Background/Purpose: Studies have reported differences in healthcare utilization and outcome among different socioeconomic and ethnic groups. Complications like atherosclerotic cardiovascular diseases (ASCVD) have been documented to be higher among the African-American population and this disparity is more pronounced in the population with connective tissue disease. Similar disparities based on racial/ethnic background have been reported among treatment options for rheumatoid arthritis (RA). We tried to gain an insight into the differences in hospitalization outcomes among RA patients as per different socioeconomic and demographic variables utilizing a large US inpatient database.

Methods: We selected patients aged ≥18 years with and without RA to compare the differences in mortality, length of stay, cost of hospitalization and ASCVD incidence among different race, gender, type of insurance and income quartile range (Table 1). Patients with RA were selected based on ICD-9 codes (714.0, 714.1 and 714.2). Patients with concomitant diagnoses of SLE, polymyositis, dermatomyositis and systemic sclerosis were excluded. We used Nationwide Inpatient Database from 2009 to 2011. STATA version 13.0 (College Station, TX) for analysis to accommodate for the complex design of survey sample data (NIS). NIS is the largest publicly available all-payer inpatient care database in the United States and is sponsored by the Agency for Healthcare Research and Quality as a part of Healthcare Cost and Utilization Project. 

Results: Mortality was most common among Caucasians (RA 2.4%, non-RA 2.37%, p=<0.0001), females (RA 2.67 %, non-RA 2.75%, p=<0.0001) and medicare patients (RA 2.7%, non-RA 3.32%, p=<0.0001). Mortality was lowest in the African American population among RApatients (1.97%, <0.0001) and in hispanics among the non-RA patients (1.58%, <0.0001). Length of stay was highest among the African-American (RA 5.53 days, non-RA 5.27 days, p=<0.0001), females (RA 5.19 days, non-RA 5.22 days, p=<0.0001) and the lowest income quartile (RA 5.27 days, non-RA 4.93 days, p=<0.0001). Patients with the highest income quartile, females and other races incurred the most charges during hospitalization. Incidence of ASCVD was highest among whites (RA 15.08%, non-RA 14.07%, p=<0.0001), females (RA 18.74%, non-RA 17.15%, p=<0.0001) and medicare patients (RA 16.9%, non-RA 19.9%, p=<0.0001).

Conclusion: Our findings indicate differences in clinical outcomes among different socio-economic groups in RA patients. Among patients with RA, we found higher rate of mortality and incidence of ASCVD among Caucasians. Similarly, females were found to have higher incidence of ASCVD, higher length of stay and hospital costs. Socio-economic and racial/ethnic influences may be important in interpreting differences in clinical outcomes relating to patients with RA.

  Table 1: Distribution of mortality, mean length of stay, mean hospital charge and ASCVD incidence by race, gender, type of insurance and income quartile range. ^± For year 2011:  Quartile 1 (1 – 38,999); Quartile 2 (39,000 – 47,999); Quartile 3 (48,000 – 63,999); Quartile 4 (64,000+)