Author Affiliation: Department of Family Medicine, Case Western Reserve University School of Medicine, Cleveland, Ohio (firstname.lastname@example.org).
To the Editor: The validity of the results of the meta-analysis by Dr Nguyen and colleagues1 regarding an association between androgen deprivation therapy (ADT) and cardiovascular death in patients with prostate cancer is suspect because the 8 studies that met the inclusion criteria may be biased. Androgen deprivation therapy was administered for a time interval that was less than the duration of data collection in 6 of the 8 studies, thereby introducing timing bias. In these 6 studies, ADT was administered for a period ranging from 3 months to 5.1 years, whereas the median duration of data collection in these studies ranged from 7.6 to 13 years. Because the time interval of ADT administration differs from the time interval of data collection in these studies, it is problematic to use them to test whether there is an association between ADT and cardiovascular death.
Blankfield RP. Androgen Deprivation Therapy for Prostate Cancer and Cardiovascular Death. JAMA. 2012;307(12):1252-1253. doi:10.1001/jama.2012.352