Increasing prevalence and incidence rates of multiple sclerosis in Kuwait.

Background: Kuwait was considered as low to intermediate risk area for MS.

Objectives: To determine the prevalence and incidence rates of MS among Kuwaiti nationals based on 2011 population census.

Methods: This cross-sectional study was conducted between October 2010 and April 2013 using the newly developed national MS registry in Kuwait. Patients with a diagnosis of MS according to 2010 revised McDonald criteria were identified. The crude, age- and sex-specific prevalence and incidence rates among Kuwaiti patients were calculated.

Results: 1176 MS patients were identified of which 927 (78.8%) were Kuwaitis and 249 (21.2%) were expatriates. Among Kuwaiti patients, female to male ratio was 1.8:1 with a mean age of 35.40 ± 10.99 years. The prevalence rate of MS was 85.05 per 100,000 persons (95% CI: 82.80 - 87.04). There was a peak in prevalence among patients aged 30-39 years. The incidence of MS was 6.88 per 100,000 persons (95% CI 5.52-8.55). Between 2003 and 2011, the incidence increased 3.22 and 2.54 times in women and men respectively.

Conclusion: Kuwait is considered a high-risk area for MS. The significant increase in prevalence and incidence rates may represent a true increase despite the improvement in case ascertainment and case definition.