Health care costs for prostate cancer patients receiving androgen deprivation therapy: treatment and adverse events

Background Serious adverse events have been associated with androgen deprivation therapy (ADT) for prostate cancer (PCA), but few studies address the costs of those events. Methods All PCA patients (ICD-9-CM 185) in Ontario who started 90 days or more of ADT or had orchiectomy at the age of 66 or older during 1995-2005 (n = 26,809) were identified using the Ontario Cancer Registry and drug and hospital data. Diagnosis dates of adverse events-myocardial infarction, acute coronary syndrome, congestive heart failure, stroke, deep vein thrombosis or pulmonary embolism, any diabetes, and fracture or osteoporosis-before and after ADT initiation were determined from administrative data. We excluded patients with the same diagnosis before and after ADT, and we allocated each patient's time from ADT initiation to death or December 31, 2007, into health states: ADT (no adverse event), ADT-AE (specified single adverse event), Multiple (>1 event), and Final (<= 180 days before death). We used methods for Canadian health administrative data to estimate annual total health care costs during each state, and we examined monthly trends. Results Approximately 50% of 21,811 patients with no pre-ADT adverse event developed 1 or more events after ADT. The costliest adverse event state was stroke ($26,432/year). Multiple was the most frequent (n = 2,336) and the second most costly health state ($24,374/year). Costs were highest in the first month after diagnosis (from $1,714 for diabetes to $14,068 for myocardial infarction). Costs declined within 18 months, ranging from $784 per 30 days (diabetes) to $1,852 per 30 days ( stroke). Adverse events increased the costs of ADT by 100% to 265%. Conclusions The economic burden of adverse events is relevant to programs and policies from clinic to government, and that burden merits consideration in the risks and benefits of ADT.