Hospitalisation cost for paediatric osteomyelitis and septic arthritis in New Zealand.

Aim: Hospitalisation rates for paediatric bone and joint infection (BJI) in New Zealand (NZ) are among the highest globally. This study aims to quantify hospitalisation costs of BJI in 2018-2019.

Methods: National hospitalisation data from the NZ Ministry of Health was used to describe costs associated with all paediatric hospitalisations coded for osteomyelitis or septic arthritis in those aged <16 years. Data included age, ethnic group, area level deprivation, diagnosis-related-group coding, admission length and cost-weight. Readmissions up to 24 months following the initial encounter were analysed for associated costs.

Results: More than ten million dollars was spent on hospitalisation for paediatric BJI over the study period (NZ$10 819 474). There were 869 primary hospitalisations and 229 related readmissions. Median length of stay was 7.4 days (95% confidence interval 6.8-7.9). Re-admission costs were NZ$1 196 640 within 24 months following diagnosis. Higher median hospitalisation costs occurred for children residing in the most deprived versus least deprived neighbourhoods (NZ$12 126 vs. NZ$9010, P < 0.01). NZ Māori compared with non-Māori children had longer length of stay (8.4 vs. 6.3 days, P = 0.04), more complex and severe illnesses (53% vs. 17%, P < 0.01), and higher median hospitalisation costs (NZ$11 796 vs. NZ$9581, P = 0.03).

Conclusions: Direct BJI hospitalisation costs in 2018-2019 were NZ$10 819 474 with 11% of costs due to re-admission. Direct hospitalisation costs for paediatric BJI in NZ vary by deprivation and ethnic group. Illness complexity of paediatric BJI varies by ethnic group. Interventions are needed to reduce incidence and severity of these debilitating infections.