OBJECTIVES: To review the evidence on the efficacy and safety of treatment for osteoporosis in people with beta-thalassaemia.

SEARCH METHODS: We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group's Haemoglobinopathies Trials Register, which includes references identified from comprehensive electronic database searches and handsearches of relevant journals and abstract books of conference proceedings. We also searched online trial registries. Date of most recent search: 4 August 2022.

SELECTION CRITERIA: Randomized controlled trials (RCTs) in people with beta-thalassaemia with: a BMD Z score below -2 standard deviations (SDs) for children aged under 15 years, adult males (aged 15 to 50 years) and premenopausal females aged over 15 years; or a BMD T score below -2.5 SDs for postmenopausal females and males aged over 50 years.

DATA COLLECTION AND ANALYSIS: Two review authors assessed the eligibility and risk of bias of the included RCTs, and extracted and analysed data. We assessed the certainty of the evidence using GRADE.

MAIN RESULTS: We included six RCTs (298 participants). Active interventions included bisphosphonates (3 trials, 169 participants), zinc supplementation (1 trial, 42 participants), denosumab (1 trial, 63 participants), and strontium ranelate (1 trial, 24 participants). The certainty of the evidence ranged from moderate to very low and was downgraded mainly due to concerns surrounding imprecision (low participant numbers), but also risk of bias issues related to randomization, allocation concealment, and blinding. Bisphosphonates versus placebo or no treatment Two RCTs compared bisphosphonates to placebo or no treatment. After two years, one trial (25 participants) found that alendronate and clodronate may increase BMD Z score compared to placebo at the femoral neck (mean difference (MD) 0.40, 95% confidence interval (CI) 0.22 to 0.58) and the lumbar spine (MD 0.14, 95% CI 0.05 to 0.23). One trial (118 participants) reported that neridronate compared to no treatment may increase BMD at the lumbar spine and total hip at six and 12 months; for the femoral neck, the study found increased BMD in the neridronate group at 12 months only. All results were of very low-certainty. There were no major adverse effects of treatment. Participants in the neridronate group reported less back pain; we considered this representative of improved quality of life (QoL), though the certainty of the evidence was very low. One participant in the neridronate trial (116 participants) sustained multiple fractures as a result of a traffic accident. No trials reported BMD at the wrist or mobility. Different doses of bisphosphonate compared One 12-month trial (26 participants) assessed different doses of pamidronate (60 mg versus 30 mg) and found a difference in BMD Z score favouring the 60 mg dose at the lumbar spine (MD 0.43, 95% CI 0.10 to 0.76) and forearm (MD 0.87, 95% CI 0.23 to 1.51), but no difference at the femoral neck (very low-certainty evidence). This trial did not report fracture incidence, mobility, QoL, or adverse effects of treatment. Zinc versus placebo One trial (42 participants) showed zinc supplementation probably increased BMD Z score compared to placebo at the lumbar spine after 12 months (MD 0.15, 95% CI 0.10 to 0.20; 37 participants) and 18 months (MD 0.34, 95% CI 0.28 to 0.40; 32 participants); the same was true for BMD at the hip after 12 months (MD 0.15, 95% CI 0.11 to 0.19; 37 participants) and 18 months (MD 0.26, 95% CI 0.21 to 0.31; 32 participants). The evidence for these results was of moderate certainty. The trial did not report BMD at the wrist, fracture incidence, mobility, QoL, or adverse effects of treatment. Denosumab versus placebo Based on one trial (63 participants), we are unsure about the effect of denosumab on BMD Z score at the lumbar spine, femoral neck, and wrist joint after 12 months compared to placebo (low-certainty evidence). This trial did not report fracture incidence, mobility, QoL, or adverse effects of treatment, but the investigators reported a reduction in bone pain measured on a visual analogue scale in the denosumab group after 12 months of treatment compared to placebo (MD -2.40 cm, 95% CI -3.80 to -1.00). Strontium ranelate One trial (24 participants) only narratively reported an increase in BMD Z score at the lumbar spine in the intervention group and no corresponding change in the control group (very low-certainty evidence). This trial also found a reduction in back pain measured on a visual analogue scale after 24 months in the strontium ranelate group compared to the placebo group (MD -0.70 cm (95% CI -1.30 to -0.10); we considered this measure representative of improved quality of life.