Economic analysis of the use of Anti-DFS70 antibody test in patients with undifferentiated systemic autoimmune disease symptoms

Abstract

Objective. In patients with antinuclear antibodies (ANA) and undifferentiated features of systemic autoimmune disease, the coexistence of monospecific anti-dense fine speckled 70 (anti-DFS70) antibodies is associated with a lower risk of progression to overt disease. Therefore, they might help in correctly classifying ANA- positive patients and avoiding unnecessary followup diagnostic procedures. The aim of this study was to analyze the economic effect of the introduction of the anti-DFS70 antibody test in a hospital setting. Methods. A case-control study was performed to detect monospecific anti-DFS70 antibodies in ANA-positive subjects with undifferentiated features (cases, n = 124) and with a defined systemic autoimmune disease (controls, n = 290). Based on current clinical practice, a decision tree was developed to represent the disease course of patients with undifferentiated features in the subsequent 3 years. A budget impact analysis (BIA) was performed to estimate the effect of implementing the screening for anti-DFS70 antibodies in the case group on the total costs. A sensitivity analysis was conducted to calculate the effect of the uncertainty of the input variables on the results. Results. Among the 124 patients in the case group, 5 (4.0%) tested positive for anti-DFS70 antibodies versus 4/290 (1.4%) in the control group (p = not significant). The mean cost per patient under the current clinical practice decreased from -3274 to -3192 in our scenario. The BIA reports cost savings of -10,128. Conclusion. The introduction of anti-DFS70 antibody test would avoid unnecessary followup diagnostic procedures and minimize the use of health resources generated by suspicion of a potential systemic autoimmune disease.