gms | German Medical Science

Background: Polypharmacy is associated with increased risks of drug interaction and adverse drug reactions [1]. A masked multi-medication can arise if self-medicated preparations are consumed additionally to prescribed medication. Often, this masked multi-medication is unknown by the attending physicians. In Germany data on drug consumption including self-medication are only available from the national health surveys of the Robert Koch Institute.

The aims of this study are to describe the prevalence of polypharmacy (total and prescribed) and to analyze trends in polypharmacy (total and prescribed) between the GNHIES98 and the (DEGS1, 2008–2011)

Materials and Methods: Information on medication use among women and men aged 18-79 years is available for a total of N=7099 from GNHIES98 and N=7091 from DEGS1. The currant use of medication (during 7 days preceding the interview) was recorded via a standardized Computer Assisted Interview (CAPI) [2]. The coding of the recorded preparations was based on the German version of the Anatomical-Therapeutical-Chemical (ATC) classification [3]. Total polypharmacy is defined as the use of 5 or more preparations during the preceding 7 days. Prescribed polypharmacy is defined as the use of 5 or more preparations prescribed by a physician.

Results: At the time of DEGS1 85.4% of women and 63.8% of men use at least one medication or nutritional supplement. The prevalence of polypharmacy amounts to 22.8% in women and 13.8% in men. Polypharmacy prescribed by physician’s amounts to 13.6% in women and 9.9% in men. The prevalence of total- and of prescribed polypharmacy rises with older age. While women of all age-groups show significantly higher prevalence rates for the use of total polypharmacy, prescribed polypharmacy is only in women aged 40-49 years significantly higher. Trend analyses between GNHIES98 and DEGS1 reveal a significant rise of total polypharmacy for both sexes among the age group 60+ years (women 38.4% vs. 46.6%, men 29.8% vs. 37.3%). Also, for polypharmacy prescribed by physicians a rise can be observed but this is only significant in men. In multivariate analyses the probability of total- and prescribed polypharmacy is significantly increased even after adjustment for age, sex, health status and last visit of a doctor.

Conclusion: Data of the national health surveys supply valid information on real exposition to medication among outpatients and on the extent of polypharmacy. Additionally, repeated representative surveys allow estimation of trends in polypharmacy. The assessment of polypharmacy with the inclusion of self-medication has a particularly high relevance concerning the safety of drug use.