OBJECTIVES: This study aimed at estimating the healthcare costs and identifying potential drivers associated with metastatic castration-resistant prostate cancer (mCRPC).

METHODS: Adult mCRPC patients receiving as first line (1L) treatment abiraterone, enzalutamide or docetaxel associated with LH-RH analogue between 2014-2018 were selected from electronic medical records. Clinical information was deterministically linked with multiple administrative databases to retrieve economic data. Costs were separately summarised for medication, inpatient and outpatient and expressed per-patient per-month (PPPM) for the 1L alone and for the whole study period. For identifying possible cost-drivers, GLM-Gamma models were developed for outpatient and medication costs. Whereas, accounting for the high frequency of zero inpatient costs, Zero-Inflated Gamma models were developed. The study adopted a National Healthcare perspective.

RESULTS: 185 patients were selected for the study. Medication cost was around 1000€/PPPM during the 1L and 1242€/PPPM considering the whole study period. Age, comorbidity and the presence of bone metastases were evaluated as statistical significant predictors of medical costs (p<0.05). A 2% increase in costs was observed for the 1 year age increase; a 25% per unit of Charlson comorbidity index; and a doubling of costs due to the presence of bone metastases. The median inpatient and outpatient costs were 245 and 304€/PPPM respectively during 1L; comparable values were observed when considering the whole study period. The presence of bone and visceral metastases were associated with significantly higher costs (p<0.05) increasing 1L inpatient total costs by 48% and 119%, respectively. The presence of bone metastases increased by 22% (p<0.05) the 1L outpatient costs, respectively. Similar predictors were observed when analyzing the whole study period.

CONCLUSIONS: As expected, the main cost-drivers are associated with the presence of metastasis and chronic conditions. Data show that mCRCP patients do not frequently require acute management, likely because of the increasing chronicity of this disease.