Pacifici 1988.

Methods	Randomized controlled trial. Parallel group Study length: 2 years Secondary prevention Blinding: open study, blinded radiologists Withdrawals: Etidronate: 14/30 (46.7%) Control: 12/27 (44.4%) Total: 26/57 (46%)
Participants	Source: Women who came to one USA hospital for osteoporosis screening. Inclusion Criteria: At least 1 non traumatic vertebral fracture and/or evidence of spinal demineralization by QCT. Exclusion Criteria: Any condition influencing calcium metabolism or contraindicating study medications. Treatment N = 30 Control N = 27 Age: 61 (7.8); YSM: 13.8 (9.5) Calcium: 875 mg/day (406) QCT: 79.1 mg/cm3 (26.3) Fractures: 100% had fractures and/or evidence of demineralization on QCT
Interventions	Etidronate 400mg/day with 7.5g K phosphate/cycle vs control (56 days) (1g calcium /day)
Outcomes	Vertebral Fractures: Caliper measurement of vertical height for anterior, central and posterior regions of each vertebra in lateral spine films. Compression fracture was defined by a 15% greater loss of posterior height compared with nearest intact vertebrae. In vertebrae with normal posterior height, wedging and biconcave fractures were defined by a loss of anterior and central height > 20% of posterior height of same vertebrae. Number of new fractures was calculated every 12 months.
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Allocation concealment?	Unclear risk	B ‐ Unclear