A Streamlined Diagnostic Process Improved the Outcomes of Patients with Adult-Onset Still’s Disease: A Single-Center Retrospective Observational Study

Introduction The diagnosis of adult-onset Still’s disease (AOSD) is often delayed due to its clinical heterogeneity and lack of pathognomic features. Hence, there is an unmet need for an efficient diagnostic process. The major aim of this study was to compare the differences in disease outcomes between two groups of AOSD patients with and without implementation of the streamlined diagnostic process (SDP). Methods Of 172 febrile patients with skin rash and/or arthralgia, 112 individuals had AOSD. The tentative diagnosis of AOSD or non-AOSD was made with or without the SDP implementation. The selection criteria for AOSD outcomes analysis were as follows: (1) age at study entry older than 20 years, (2) fulfillment of the Yamaguchi criteria for AOSD diagnosis, and (3) a follow-up period longer than 6 months after initiation of therapy. Three outcome parameters were evaluated, including diagnosis lag period, the proportion of “early diagnosis,” and the proportion of achieving disease remission after a 6-month therapy. Results The SDP was implemented for expediting AOSD diagnosis in 41 (36%) enrolled patients (SDP-implemented group). The diagnosis lag period was significantly shorter in the SDP-implemented group (median 2.0 weeks, interquartile range [IQR] 1.0–2.5 weeks) than in the non-SDP-implemented group (4.0 weeks, IQR 2.0–6.0 weeks, p < 0.001). A significantly higher proportion of “early diagnosis” was also found in the SDP-implemented group (75.6%) compared with the non-SDP-implemented group (33.8%, p < 0.001). We revealed a significantly higher proportion of achieving remission in the SDP-implemented group (85.4%) compared with the non-SDP-implemented group (67.6%, p < 0.05). Logistic regression analysis revealed SDP implementation as a potential predictor of achieving disease remission. Conclusions Implementing an SDP for expediting diagnosis could improve outcomes for AOSD patients. This diagnostic process increased the early diagnosis rate and led to a higher disease remission rate. However, the beneficial effects of SDP implementation need further external validation.