Identifying multiple sclerosis in linked administrative health data in Aotearoa New Zealand.

Abstract

Aim: The 2006 New Zealand national multiple sclerosis (MS) prevalence study (NZMSPS) provided invaluable information about the prevalence of MS in Aotearoa and characteristics of people with this debilitating condition. This study aimed to update the NZMSPS by identifying people with MS using linked administrative health records.

Methods: Cases of MS were identified from hospitalisation, pharmaceutical dispensing, needs assessments for older adults and disability support records between January 1988 and June 2022. MS prevalence was estimated, and characteristics described and compared by sub-groups.

Results: A total of 7,890 people (73% female) with MS were identified across the study period. The estimated crude national prevalence of MS in 2022 was 96.6 per 100,000 (72.4 in 2006). MS prevalence exhibited a strong latitudinal gradient. Estimated age-adjusted prevalence was highest for Europeans (124.7 per 100,000), followed by Middle Eastern/Latin American/African (MELAA) (85.5), Māori (41.8), Asian (16.8) and Pacific peoples (11.1) ethnic groups.

Conclusion: Characteristics of MS cases were broadly similar to previous research, excepting a greater estimated prevalence among Māori, and a lower relative estimated prevalence for Auckland than surrounding regions. Linked administrative health data can be used to identify people with MS in Aotearoa, providing a mechanism for further research.