Sampled participants

Male patients aged ≥20 years with newly diagnosed GSD (ICD-9-CM codes 574.0, 574.1, 574.2, 574.6, 574.7, 574.8, 574.9) from 1998–2011 were identified using the LHID2000. The date of GSD diagnosis was defined as the index date. Patients with a history of prostate cancer (ICD-9-CM code 185) were excluded. The non-GSD cohort consisted of patients randomly selected from the LHID2000 without a GSD history. For each GSD case, 4 men without GSD were randomly selected as the control cohort through frequency matching according to sex, age (every 5-y span), and the index date year. The same exclusion criteria were also applied to non-GSD controls. Figure ​Figure11 provided a flow chart to summarize the study design and the subjects' selection in this study.