Previous studies have shown a significant shortening of time from multiple sclerosis (MS) onset (first relapse) to diagnosis in parallel with the adoption of new diagnostic criteria. However, the observation was not evaluated in Latin America.
The objective of the study was to study the interval from first symptom of MS to the date of diagnosis in relation to the introduction of upgraded MS diagnostic criteria in a Latin American population.
Cross-sectional study based on a self-reported survey. Patients with MS completed a regional survey in 12 Latin American countries. To be included, date of disease onset (first relapse) and date of diagnosis (confirmed disease) should be completed. Survival probabilities were evaluated for 5 diagnosis epoch groups according to the diagnostic criteria advised at the time: group 1- 1983-2000 Poser; group 2- 2001-2004 McDonald's first version; group 3- 2005-2009 revisions of 2005; group 4- 2010-2016 revisions of 2010; and group 5 -2017-2019 revisions of 2017.
1434 patients were included. 1108 (75%) females, mean age at study entry 39 ± 11 years. The mean time since disease onset to diagnosis in group 1 was 21 ± 8 months; in group 2, 19 ± 7 months; in group 3, 16 ± 10 months; in group 4, 9.6 ± 8.5 months and in group 5, 8.2 ± 10 months. Significant differences were observed between groups 1, 2, 3 vs. 4 and 5 (p<0.001) while no differences were observed between group 4 and 5 (p=0.08).
This study showed a significant shortening of time from MS onset to diagnosis in parallel with the adoption of new diagnostic criteria in Latin America in recent decades.