Drug adherence and drug-related problems in pharmacotherapy for lower urinary tract symptoms related to benign prostatic hyperplasia

Abstract

Lower urinary tract symptoms (LUTS) associated with benign prostatic hyperplasia (BPH) is one of the most common urinary disorders in elderly men. In recent years, pharmacotherapy of BPH has increased the efficacy, including combination treatment mostly with two drug classes, namely, 5-α-reductase inhibitors and α-1-adrenolytics (alpha blockers) with a different pharmacological activity. Although pharmacological treatment of BPH is a success story in urology, daily practice suggests that several medical needs remain unmet. We aimed to evaluate drug adherence in patients receiving pharmacological therapy to treat LUTS/BPH, and to analyze drug adherence among monotherapy and combination therapy. The sample population consisted of 758 men aged > 40 years who had been prescribed medications for LUTS/BPH during the index period between June 2015 and August 2016. Only alpha blockers and 5-α-reductase inhibitors (5ARIs) were considered in the analysis. Among ABs there were doxazosin, tamsulosin, alfuzosin, terazosin and among 5-α-reductase inhibitors it was only finasteride. Drug adherence was assessed in patients who were treated for a minimum of 6 months. Two levels of exposure were evaluated, follow-ups: ≥ 6 months, and ≥ 12 months. In patients who were treated for at least 6 months, the drug adherence rate was 32% and the 12-month drug adherence rate was 23%. We observed an inverse relationship between drug adherence rates and the duration of treatment - longer the duration of pharmacological therapy, lower was the drug adherence rate noted. Our study shows a low rate of overall drug adherence in patients diagnosed with BPH. It was observed that a low adherence rate is closely related to drug-related problems (DRP). Furthermore, this is a correlation between the degree of LUTS/BPH and adherence rate - the higher degree of LUTS/BPH, the higher adherence rate. Further studies are warranted focusing on assessing adherence to pharmacological therapy.