Time interval between the onset of symptoms and diagnosis of multiple sclerosis and the influential factors: A national registry-based study.

Objective: The time to diagnosis of multiple sclerosis (MS) is of great importance for early treatment, thereby reducing the disability and burden of the disease. The purpose of this study was to determine the time from the onset of clinical symptoms to the diagnosis of MS and to evaluate the factors associated with a late diagnosis in Iranian MS patients.

Methods: The present cross-sectional study was conducted on patients with MS who were registered in the National MS Registry System of Iran (NMSRI).

Results: Overall, 23291 MS patients registered in 18 provinces of Iran were included in this study. The mean (standard deviation) interval between the onset of the disease and diagnosis of MS was 13.42 (32.40) months, and the median was one month. The diagnostic interval of 41.6% of patients was less than one month, and 14.8% of them had a one-month time to diagnosis. Patients with an age of onset below 18 years and those diagnosed after the age of 50 years had a longer time to diagnosis (P<0.001). Patients with primary progressive MS (PPMS) had the longest time to diagnose and those with relapsing-remitting MS (RRMS) had the shortest time (P<0.001). The results of negative binominal regression showed that the average rate of delay in diagnosis in women was 12% less than that in men. The average delay in diagnosis in patients with a positive family history of MS was 23% more than that in others. The rate of delay in the diagnosis of patients with PPMS and secondary progressive MS was 2.22 and 1.66 times higher, respectively, compared with RRMS.

Conclusion: The findings of the present study revealed that more than half of the MS patients were diagnosed within a one-month interval from the symptom onset, which is an acceptable period. More attention should be paid to patients' access to medical facilities and MS specialists.