Healthcare costs of systemic lupus erythematosus in New Zealand.

Objectives: This study aims to estimate the annual medical costs of systemic lupus erythematosus (SLE) in New Zealand (NZ).

Methods: SLE patients were linked to the Australia and New Zealand Dialysis and Transplant Registry, Pharmaceutical Collection, National Minimum Dataset, National Non-Admitted Patients Collection and Mortality Collection. National direct medical costs of SLE in 2006-2021 and annual costs per patient were estimated. Generalized linear model was used to examine the impact of various factors on medical costs, including ethnicity, gender, age, socioeconomic status and presence of end-stage kidney disease (ESKD).

Results: The annual national costs of SLE were stable over time, around NZ$12 million. The average costs were NZ$8,324 (US$5,277, €5,011) per patient per year, with the costs for patients with ESKD being nine times higher than patients without ESKD (NZ$47,143 vs NZ$5,091). The costs per patient for Māori and Pacific were both around twice the costs for European/Others (NZ$13,124 and NZ$11,842 vs NZ$6,153), but the difference attenuated after adjustment for ESKD and other factors. Among patients without ESKD, Asian, males and patients living in the most deprived areas were associated with higher costs. For patients with ESKD, Māori and patients living in the most deprived areas had higher costs.

Conclusions: The annual national costs of SLE were stable over time. The increase in pharmaceutical costs were offset by decrease in hospitalisation costs. Costs for patients with ESKD were nine times higher than costs for patients without ESKD. Interventions for slowing the disease progression and preventing ESKD can reduce medical costs.