Predictive Value of Serum Angiotensin-Converting Enzyme Titers in Sarcoid-Like Dacryoadenitis.

Abstract

To compare serum angiotensin-converting enzyme (sACE) titers in patients with newly diagnosed sarcoid-like dacryoadenitis and nongranulomatous dacryoadenitis. Retrospective comparative case series. Clinical details and presenting sACE titers were reviewed for patients with newly diagnosed sarcoid-like dacryoadenitis (SLD) and nongranulomatous dacryoadenitis (NGD). All sACE titers were expressed as a percentage of the upper end of normal range ("normalized"). Using Student t test, sACE titers for patients with unilateral SLD were compared with unilateral NGD and the sensitivity and specificity of sACE as a predictor for SLD calculated; this was repeated for patients with bilateral dacryoadenitis. The proportion of patients with raised sACE were compared in each group (Fisher exact test), and the mean sACE titers compared for these selected patients. For unilateral SLD the mean sACE was 97%, compared with 57% in NGD (p=0.0010), and the sensitivity of sACE titer was 42%, specificity 92%, positive predictive value 75%, and negative predictive value 73%. Area under curve from receiver operating characteristic analysis for unilateral dacryoadenitis was 0.78 (p=0.0040). In contrast, there was no significant difference for bilateral disease (SLD 148%, NGD 82%; p=0.33), and somewhat lower positive predictive value (54%), negative predictive value (71%) and area under curve (0.71; p=0.070). Although not significantly so with bilateral disease, the proportion of patients with raised sACE was consistently greater in SLD as compared to NGD-being highest with bilateral SLD (7/12 patients; 58%) and lowest in unilateral NGD (2/26; 8%). Seventeen of the 27 patients with SLD were later found to have systemic involvement: where systemic disease was present, the mean sACE levels were significantly different in unilateral (102%) and bilateral dacryoadenitis (209%; p=0.029) disease, whereas there was no difference in the absence of systemic involvement (sACE with unilateral dacryoadenitis = 86%, bilateral = 75%; p=0.72). Normalized serum titers of ACE are minimally predictive for SLD, whether unilateral or bilateral, with some false negatives and false positives in all groups. However, with unilateral dacryoadenitis, an sACE of >125% maximum range appears absolutely predictive for SLD, and >150% maximum range for bilateral disease.