Potentially inappropriate medication in elderly primary care patients. A retrospective, longitudinal analysis

Elderly people are often burdened by several diseases. This accounts for a higher medication intake and increases the risk of adverse drug events. To minimize this risk, several lists (Beers, PRISCUS) have been published of drugs that elderly patients should not take. We present a longitudinal analysis of the use of potentially inappropriate medication (PIM) over a period 4.5 years in a cohort of patients aged 75 years or more. Data were collected from the prospective, multicenter, observational study German Study on Ageing, Cognition and Dementia in Primary Care Patients (AgeCoDe), initially enrolling 3,327 patients. We investigated the prevalence of PIM by checking medications during visits to patients' homes. Furthermore, we analyzed the use of individual PIM agents over time. At baseline, we found a PIM prevalence of 29 % according to the PRISCUS list, which decreased to 25.0 % 4.5 years later (chi(2): 7.87, p = 0.004). The Beers list yielded a prevalence of 21 % at baseline, decreasing after 4.5 years to 17.1 % (chi(2): 10.77, p = 0.000). A time-dependent multilevel model confirmed these results. Older age, depression, and the use of numerous prescribed agents are independent risk factors for using a PRISCUS-PIM. Our results seem to support a trend toward a more rational drug therapy because fewer patients were prescribed PIM. Thus, for the individual patient, the risk of adverse effects and side effects is reduced as are the costs of these effects.