Background/Purpose: Systemic Lupus Erythematosus (SLE) is associated with a high rate of hospitalizations and is the sixth highest reason for 30-day readmissions among all medical conditions in the USA. In SLE patients, lower socioeconomic status correlates with poorer disease outcomes and a higher mortality rate but whether poverty is a risk factor for hospitalization is not clearly understood.
To identify the impact of poverty as a risk factor for hospitalizations in SLE patients.

Methods: We designed a single center, retrospective study of SLE patients hospitalized to Strong Memorial Hospital in Rochester, New York. Billing data was analyzed to identify all hospitalizations that included an ICD-10 code for SLE as primary or secondary diagnosis for the period between July 1, 2013 and June 30, 2017. A diagnosis of SLE was confirmed by evaluating for the presence of American College Rheumatology Criteria or was assigned by a rheumatologist. The outcomes were high-risk patients (defined as those with 3 or more admissions per year) and we collected data on length of stay (LOS) and cost of admissions. The key independent variable was poverty based on the patient resident zip code. Areas of poverty were as defined by the Finger Lakes Health Systems Agency. Bivariate analysis followed by multivariable regression models that controlled for important patient-level confounders such as age, gender, race/ ethnicity, body mass index, disease activity measures (complements, dsDNA, Systemic Lupus International Collaborating Clinics Damage Index (SDI) and comorbidity index (CMI) were applied to assess the data.

Results: A total of 202 patients with SLE were admitted over the 4 year study period and 68 of these subjects were from zip codes associated with poverty. On bivariate analysis we found that patients living in the poverty associated zip codes were significantly more likely to be categorized as high risk patients (p=0.01) and were of African American origin (p=0.001). We also noted significantly higher median dsDNA levels among subjects from the areas associated with poverty (11.2) compared to patients from other zip codes (4.6) (p=0.01). No significant differences were noted for age, SDI, complement levels, total and average LOS as well as total and average cost of admissions between the two groups. We then created multivariable regression models to assess impact of poverty on the above mentioned outcomes of interest. Patients residing in areas with poverty associated zip codes were significantly more likely to be classified as high risk patients (OR 2.96; CI 1.09, 9.00; p=0.03) with higher SDI scores (OR 1.39; CI 1.07, 1.81; p=0.01). SDI was associated with significant risk for admissions (OR 1.26; P< 0.01), average cost above the median (OR 1.65; p< 0.01) and average LOS above the median (OR 1.37; p=0.01). Analysis focused on the African American population revealed that living in poverty areas remained a significant risk factor for hospitalization (p=0.04).

Conclusion: Socioeconomic factors and damage index are significant risk factors for hospitalizations in SLE patients. Early initiation of therapy, addressing the challenges of poverty and overcoming healthcare disparities are important goals to improve the health of lupus patients.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/poverty-and-systemic-lupus-international-collaborating-clinics-damage-index-sdi-are-significant-risk-factors-for-hospitalization-in-sle-patients/