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Potentially severe drug interactions in elderly outpatients: results of an observational study of an administrative prescription database
Author(s) -
Nobili A.,
Pasina L.,
Tettamanti M.,
Lucca U.,
Riva E.,
Marzona I.,
Monesi L.,
Cucchiani R.,
Bortolotti A.,
Fortino I.,
Merlino L.,
Walter Locatelli G.,
Giuliani G.
Publication year - 2009
Publication title -
journal of clinical pharmacy and therapeutics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.622
H-Index - 73
eISSN - 1365-2710
pISSN - 0269-4727
DOI - 10.1111/j.1365-2710.2009.01021.x
Subject(s) - medicine , medical prescription , observational study , odds ratio , pharmacoepidemiology , drug , multivariate analysis , population , odds , defined daily dose , database , pediatrics , emergency medicine , logistic regression , environmental health , pharmacology , computer science
Summary Purpose: To estimate the prevalence of potentially severe drug–drug interactions (DDIs) and their relationship with age, sex and number of prescribed drugs. Methods: We analysed all prescriptions dispensed from 1 January 2003 to 31 December 2003 to individuals aged 65 or more registered under the Local Health Authority of Lecco, a northern Italian province with a population of almost 330 000 persons. Elderly who received at least two co‐administered prescriptions were selected to assess the presence of DDIs. Results: The prevalence of potentially severe DDIs was 16%, and rose with increasing patient’s age and number of drugs prescribed. At multivariate analysis, the adjusted odds ratios rose from 1·07 (95% CI 1·03–1·11) in patients aged 70–74 to 1·52 (95% CI 1·46–1·60) in those aged 85 or older. Elderly taking more than five drugs on a chronic basis had a statistically significant higher risk of sever DDIs than those receiving less than 3 or 3–5 such drugs. Conclusions: The elderly constitutes a population at high risk of DDIs. As physicians still have some difficulty in managing this problem, it is essential to highlight for them, which factors raise the risk of DDIs.