Epidemiological study of multiple sclerosis in Central America and the Caribbean (ENHANCE study): partial results from Costa Rica

Aim: This study aimed to describe the incidence and analyze the main demographic, epidemiological, clinical, diagnostic and treatment characteristics, as well as the presence of known risk factors and prognoses in Costa Rican patients with multiple sclerosis, treated in three hospitals, and who participated in the international study called ENHANCE.

Methods: The study was observational in nature, the medical records of patients over 18 years of age diagnosed with multiple sclerosis treated in three hospitals of the Costa Rican Social Security Fund, specifically the San Juan de Dios Hospital, the San Rafael de Alajuela Hospital and the San Carlos Hospital, during the period between January 2014 and December 2019, were retrospectively analyzed. All cases were used to determine clinical and sociodemographic characteristics, while only new cases from the study period were taken into account for incidence calculations. Clinical and treatment outcomes were obtained from a subset of patients with active follow-up of at least 5 years.

Results: A total of 147 cases were registered, of which 72 were new in the study period and 75 were incident or prevalent in 2014 that had documented follow-up of at least 5 years. The mean age at symptom onset was 31.9 years and 35.0 years at diagnosis. A predominance of cases was found in the female sex 69.4% (n=102) and the patients presented a variable score on the Extended Disability Scale that ranged from 0 to 8.5. The annual incidence in the population analysed varied between 0.32 and 1.28 cases per 100,000 inhabitants. The main clinical form identified was relapsing-remitting 87.8% (n=129) and the main reported impairments were motor and sensory. The most frequent central lesions documented in magnetic resonance imaging were periventricular lesions (35% (n=45) and it was found that most patients had low levels of vitamin D. In relation to therapeutic management, a decrease in the use of traditional treatments (commonly called first-line) and an increase in the use of new or second-line alternatives, such as ocrelizumab and natalizumab, were observed.

Conclusion: The data obtained in the present study suggest that the population analyzed behaves in a similar way to what has been reported in other international studies and does not differ considerably from what has been previously reported in the country.