Risk of new-onset diabetes mellitus and worsening glycaemic variables for established diabetes in men undergoing androgen-deprivation therapy for prostate cancer

OBJECTIVE: To investigate the incidence of new-onset diabetes mellitus (NODM) and of worsening glycaemic control in established DM after starting androgen-deprivation therapy (ADT) for prostate cancer, as ADT is associated with altered body composition, potentially influencing insulin sensitivity. PATIENTS AND METHODS: We retrospectively reviewed patients receiving ADT for prostate cancer at our institution between January 1989 and July 2005; those with incomplete information and those receiving only neoadjuvant ADT were excluded. Variables examined included age, race, body mass index (BMI), pretreatment prostate-specific antigen, Gleason sum, clinical stage, ADT type (medical vs surgical) and schedule (continuous vs intermittent), presence of pre-existing DM, serum glucose and glycosylated haemoglobin (HbA1c) levels before and after ADT, and receipt of vitamin D or bisphosphonate supplementation. Data were analysed statistically and P < 0.05 considered to indicate significance. RESULTS: In all, 396 patients (median age 73.2 years; median BMI of 26.7 kg/m² at ADT initiation) were analysed. Of these, 59.1% were African-American and 40.9% were Caucasian/other. At a median follow-up of 60.1 months, 36 (11.3%) patients developed NODM. In 77 patients with pre-existing DM, there was an increase of ≥10% in serum HbA1c or fasting glucose levels in 15 (19.5%) and 22 (28.6%), respectively. On multivariate analysis, a BMI of ≥30 kg/m² was associated with an increased risk of developing NODM (odds ratio 4.65, P = 0.031). Receipt of vitamin D had a protective effect (odds ratio 5.75, P = 0.017). CONCLUSIONS: Patients receiving ADT for prostate cancer with or with no history of DM should have routine surveillance of glycaemic control, particularly when their BMI is ≥ 30 kg/m², with appropriate preventive and treatment measures.