Background The first autochthonous reports of Chikungunya fever (CF) in Brasil was confirmed in 2014, and by December 2016, there were 263.980 probable cases of CF, 55.03% confirmed. According to recommendations of the Ministry of Health (MH) of Brazil, in an established epidemic situation, the diagnosis of CF should be made by appliyng clinical and epidemiological criteria. There is no indication for the serology for Chikungunya virus (CHIKV) in the acute phase, except in atypical cases and complicated clinical situations, which may generate doubts in clinical practice about the correct diagnosis of these patients.

Objectives The objective of this study was to evaluate the concordance of the clinical and epidemiological criteria with the serology results for CHIKV in a cohort of patients with CF.

Methods The multicenter cohort CHIKBRASIL from the Northeast of Brazil has enrolled CF patients with joint manifestations since April 2016, using as inclusion criteria the presence of fever and arthralgia/arthritis in a patient residing or who had visited an endemic or epidemic area within 15 days prior to the onset of symptoms. For the present study, we selected patients in which IgM and/or IgG serology was performed, regardless of the results. For the analysis of agreement with the serology, the most characteristic symptoms of CF were used individually (fever, arthritis/arthralgia or exanthema) and three models of association of symptoms were created: (1) fever and arthralgia; (2) fever and arthritis; (3) fever, arthralgia/arthritis, and exanthema. The sensitivity (SENS), specificity (SPEC), positive predictive value (PPV) and negative predictive value (NPV) of the criteria were also assessed, with the serology result considered the gold standard.

Results A total of 143 patients were evaluated, 119 (83.2%) of which were female, with a mean age of 53.89 years (± 13.5); 52.4% of the cases were in the subacute phase of the disease (15 days to 3 months) and 42.7% were in the chronic phase (over 3 months). The IgM positivity was observed in 95.1% of cases and IgG in 71.67%. The concordance rate between the IgM serology or combined positive serology (IgM or positive IgG) was over 80% for any of the symptoms/symptoms model analyzed, as well as the SENS and PPV of the symptoms/ symptoms model, which was over 95% in all situations evaluated. The concordance rate for IgG serology ranged from 51.9 to 72.1%. Model 1 presented the highest agreement with the result of positive combined serology.

Conclusions During an epidemic situation, the use of clinical and epidemiological criteria shows high agreement with the serology result, regardless of the combination of symptoms presented, with high sensitivity and positive predictive value.

Disclosure of Interest None declared