Adult-onset Still's disease presenting as fever of unknown origin: a single-center retrospective observational study from China.

BACKGROUND

The aim of this study is to establish a clinical diagnosis model as a new evaluation indicator for the differentiation of adult-onset Still's disease (AOSD) and other fever of unknown origin disease (FUO).

METHODS

This is an observational case-control study between January 2010 and December 2018. Laboratory parameters of AOSD group (N=91), FUO group (N=89) and control group (N=81) including procalcitonin, C-reactive protein (CRP), ferritin, leukocyte, lymphocyte, neutrophil, lymphocyte proportion, neutrophil proportion, red blood cell distribution width (RDW), platelet and platelet parameters were collected. Descriptive statistics and logistic regression were performed to establish a model based on these laboratory variables.

RESULTS

After univariate screening, the variables including CRP, leukocyte, neutrophil, lymphocyte proportion, neutrophil proportion, ferritin and mean platelet volume (MPV) showed significant difference between AOSD and FUO groups, then a stepwise regression analysis was performed to establish a model based on these screened variables, at last ferritin, neutrophil and MPV were significantly different in the model. The results suggested that the higher value of ferritin and neutrophil, the lower value of MPV in the model indicated the higher risk to diagnose AOSD. Area under the curve (AUC) of the model was 0.909 (95% CI: 0.855-0.947), which showed high differential diagnostic value (sensitivity: 86.6%, specificity: 82.0%).

CONCLUSIONS

The diagnosis model of AOSD and other FUO was established, with an outstanding performance for differential diagnosis.