Impacts of socioeconomic status on ambulatory care sensitive condition hospitalizations in rheumatoid arthritis

OBJECTIVES: Persons with Rheumatoid Arthritis (RA) are at increased risk for ambulatory care sensitive conditions (ACSCs) hospitalisations. We assess if socioeconomic status (SES) modifies this association. METHODS: Individuals meeting a validated case definition for RA in a Canadian population-based administrative health dataset (years 2007-2023) were matched 1:4 by age and sex to general population controls. SES was determined using a combined material and social deprivation index derived from area-level census data and categorised into quintiles (Q1 privileged toQ5 deprived). Crude and adjusted incidence rate ratios (IRR) for ACSC admissions were estimated at 3- and 5- years following index date using zero-inflated Poisson regression models. Potential additive and multiplicative interactions were assessed. RESULTS: We identified 83,811 unique hospitalizations in 52,596 RA cases and 190,300 in 210,384 controls. ACSC-related admissions increased in frequency with greater levels of deprivation. RA cases with privilege had significantly higher rates of ACSC-related hospitalization compared with controls at 3 years (SES Q1: IRR 1.34, 95% CI 1.02-1.77; Q2: IRR 1.30, 95% CI 1.05-1.62) and 5 years (Q2: IRR 1.20, 95% CI 1.01-1.42)whereascases and controls with deprivation had similar incidence rates for ACSC admissions (3 years Q4: IRR 0.95, 95% CI 0.81-1.12; Q5: IRR 1.00, 95% CI 0.89-1.12; 5 years Q4: IRR 1.07, 95% CI 0.95-1.20; Q5: IRR 1.02, 95% CI 0.94-1.12). Interaction tests and Relative Excess Risk due to Interactions were non-significant. CONCLUSION: Socioeconomic deprivation and RA case status independently elevate the risk of an ACSC hospitalization.