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Original research
Multiple sclerosis mortality in New Zealand: a nationwide prospective study
  1. Ruth Leadbetter1,2,
  2. Michael MacAskill2,3,
  3. Daniell J Myall2,
  4. Bruce V Taylor4,
  5. Purwa Joshi1,
  6. NZMSPS group,
  7. Deborah F Mason2,3,5
    1. 1 Department of Neurology, Wellington Regional Hospital, Wellington, New Zealand
    2. 2 New Zealand Brain Research Institute, Christchurch, New Zealand
    3. 3 Department of Medicine, University of Otago, Christchurch, New Zealand
    4. 4 Menzies Research Institute, University of Tasmania, Hobart, Tasmania, Australia
    5. 5 Department of Neurology, Christchurch Hospital, Christchurch, New Zealand
    1. Correspondence to Dr Ruth Leadbetter, Department of Neurology, Wellington Regional Hospital, Wellington, New Zealand; rleadbetter20{at}gmail.com

    Abstract

    Background Mortality data from Europe and North America show a shorter life expectancy for people with multiple sclerosis (MS). It is not known if a similar mortality risk exists in the southern hemisphere. We analysed the mortality outcomes of a comprehensive New Zealand (NZ) MS cohort, 15 years postrecruitment.

    Methods All participants of the nationwide 2006 NZ MS prevalence study were included and mortality outcomes were compared with life table data from the NZ population using classic survival analyses, standardised mortality ratios (SMRs) and excess death rates (EDRs).

    Results Of 2909 MS participants, 844 (29%) were deceased at the end of the 15-year study period. Median survival age for the MS cohort was 79.4 years (78.5, 80.3), compared with 86.6 years (85.5, 87.7) for the age-matched and sex-matched NZ population. The overall SMR was 1.9 (1.8, 2.1)). Symptom onset between 21 and 30 years corresponded to an SMR of 2.8 and a median survival age 9.8 years lower than the NZ population. Progressive-onset disease was associated with a survival gap of 9 years compared with 5.7 years for relapsing onset. The EDR for those diagnosed in 1997–2006 was 3.2 (2.6, 3.9) compared with 7.8 (5.8, 10.3) for those diagnosed between 1967 and 1976.

    Conclusions New Zealanders with MS have a median survival age 7.2 years lower than the general population and twice the mortality risk. The survival gap was greater for progressive-onset disease and for those with an early age of onset.

    • multiple sclerosis
    • epidemiology

    Data availability statement

    Data are available on reasonable request. Requests for data should be made to the corresponding author, RL, and will be reviewed by our steering committee.

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    Data availability statement

    Data are available on reasonable request. Requests for data should be made to the corresponding author, RL, and will be reviewed by our steering committee.

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    Footnotes

    • Collaborators NZMSPS group: John F Pearson, Glynnis Clarke, David A Abernethy, Ernest Willoughby and Clive E Sabel.

    • Contributors Study concept and design: RL, DFM, MM, DJM and PJ. Data acquisition: DFM, BVT, RL, PJ and NZMSPS group. Data analysis and interpretation: RL, DFM, MM and DJM. Statistical analysis: MM and DJM. Drafting the manuscript: RL, DFM, MM and PJ. Critical revision of the manuscript for important intellectual content: RL, DFM, BVT, MM, DJM, PJ and NZMSPS group. Funding acquisition: DFM and RL. Study supervision: DFM and BVT. RL is responsible for the overall content as guarantor.

    • Funding This study was supported by the NZ Neurological Foundation (grant number 2024 CHF) and The Neurology Trust.

    • Competing interests None declared.

    • Provenance and peer review Not commissioned; externally peer reviewed.

    • Supplemental material This content has been supplied by the author(s). It has not been vetted by BMJ Publishing Group Limited (BMJ) and may not have been peer-reviewed. Any opinions or recommendations discussed are solely those of the author(s) and are not endorsed by BMJ. BMJ disclaims all liability and responsibility arising from any reliance placed on the content. Where the content includes any translated material, BMJ does not warrant the accuracy and reliability of the translations (including but not limited to local regulations, clinical guidelines, terminology, drug names and drug dosages), and is not responsible for any error and/or omissions arising from translation and adaptation or otherwise.