Impacts of socioeconomic status on ambulatory care sensitive condition hospitalizations in RA

Persons with RA are at increased risk for ambulatory care sensitive conditions (ACSCs) hospitalizations. We assess if socioeconomic status (SES) modifies this association.

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 categorized into quintiles (Q1 privileged to Q5 deprived). Crude and adjusted incidence rate ratios (IRRs) 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.

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), whereas cases 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.

Socioeconomic deprivation and RA case status independently elevate the risk of an ACSC hospitalization.