A review of data collected from REDUCE (REduction by DUtasteride of prostate Cancer Events) study participants will be performed. Data required for the analysis includes: ethnicity, prostate specific antigen (PSA) levels, prostate volumes, presence of diabetes, concomitant medication use (for statin and ASA), prostate biopsy results at 2 and 4 years, body mass index (BMI), digital rectal exam (DRE) results, family history of Prostate Cancer and benign prostatic hyperplasia (BPH) outcomes: urinary retention, international prostate symptom score (IPSS), urinary tract infections (UTI)s.
The association of drug interactions with prostate cancer will be explored by using a multivariate logistic regression model including all possible interaction terms between dutasteride, ASA and statins (i.e. statin+ASA+dutasteride, statin+ASA, dutasteride+statin, dutasteride+ASA). Any interaction term found to be insignificant ( i.e. p\>0.05) will be removed from the model. If a statistically significant interaction term is identified, the study cohort will be stratified by drug use, and the relative risk (RR)of prostate cancer among the different drug users will be reported. To control for potential confounders, a multivariate regression model will be constructed adjusting for age, family history of prostate cancer, DRE results and BMI.
