Associations of hyperuricemia, gout, and UA-lowering therapy with the risk of fractures: A meta-analysis of observational studies.

Objective: A systematic review and meta-analysis were conducted to investigate the associations of hyperuricemia, gout, and uric acid (UA)-lowering therapy with the risk of fractures.

Methods: Electronic searches on PubMed, the Cochrane Library, and Embase were conducted from inception to January 2, 2019. Observational studies assessing the effects of hyperuricemia, gout, and UA-lowering therapy on fractures were included in the meta-analysis. Summary risk estimates with 95% confidence intervals (CI) were calculated by a random-effects model.

Results: A total of 14 eligible studies with 909 803 participants and 64 047 incident fractures were included. The results suggested that hyperuricemia and gout are not associated with any type of fracture (relative risk [RR], 0.98, 95% CI 0.85-1.11; P = 0.71) or osteoporotic fractures (RR, 1.02, 95% CI 0.90-1.14; P = 0.79). Further analysis indicated that hyperuricemia is associated with a lower risk of fractures (RR, 0.80, 95% CI 0.66-0.96; P = 0.02) but not with osteoporotic fractures (RR, 0.84, 95% CI 0.68-1.03; P = 0.10). However, gout is associated with an increased risk of fractures (RR, 1.17, 95% CI 1.04-1.31; P = 0.007) as well as osteoporotic fractures (RR, 1.13, 95% CI 1.00-1.26; P = 0.045). Furthermore, no significant association of UA-lowering therapy with the risk of fractures was found compared with the placebo (RR, 0.88, 95% CI 0.76-1.03; P = 0.11). Evidence supporting a non-linear association between serum UA levels and fractures was found (P < 0.001 for non-linearity), which revealed a U-shaped curve.

Conclusion: Our meta-analysis revealed that hyperuricemia was associated with lower risk for any type fracture but not associated with osteoporotic fractures; however, gout was associated with an increased risk of any type fracture as well as osteoporotic fractures. Notably, a U-shaped relationship may exist between the serum UA level and fractures. The associations observed in our study may be due to reasons other than causality.