Predictors of institutionalization were identified through clinical expertise and by nested case-control analysis. The Framingham Heart Study method was used to develop the score. The performance of the score was assessed through the c-statistic in a separate validation cohort of 26,216 persons and compared with the performance of a mortality score, the Geriatric Comorbidity Index. The robustness was assessed in a cohort of elderly individuals with dementia.
Results: Drugs associated with an increased risk of institutionalization were: antipsychotics, antidepressants, hypoglycaemic agents, statins, benzodiazepines and antihypertensives. The mean score assigned to cases was significantly different from that of controls. The c-statistic for the Institutionalization Comorbidity Index was 0.79 (95% CI: 0.77-0.83) compared to 0.75 (95% CI: 0.73-0.78) for the mortality index. The score was robust when in the dementia cohort Comorbidity Index was 0.81 95% CI: 0.78-0.84).
Conclusion: A score that predicts institutionalization in the community-dwelling elderly population offers improvement over existing comorbidity scores. It may therefore be used in research conducted in this population, especially for drug effectiveness and health economic studies which often involve institutionalization as the outcome