Numerous characteristics of a medication regimen can weaken patient adherence to drug therapy and thus impair clinical outcomes of drug therapy.Objective
The aim of the study was to investigate the prevalence of medication regimen characteristics that are known to reduce patient adherence to drug therapy. Furthermore, we assessed to what extent complex medication regimens can possibly be simplified through different strategies.Methods
We retrospectively evaluated the medication regimens of 500 consecutive patients discharged from the University Hospital of Heidelberg, Germany, in whom the dosages of all drugs were specified. The medication regimens were extracted from the discharge letters issued between 1 January 2007 and 29 December 2007. Each medication regimen was checked for the presence of seven regimen characteristics that are known to reduce patient adherence, and theoretical viable strategies to avoid four of the respective characteristics were identified. The extent of possible simplification through the identified strategies was evaluated for the overall study population and the subgroup of elderly patients (≥65 years) with polypharmacy (≥5 drugs).Results
On average, every medication regimen in the overall study population had 2.9 ± 1.7 (standard deviation) characteristics (range 0-7) known to impair patient adherence. In contrast, the medication regimens of elderly patients with polypharmacy contained 3.7 ± 1.6 characteristics (range 0-7) known to impair patient adherence. The most prevalent complexity characteristics in the overall study population were prescription of ≥1 drug with multiple doses per day (441 patients), ≥3 drugs with different dosing intervals (349 patients), tablet splitting (223 patients), followed by ≥12 daily drug administrations (190 patients). Almost half of the prescribed tablet splitting could be prevented. Moreover, 17.9 % of the multi-dose prescriptions could be switched to once-daily dosing, and thus reduced the number of drugs with different dosing intervals and the number of daily drug administrations. The combined intervention reduced the total number of potentially preventable complexity characteristics by 18.3 % (from 2283 to 1865 characteristics) without reducing prescription quality.Conclusion
Almost one-fifth of all regimen complexity characteristics relevant for patient adherence were avoidable by simple modifications of the medication scheme, stressing the need for targeted interventions.