Proposal of a new diagnostic algorithm for adult-onset Still's disease.

OBJECTIVE: This study was performed to develop a new diagnostic algorithm for adult-onset Still's disease (AOSD). METHODS: We conducted a multicenter prospective nationwide case-control study in tertiary Internal Medicine, Rheumatology, and Infectious Diseases departments, to include successively patients with suspected AOSD based on the presence of two or more major criteria of Yamaguchi and/or Fautrel classifications. Patients were classified as AOSD or controls according to a predefined procedure. A receiving operating characteristic curve was used to determine the best cutoff value of the points-based score for disease classification. A diagnostic algorithm was developed to help the physician in the diagnostic approach. RESULTS: A total of 160 patients were included, 80 patients with AOSD and 60 controls with different diagnoses. Twenty patients with incomplete data were excluded. In the multivariate analysis, 6 items remained independently associated with AOSD diagnosis: typical rash (OR: 24.01, 3 points), fever ≥ 39 °C (OR: 17.34, 3 points), pharyngitis (OR: 10.23, 2 points), arthritis (OR: 9.01, 2 points), NLR ≥ 4 (OR: 11.10, 2 points), and glycosylated ferritin ≤ 20% (OR: 1.59, 1 point). AOSD should be considered if the patient satisfies 7 points with a sensitivity of 92.5%, specificity of 93.3%, and accuracy of 92.8% (area under the curve (AUC): 0.97 [95% CI: 0.94-0.99]). The present points-based score was more accurate and sensitive than the Yamaguchi classification (78.8%, 92.5%, p = 0.01) and Fautrel classification (76.3%, 92.5%, p = 0.004). A typical rash associated with a points-based score ≥ 7 points leads to a very likely disease. CONCLUSION: The proposed new algorithm could be a good diagnostic tool for adult-onset Still's disease in clinical practice and research. Key Points • A diagnostic algorithm was performed to help the physician in the diagnostic approach of AOSD. • The points-based score included in this algorithm had a high sensitivity and accuracy. • This diagnostic algorithm can be useful in the clinical research.

Validation of the neutrophil-to-lymphocyte ratio as a new simple biomarker of adult onset Still's disease: A STROBE-Compliant prospective observational study.

This study was performed to investigate the role of neutrophil-to-lymphocyte ratio (NLR) in the diagnosis of adult onset Still disease (AOSD) and its performance to improve the sensitivity of the classifications criteria (Yamaguchi and Fautrel Classifications). We conducted a multicenter prospective nationwide case-control study in Internal medicine, Rheumatology and Infectious disease departments, to include successively patients with suspected AOSD (2 or more major criteria of Yamaguchi or Fautrel classifications). All clinical and biological features were collected in a consensual and standardized clinical assessment at baseline and during follow-up. A receiving operating characteristic (ROC) curve was used to reassess the cutoff value of NLR. After determination of the cutoff value for NLR by ROC curve, 2 composite sets (Yamaguchi classification + NLR as a major criterion and Fautrel classification + NLR as a major criterion) were performed and evaluated. One hundred sixty patients were included, 80 patients with AOSD and 60 controls with different diagnoses. Twenty patients with incomplete data were excluded. The cutoff value for NLR equals 4 (area under the curve, AUC: 0.82). The NLR was ≥ 4 in 93.7% (75/80) of AOSD patients with a sensitivity of 93.8% and specificity of 61.7%. The association of NLR as a major criterion with the classification of Yamaguchi or Fautrel improved their sensitivity, respectively for Fautrel (76.3% to 92.5%, P = .004) and Yamaguchi (78.8% to 90%, P = .05). This study validates the NLR as a good simple biomarker of AOSD with a cutoff value of 4 and high sensitivity (93.8%). The addition of NLR (NLR ≥ 4) as a major criterion to the classifications (Yamaguchi and Fautrel) improved significantly their sensitivity and accuracy.