Prognostic indicators for long-term disability in multiple sclerosis patients.

Background: Daily practice is still faced with uncertainty in predicting the long-term disability of multiple sclerosis (MS). Most information comes from northern hemisphere cohorts, but in South America this information is scarce, and race, genetic and environmental factors could play an important role in the heterogeneity observed in disease outcomes.

Methods: We evaluated 197 patients attending our MS Center gathering clinical and demographic information. Outcome measures analyzed were time from first clinical symptom to EDSS of 6, 7 and 8. For survival analysis we employed Cox regression models and the Kaplan-Meier method.

Results: Time to EDSS 6 was 25.83 years (95% CI 15.36-36.31), and 36.25 years (95% CI 20.72-51.78) for EDSS 7. Male sex was associated with a 4.63 and 4.69 fold increased risk to EDSS 6 and 7, respectively (p<0.001 and p=0.006). Motor and brainstem symptoms at onset were also associated with an 8.1 and 13.1 fold increased risk to EDSS 6, respectively (p=0.04 and p=0.01). The number of relapses in five and ten years of disease onset was associated with a slightly increased risk to EDSS 8 (1.28 and 1.19, respectively; p=0.032 and p=0.015).

Conclusions: Male patients presenting with frequent relapses, especially those with motor and brainstem involvement, deserve close observation and should be cautiously monitored to early signs of treatment failure.