Tilyard 1992.

Study characteristics
Methods	Multi‐centre randomised single‐blind comparison of calcitriol and calcium supplementation. No placebo, and each participating physician (123) had own separate randomisation code. Participant compliance not checked 515 of 622 completed at 1 year, 476 at 2 years, 432 at 3 years
Participants	Community‐based study, New Zealand 622 fully ambulatory post‐menopausal women aged 50 to 79 years (mean 63.7 years) with no evidence of disease or drug known to cause osteoporosis, from a population referred with fracture or other manifestation of effects of osteoporosis Inclusion criteria: presence of 1 or more non‐traumatic vertebral compression fracture seen on a lateral spinal radiograph Exclusion criteria: not specifically described
Interventions	1. Calcitriol 0.5 μg daily in 2 doses by mouth Randomised 314, completed 1 years 262, 2 years 236, 3 years 213 2. Elemental calcium 1 g daily (5.2 g calcium gluconate twice daily). Randomised 308, completed 1 years 253, 2 years 240, 3 years 219 Patients instructed not to take any other calcium supplement, but otherwise diet, and exercise programmes were unsupervised Duration of treatment 3 years
Outcomes	Measured at 1, 2, and 3 years 1. Number of women with new vertebral fractures 2. Number of fractures of the appendicular skeleton by the end of 3 years of treatment 3. Episodes of hypercalcaemia 4. Renal calculi 5. Number of persons dying 6. Gastro‐intestinal symptoms
Notes	Interim reports published in 1990 and 1991
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	States "randomization codes", no other information provided
Allocation concealment (selection bias)	Unclear risk	No details provided