OBJECTIVES: Rheumatoid arthritis (RA) is highly prevalent among US veterans. This study assessed health care costs and predictors of hospitalization among patients with RA in the US Veterans Health Administration (VHA) population (01APR2013-31MAR2018).

METHODS: Adult patients with ≥1 inpatient diagnosis code for RA (International Classification of Disease, 9^th/10^th Revision, Clinical Modification [ICD-9-CM] codes 714.0-714.4, 714.8, 714.9; ICD-10-CM: M05, M06, M08, M12) were identified (01APR2013-31MAR2017); the first diagnosis date was the index date. Non-RA patients were 1:1 propensity score matched to RA patients by age, sex, race, and index year. The index date for non-RA patients was randomly selected to reduce bias. Health care costs and hospitalizations during the 1-year post-index period were compared between RA and non-RA cohorts. Logistic regression was performed to identify predictors of hospitalization.

RESULTS: This study included 100,847 matched pairs. The mean age was 66 years; most patients were Caucasian (73.28%) and male (89.79%). Compared with non-RA patients, RA patients had a significantly higher mean Charlson comorbidity index (CCI) score (1.7 vs 1.1) and a higher proportion of patients with ≥1 hospitalization (9.4% vs 3.3%; all p<0.0001). Mean inpatient ($3,430 vs $1,181), outpatient ($6,396 vs $2,719), pharmacy ($1,951 vs $679), and total health care costs ($11,776 vs $4,579; all p<0.0001) were nearly three times higher for patients with vs without RA. Logistic regression analysis results revealed the following independent hospitalization predictors: upper-middle age (55-64 years) (odds ratio [OR]: 1.22, 95% confidence interval [CI]: 1.16-1.28), male (OR: 1.13, 95% CI: 1.04-1.22), African American (OR: 1.23, 95% CI: 1.07-1.41), and higher CCI scores (OR: 1.24, 95% CI: 1.23-1.26).

CONCLUSIONS: Over a 1-year period, RA patients in the US VHA population had more hospitalizations and higher economic burden than patients without RA. The risk of hospitalization was higher among older African American men with higher CCI scores.