Time interval between disease onset and MS diagnosis during the last decades in Latin America

The objective was to evaluate the interval from first symptom of multiple sclerosis (MS) to diagnosis with the introduction of MS diagnostic criteria in a Latin American (LATAM) population.

Patients with relapsing-remitting MS (RRMS) completed a survey in 12 LATAM countries. Date of disease onset (first relapse) and date of diagnosis (confirmed disease) were required. Survival probabilities were evaluated for 5 diagnosis epoch groups: 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.

1188 (75.6% females) patients were included. Mean time from 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 groups 4 and 5 (p=0.08).

We observed a significant shortening of time from MS onset to diagnosis with the adoption of new diagnostic criteria in LATAM.