@article { ISI:000345076200013,
	title = {Association between beta-interferon exposure and hospital events in multiple sclerosis},
	journal = {Pharmacoepidemiology and Drug Safety},
	volume = {23},
	number = {11},
	year = {2014},
	pages = {1213-1222},
	publisher = {WILEY-BLACKWELL},
	address = {111 RIVER ST, HOBOKEN 07030-5774, NJ USA},
	abstract = {<p>Purpose A systematic evaluation of hospital events can be an important surrogate measure for drug effectiveness or adverse effects. The purpose of this study was to examine the association between beta-interferon use and hospital events in a large cohort of patients with multiple sclerosis (MS). MethodsRetrospective cohort study comparing beta-interferon exposed and unexposed patients using clinical data from the British Columbia MS (BCMS) database linked with health administrative databases, 1996-2008. For each patient, the primary outcome was the number of hospital events in each month, analyzed by quasi Poisson regression. Beta-interferon exposure was examined two ways: current and cumulative exposure. Secondary outcomes included whether a hospital event occurred in each month for each specific primary diagnoses, grouped by International Classification of Diseases categories. ResultsCurrent exposure to beta-interferon was not associated with an altered rate of hospital events (adjusted incident rate ratio 1.018; 95\% CI 0.803-1.290). Similarly, there was no association with cumulative exposure. Cumulative beta-interferon exposure was associated with a lower odds of respiratory disease-related hospital events compared to those never exposed to beta-interferon. ConclusionsExposure to beta-interferon for MS was not associated with a change in overall hospital event rates. Preliminary evidence suggests that the beta-interferons may have a protective effect against respiratory diseases requiring hospitalization in MS patients. Copyright (c) 2014 John Wiley \&amp; Sons, Ltd.</p>
},
	keywords = {beta-interferon, hospitalization, multiple sclerosis, pharmacoepidemiology},
	doi = {10.1002/pds.3667},
	author = {Evans, C and Zhu, F and Kingwell, E and Shirani, A and van der Kop, ML and Petkau, J and Gustafson, P and Zhao, Y and Traboulsee, A and Oger, Joel and Tremlett, Helen}
}
