BACKGROUND AND OBJECTIVES:There have been large increases in testosterone prescribing since 2000. The aim of this study was to identify factors associated with testosterone replacement therapy (TRT) initiation in men. METHODS:Data were from the 45 and Up Study, an ongoing cohort study involving 266,942 participants from New South Wales aged ≥45 years. Baseline data (2006−09) were linked to administrative data on government-subsidised prescriptions and medical services. RESULTS:The study included 105,429 men. In two years following baseline, 2.9 per 1000 men (95% confidence interval: 2.6, 3.2) had initiated TRT. Men with self-rated poor health, those treated for osteoporosis; anxiety, depression or high blood cholesterol, and those who lived in major cities or were aged 55–74 years had greater odds of TRT initiation. In the six months before TRT initiation, 41% of men had a hormone test record. DISCUSSION:Discussion The high rate of TRT initiation and low rate of recommended investigations
suggest TRT may have been prescribed outside recommended indications.