Calcitonin treatment for osteoarthritis and rheumatoid arthritis - a systematic review and meta-analysis of preclinical data.

Purpose: The aim of this study was to investigate the efficacy of calcitonin (CT) in animal models of experimental osteoarthritis (OA) and rheumatoid arthritis (RA), as new stabilized CT formulations are currently being introduced.

Methods: A comprehensive and systemic literature search was conducted in PubMed/MEDLINE and Embase databases to identify articles with original data on CT treatment of preclinical OA and RA. Methodological quality was assessed using the Systematic Review Centre for Laboratory Animal Experimentation's risk of bias tool for animal intervention studies. To provide summary estimates of efficacy, a meta-analysis was conducted for outcomes reported in four or more studies, using a random-effects model. Subgroup analyses were employed to correct for study specifics.

Results: Twenty-six studies were ultimately evaluated and data from 16 studies could be analyzed in the meta-analysis, which included the following outcomes: bone mineral density, bone volume, levels of cross-linked C-telopeptide of type I collagen, histopathological arthritis score, and mechanical allodynia. For all considered outcome parameters, CT-treated groups were significantly superior to control groups (P = 0.002; P = 0.01; P < 0.00001; P < 0.00001; P = 0.04). For most outcomes, effect sizes were significantly greater in OA than in RA (P ≤ 0.025). High in-between study heterogeneity was detected.

Conclusion: There is preclinical evidence for an antioxidant, anti-inflammatory, antinociceptive, cartilage- and bone-protective effect of CT in RA and OA. Given these effects, CT presents a promising agent for the treatment of both diseases, although the potential seems to be greater in OA.