Diagnostic value of angiotensin-converting enzyme levels for assessing organ involvement in sarcoidosis: A retrospective single-centre study

Background: Angiotensin-converting enzyme (ACE) is the most widely studied biomarker in sarcoidosis; however, its association with epidemiology and multi-organ involvement remains unclear. The aim of our study was to analyse whether elevated ACE levels are associated with epidemiological factors, as well as with pulmonary, extrathoracic, and multi-organ involvement in patients with sarcoidosis. Methods: A retrospective single-centre study was conducted on patients diagnosed with sarcoidosis between 2000 and 2024. Multi-organ disease was defined as involvement of three or more organs, and elevated ACE levels were defined as values equal to or greater than 50 IU/L. Results: A total of 177 patients were analysed, of whom 117 patients (66.1%) presented with elevated ACE levels at the time of diagnosis. A significant relationship between elevated ACE levels and multi-organ involvement was observed (OR = 4.99 [95% CI 1.56-15.96]), while White patients (OR = 4.9 [95% CI 1.04-23.25]), skin involvement (OR = 2.55 [95% CI 1.27-5.12]), and age (OR = 1.02 [95% CI 1.0-1.04]) were associated with normal ACE levels. A receiver operating characteristic (ROC) curve to differentiate multi-organ from limited involvement yielded an area under the curve (AUC) of 0.788, with 86.2% sensitivity and 36.5% specificity using the conventional cut-off (50 IU/L). Conclusions: Patients with sarcoidosis and multi-organ involvement had elevated ACE levels. In contrast, older age, White race/ethnicity, and skin involvement were associated with ACE levels within the reference range.