In a previous randomized controlled trial, 542 patients (65-95 years) with osteoporosis were randomized to receive an injection of 56.5 mg teriparatide or a placebo injection, once weekly, to determine the effect of this treatment approach on vertebral fracture risk. The purpose of the current analysis was to determine whether the effects remain in a variety of subgroups. Results indicated that significantly favourable effects were observed whether patients were <75 years, 75 years or older, had one or >2 vertebral fractures, had a grade 3 vertebral fracture deformity, had a lumbar bone mineral density less than -2.5 SD, or had bone turnover marker levels and level of renal function over or under the median values.