A Cochrane review included 30 studies with a total of 3 682 subjects. For the proportion of patients with pain relief (eight studies) pooled data showed benefits for the treatment group, with an NNT at 4 weeks of 11 (95% CI 6 to 36) and at 12 weeks of 7 (95% CI 5 to 12). In terms of adverse drug reactions, the NNH was 16 (95% CI 12 to 27) for discontinuation of therapy. Nausea and vomiting were reported in 24 studies with a non-significant trend for greater risk in the treatment group. One study showed a small improvement in quality of life for the treatment group at 4 weeks.
Comment: The quality of evidence is downgraded by sparse data. The small number of studies in each subgroup with relevant data prevented exploring the most effective bisphosphonates and their relative effectiveness for different primary neoplasms. When the three most stringent inclusion criteria are applied (blinded control, pain as an eligibility criteria, and patient reported pain), only two studies can be included, precluding meaningful pooling of the results, and the amount of pain relief achieved from bisphosphonates appears to be small.