Risk of malignancy in patients with giant cell arteritis and polymyalgia rheumatica: a systematic review and meta-analysis

Objective: To investigate the association between giant cell arteritis (GCA)/polymyalgia rheumatica (PMR) and malignancy risk.

Methods: We conducted a systematic review and meta-analysis of cohort studies that reported relative risk, hazard ratio, or standardized incidence ratio (SIRs) with 95% confidence comparing malignancy risk in patients with GCA/PMR versus non-GCA/PMR participants. Pooled risk ratios and 95% confidence intervals were calculated using a random-effect, generic inverse variance method.

Result: A total of six studies were identified and included in our data analysis. The pooled risk ratio of malignancy in patients with GCA/PMR was 1.14 (95% CI: 1.05-1.22). The risk was higher in the first 6-12 months after diagnosis with the pooled risk ratio of 2.16 (95% CI: 1.85-2.53). However, when we performed a sensitivity analysis that excluded one study with a potential selection bias, the pooled risk ratio decreased and did not achieve statistical significance.

Conclusion: Our study demonstrated a low but statistically significant increased malignancy risk among patients with GCA/PMR. However, when we excluded one study with potential selection bias, the new pooled risk ratio did not achieve statistical significance.