The clinical course of multiple sclerosis patients in Hong Kong

Background Multiple sclerosis (MS) has a low prevalence in Hong Kong. Objective To reassess MS prevalence in Hong Kong and to examine associated risk factors for relapsing–remitting type MS patients to reach Kurtzke's Extended Disability Status Scale (EDSS) of 6.0, i.e. when walking aid was needed. Design Retrospective observational study on MS patients over 11 years. Setting Three tertiary hospitals in Hong Kong. Results A hundred and six patients were recruited. Female to male ratio was 3.2:1 and the prevalence was 4.8 per 100,000. 95 were relapsing–remitting (RR) type. The mean disease duration was 12.7 years (range: 1–45 years) and the duration of follow up was 11.0 +/− 0.8 (mean +/− SE) years. The initial mean EDSS was 1.59 and the latest mean EDSS was 4.26. 38 (40%) RR type MS patients progressed to EDSS 6.0 after a mean duration of 6.0 years. With Cox regression analysis, patients with older age (> 35y) of onset (HR 2.57; 95% CI:1.29–5.11), higher EDSS of 2.0 or more upon presentation (HR 2.19; 95%CI: 1.12–4.26) were associated with progression to EDSS of 6.0, while there was a tendency towards slower disease progression for patients initially presenting with optic symptoms (HR 0.52; 95%CI: 0.23–1.16). The number of relapses and use of interferon could not be shown to have significant effect on disease progression. Conclusions The local period prevalence ratio of MS was 4.8 per 100,000. Older age of onset and higher EDSS upon initial presentation were independent predictors for progression to EDSS of 6.0.