Retrospective SHI (Statutory Health Insurances) real-world study on initial GnRH antagonist and agonist therapy for advanced prostate cancer: Prescription patterns and hospital costs in Germany

Abstract

Introduction: Androgen deprivation therapy (ADT) plays a pivotal role in the treatment of advanced or metastasised prostate cancer (PCa). The aim of this health services research was to compare real-world data on the initial use of different GnRH agonists and antagonists (GnRHa) with regard to prescription patterns, hospitalisation rates and costs. Material and methods: Anonymised claims data from>70 German health insurance funds between 2010 and 2015 (n=4205227) were analysed (1 year pre-observation period, 1 index quarter with initial GnRHa prescription,≥2 years of follow-up (FU)). Results: The study population included 2382 PCa patients (mean age 75 years). Leuprolide (Leu) was prescribed most frequently (56.6%). At initial GnRHa administration, 70% of patients neither had lymph node nor distant metastases. Around 11.2% of all patients stopped GnRHa treatment after the first prescription, 17.6% switched their initial therapy to another substance after a mean of 457 days (median: 399 days); in the hybrid (hyb) group 100 days earlier on average than in the agonist group (p=0.016). The prevalence ranking of the most common comorbidities was consistent over time: hypertension, hyperlipidaemia, cardiovascular disease (CVD) and diabetes. The prevalence of hypertension increased significantly in the agonist group (16.4%) compared with the antagonist (6.9%, p=0.022) and hyb group (11.6%, p=0.006). With regard to CVD, there were no significant differences in the relative growth rate between the 3 combined therapy classes. In total, 23.9% of all patients died within the 3-year FU. The mortality rate was lowest for triptorelin (Trp, 22.1%) and highest for goserelin (Gos, 29.4%, n.s.). In the index quarter, 26.4% of patients had at least one inpatient hospitalisation [min-max: Trp 22.4%; Gos 30.3%], with an average length of hospital stay/patient of 3 days [Trp 2.4; Gos 4.5]. The annual hospitalisation rate was between 36.2 and 40.7%, the average length of hospital stay in the entire FU was between 17.6 (Trp) and 20.8 days (hyb). The average hospital costs in the index quarter were approx. EUR 1200 [Trp 988; Gos 1803] and per FU year approx. EUR 3000. In the Trp cohort, total costs (index quarter+3 years) were more than EUR 1000 below the average costs of EUR 9476 [Trp 8116; Leu 9779; n.s.]. Conclusion: This comparative retrospective analysis provides real-world information on initial GnRHa treatment for advanced prostate cancer, revealing differences in treatment patterns, hospitalisation rates and hospital costs in Germany.