Trends in thoracic spine injury rates in New Zealand: an eleven-year (2013– 2023) analysis of ACC claims

background: This study examines national trends in thoracic spine injury (TSI)–related claims in New Zealand over an 11-year period (2013–2023), with a focus on incidence patterns by sex, age group, injury type and ethnicity. methods: A descriptive longitudinal study design was used to analyse 11 years’ (2013–2023) data from the Accident Compensation Corporation (ACC). TSIs were grouped into fractures/dislocations, soft tissue injuries and pain syndromes. Incidence rates per 100,000 population were calculated using Stats NZ Tatauranga Aotearoa denominators. Trends were explored using descriptive analyses, population pyramids and heatmaps and modelled using Poisson and negative binomial regression to estimate annual percent change (APC). Forecasts to 2033 were generated using time-series models. results: Between 2013 and 2023 there were 1,003,713 new TSI claims. From 2013 to 2023, the incidence of TSI increased from 1,749 to 1,901 per 100,000 (z= -10.49, p<0.001). Our findings demonstrate that females had more claims than males. Modelled APCs were +0.32% (95% CI: -0.29% to +0.94%) for males and +0.25% (95% CI: -1.22% to +1.74%) for females, both non-significant. Fractures (APC: +1.24% [95% CI: +0.13 to +2.35, p=0.028]) accounted for only 1.8% of claims (n=18,334) compared to soft tissue injuries (n=981,796). However, the APC was non-significant for soft tissue injuries. The highest burden occurred in the 30–54 age groups. In terms of ethnicity, European and Asian groups had higher TSI rates than Māori and Pacific peoples. conclusion: TSIs have increased modestly over the past decade. The burden varies by sex, age and ethnicity. These findings support targeted prevention with implications for workforce health and equity-focused policy planning.