A prospective observational study validating the CET score as a screening tool in suspected DRESS syndrome

Background Drug reaction with eosinophilia and systemic symptoms (DRESS) is an idiosyncratic severe cutaneous adverse reaction that may be potentially life-threatening. Recently, a simple scoring system for the early screening of DRESS patients was derived by combining hsCRP levels, the eosinophil count, and the total body surface area (CET score). The objectives of this study were validating the CET score, and calculating its lead time advantage and cost-benefits compared to RegiSCAR scoring. Methods This is a prospective observational case-control study, where 110 consecutive patients diagnosed with drug-induced maculopapular exanthema (MPE) were recruited during the 18 months of the study period. Patients were classified as cases (DRESS) and controls (MPE) using RegiSCAR score cut-off 2 (possible DRESS). They were also simultaneously screened using the CET score, based on which patients were classified as positive or negative. They were subsequently followed up on Day 15 for a second comparison and assessment of lead time and at 3 and 6 weeks to evaluate clinical response. Results Seventy cases and 40 controls were recruited. At a cut-off of >2.12, the CET score had a sensitivity of 94.3%, a specificity of 60%, a positive predictive value (PPV) of 80.5%, and a negative predictive value (PPV) of 85.7%. The median delay in diagnosing DRESS using RegiSCAR was around 14.5 hours. There was a median cost benefit of 12.1 USD in favor of the CET score. Conclusions The CET score had good diagnostic performance in screening DRESS patients with a lead time of 14.5 hours and fewer costs incurred.