Application of the 2017 McDonald criteria for the diagnosis of multiple sclerosis after a first demyelinating event in patients from Argentina.

BACKGROUND

The 2017 McDonald criteria are based on data from Caucasian European and North American populations. It is unknown whether they are externally valid in Latin American populations.

OBJECTIVE

We aimed to analyze the sensitivity, specificity, predictive values, and diagnostic accuracy of the 2017 McDonald criteria in a cohort of patients with a first demyelinating event in Buenos Aires, Argentina.

METHODS

We determined if patients with a first demyelinating event presented dissemination in time and space according to the 2010 and the 2017 McDonald criteria. We calculated the sensitivity, specificity, positive and negative predictive values, and accuracy for both criteria sets to predict a second radiologic or clinical event. Survival analyses were performed to evaluate differences in time to a second event when we applied the 2010 or the 2017 McDonald criteria. We also conducted a genealogical interview in order to analyze ethnicity.

RESULTS

108 patients with a first demyelinating event were included. All patients were European descendants according to ethnic analysis. 67 patients fulfilled the 2017 McDonald criteria and 31 patients met the 2010 criteria, at baseline. 54 patients who fulfilled the 2017 McDonald criteria experienced a second event during the follow up period, while 25 patients who met the 2010 criteria had a new relapse or new MRI activity during this period. Sensitivity, specificity, positive and negative predictive values, and accuracy values for the 2017 McDonald criteria were 67,5%, 53,5%, 80,5%, 36,5%, and 63,8%. For the 2010 McDonald criteria the results were 31,2%, 78,5%, 80,6%, 28,5%, and 43,5%, respectively. Specificity increased after excluding patients treated with disease-modifying therapies prior to a second event. The Kaplan-Meier analysis showed that the 2017 McDonald criteria reduced time to a second event ten months compared with the 2010 criteria.

CONCLUSION

Compared to the 2010 criteria, the 2017 McDonald criteria were more sensitive but less specific in our patients. However after excluding patients who received disease-modifying treatment before a second event, the specificity of the 2017 McDonald criteria in our cohort increased to 87.5%.