Clinical usefulness of serum angiotensin converting enzyme in silicosis

Abstract

Introduction: Silicosis is an irreversible and incurable disease. Preventive measures to eliminate exposure are the only effective way to reduce morbidity and mortality. In such situations, having a biomarker for early diagnosis or to predict evolution would be very useful in order to improve control of the disease. The elevation of serum angiotensin-converting enzyme (sACE) in silicosis has been described in previous studies, although its relationship with severity and prognosis is not clear. Aims: To determine the levels of sACE in a cohort of patients with exposure to silica dust with and without silicosis, and to assess their impact on the prognosis of the aforementioned patients. Method: Prospective observational study on patients treated in a silicosis clinic from 2009 to 2018. sACE levels and pulmonary function tests were performed. Radiological progression was assessed in patients who had already had 2 X-rays of the thorax and / or two CT scans with at least a 1-year interval, from the time of inclusion in the study. Results: A total of 413 cases of silicosis were confirmed, as well as 73 with exposure to silica dust but without silicosis. The mean sACE level for healthy subjects was 27.5§7.3U/L, for exposed patients without silicosis it was 49.6§24.2U/L, for simple silicosis it was 57.8§31,3U/L and forcomplicated silicosis it was 74.5§38.6U/L. Patients with a higher sACE generally progressed radiologically during follow-up (73.3§38.0 vs. 60.4§33.7; p<.001) and so the category of silicosis changed (73,9§38.1 vs. 62.5§34.6; p<.021). Conclusions: sACE was elevated in patients with silicosis, and the greater its severity, the higher it was, which is associated with disease progression measured radiologically or as a category change of silicosis.