Potentially severe drug interactions in elderly outpatients: results of an observational study of an administrative prescription database

Abstract

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 1AE07 (95% CI 1AE03-1AE11) in patients aged 70-74 to 1AE52 (95% CI 1AE46-1AE60) 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.

Potential Drug-Drug Interactions in Psychiatric Ward of a Tertiary Care Hospital: Prevalence, Levels and Association with Risk Factors

“…Our findings regarding strong association of pDDIs with long hospital stay and taking increased number of drugs; and insignificant association with gender are consistent with other studies [5,6,8,9]. According to our findings, there was no significant relationship between old age and pDDIs that is inconsistent with other studies [5,[7][8][9][10]. The possible reason for this inconsistency might be the small proportion of old age patients in our study population, i.e., 41(10 %) patients were of age 46 -60 years and only 7(2 %) patients were older than 60 years ( Table 1).…”

“…Prevalence of potential DDIs (pDDIs) in hospital settings has been estimated in some recent studies to be in the range of 27.8 to 51.4 % [2][3][4]. Old age, taking increased number of medications, long hospital stay, gender and comorbid conditions have been reported as common risk factors for DDIs [5][6][7][8][9][10][11].…”

Prevalence and predictors of potential drug-drug interactions

“…The present results indicated that the sex was not associated with the occurence of potential DDIs. These results were expected, given that there was no statistical significant difference between the sex and the number of clinical significant potential DDIs [27,46]. While, Cruciol-Souza et al identified female sex as a predictor of potential DDIs in hospitalized Brazilian patients [25].…”

“…Additionally, the frequency study of potential DDIs at geriatric outpatient in 6 European countries showed that there were differences in frequency, as well as in the type of potential DDIs [23]. By study of predictors to DDIs was also observed variability, those which are patient characteristics as well as those which are therapy characteristics [20][21][22][24][25][26][27][28][29][30][31][32]. Differences in healthcare settings, registered and reimbursed pharmaceutical specialities can contribute to different utilization patterns of prescription drugs.…”

A study of potential drug-drug interactions among critically ill patients at a tertiary care hospital

“…[5][6][7]9,12,[15][16][17] Hence, we can say that pDDI are more common in elderly probably due to age related physiological, pharmacokinetic and pharmacodynamic changes.…”