In the LATITUDE trial, addition of abiraterone acetate plus prednisone to androgen deprivation therapy (ADT) improved overall survival compared with placebos plus ADT in patients with newly diagnosed, high-risk, metastatic castration-naive prostate cancer. Understanding the effects of treatments on patient-reported outcomes (PROs) and health-related quality of life (HRQOL) is important for treatment decisions; therefore we aimed to analyse the effects of ADT plus abiraterone acetate and prednisone versus ADT plus placebos on PROs and HRQOL in patients in the LATITUDE study.