Fig. 1From: Cohort identification of axial spondyloarthritis in a large healthcare dataset: current and future methodsPositive predictive value and sensitivity of ankylosing spondylitis ICD-9 code for AxSpA. PPV = positive predictive value. *n = 156 Veterans with an AS ICD-9 code. **n = 75 Veterans with AxSpA who were not selected to the chart review sample specifically for an AS ICD-9 codeBack to article page