Alkaline phosphatase is useful for predicting giant cell arteritis complications in patients with polymyalgia rheumatica

Objectives: This study determined whether alkaline phosphatase (ALP) can be used to distinguish giant cell arteritis (GCA) complications in patients with polymyalgia rheumatica (PMR). Methods: This retrospective study included patients diagnosed with PMR between January 2014 and October 2023 at our hospital. The predictive accuracy of biomarkers for diagnosing GCA was evaluated. Logistic regression was performed to identify factors predicting GCA complications. Results: In total, 128 participants were included in this study and divided into two groups: isolated PMR (n = 111) and PMR with GCA (n = 17). The median ALP level of PMR with GCA group was significantly higher than that of the isolated PMR group (242.0 [interquartile range, 221.0-595.0] vs. 187.0 [interquartile range 97.5-254.5] U/L, P < .001). Setting a cut-off value of 214 U/L for ALP yielded a sensitivity and specificity of 0.88 and 0.55, respectively, for diagnosing GCA. Multivariate analysis revealed that ALP was a significant independent variable in the complications of GCA (odds ratio, 25.2; P = .032). Conclusions: ALP can help distinguish GCA complications in patients with PMR.