Gallagher 2001.

Methods	Sites Testing Osteoporosis Prevention / Intervention Treatment (STOP IT). Randomised, double‐blind, placebo‐controlled trial using 2 x 2 factorial design.
Participants	Country: United States. Number of participants randomised: 489 healthy elderly women 65 to 77 (mean 71.5) years of age. Inclusion criteria: healthy elderly women 65 to 77 years of age and femoral neck density within the normal range for their age. Exclusion criteria: severe chronic illness, primary hyperparathyroidism or active renal stone disease, and were on certain medications, such as bisphosphonates, anticonvulsants, oestrogen, fluoride, or thiazide diuretics in the previous 6 months.
Interventions	Participants were randomly assigned to receive: Intervention group 1: calcitriol (0.5 μg) daily (n = 123); Intervention group 2: conjugated oestrogens (Premarin) 0.625 mg/daily plus medroxyprogesterone acetate (Provera) 2.5 mg daily (n = 121); Intervention group 3: calcitriol (0.5 μg) plus conjugated oestrogens daily; (Premarin) 0.625 mg/daily plus medroxyprogesterone acetate (Provera) 2.5 mg daily (n = 122); Intervention group 4 (Control group): matched placebo daily (n = 123); for a three‐year period.
Outcomes	The primary outcome measure was the change in bone mineral density of the femoral neck and spine. Secondary outcome measure was incidence of nonvertebral fractures.
Stated aim of study	"To examine the effect of oestrogen and 1,25‐dihydroxyvitamin D therapy given individually or in combination on bone loss in elderly women."
Notes	"Compliance to trial medication was evaluated by pill counts. At 36 months, treatment group differences in adherence to assigned therapy were evident, with 78% of those assigned to placebo, 70% of those assigned to calcitriol, 65% of those assigned to HRT/ERT and 62% of those assigned to HRT/ERT calcitriol still adherent to their assigned medication. Among those still on medication the compliance for the groups calculated at six months and compared with 36 months, respectively, was: conjugated estrogens, 86% and 92%; medroxyprogesterone acetate, 91% and 94%; calcitriol, 87% and 93%; placebos, 94% and 92%." The active trial drug and placebo were supplied by Wyeth‐Ayerst Laboratories, Inc Pharm, Hoffman‐LaRoche Inc and Pharmacia & Upjohn, Inc. Additional information on mortality and risk of bias domains was received through personal communication with Dr John Gallagher (09.02.2009; 11.03.2010).
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Sequence generation was achieved using computer random number generation.
Allocation concealment (selection bias)	Low risk	Allocation was controlled by a central and independent randomisation unit so that intervention allocations could not have been foreseen in advance of, or during, enrolment. An independent statistical group performed the blinding and randomisation.
Blinding (performance bias and detection bias) All outcomes	Low risk	The trial was described as blinded, the parties that were blinded, and the method of blinding was described, so that knowledge of allocation was adequately prevented during the trial.
Incomplete outcome data (attrition bias) All outcomes	Low risk	The numbers and reasons for dropouts and withdrawals in all intervention groups were described.
Selective reporting (reporting bias)	Low risk	Pre‐defined, or clinically relevant and reasonably expected outcomes are reported on.
Industry bias	Unclear risk	The active trial drug and placebo were supplied by Wyeth‐Ayerst Laboratories, Inc Pharm, Hoffman‐LaRoche Inc and Pharmacia & Upjohn, Inc.
Other bias	Low risk	The trial appears to be free of other components that could put it at risk of bias.