Diabetes mellitus and the risk of fractures at specific sites: a meta-analysis

OBJECTIVE: Diabetes mellitus (DM) is associated with an increased fracture risk; however, the impact of DM and subsequent fracture at different sites and the associations according to patient characteristics remain unknown. DESIGN: Meta-analysis DATA SOURCES: The PubMed, EMBASE and Cochrane Library databases were searched from inception to March 2018. ELIGIBILITY CRITERIA: We included prospective and retrospective cohort studies on the associations of DM and subsequent fracture risk at different sites. DATA EXTRACTION AND SYNTHESIS: Two authors independently extracted data and assessed the study quality. Relative risks (RRs) with 95% CIs were calculated using a random-effects model, and the heterogeneity across the included studies was evaluated using I(2) and Q statistics. RESULTS: Overall, DM was associated with an increased risk of total (RR: 1.32; 95% CI 1.17 to 1.48; p<0.001), hip (RR: 1.77; 95% CI 1.56 to 2.02; p<0.001), upper arm (RR: 1.47; 95% CI 1.02 to 2.10; p=0.037) and ankle fractures (RR: 1.24; 95% CI 1.10 to 1.40; p<0.001), whereas DM had no significant impact on the incidence of distal forearm (RR: 1.02; 95% CI 0.88 to 1.19; p=0.809) and vertebral fractures (RR: 1.56; 95% CI 0.78 to 3.12; p=0.209). RR ratios suggested that compared with patients with type 2 DM (T2DM), patients with type 1 DM (T1DM) had greater risk of total (RR: 1.24; 95% CI 1.08 to 1.41; p=0.002), hip (RR: 3.43; 95% CI 2.27 to 5.17; p<0.001) and ankle fractures (RR: 1.71; 95% CI 1.06 to 2.78; p=0.029). Although no other significant differences were observed between subgroups, the association of DM with upper arm or ankle, vertebrae and total fracture differed according to sex, study design and country, respectively. CONCLUSIONS: Patients with DM had greater risks of total, hip, upper arm and ankle fractures, with T1DM having a more harmful effect than T2DM.