Background/Purpose: Antimalarials (AMs) improve survival in patients with systemic lupus erythematosus (SLE). Current guidelines suggest AMs for all SLE nephritis patients. Studies using patient-reported data showed AMs are not universally prescribed. Using a real-world electronic health record (EHR) cohort, SLE nephritis vs. non-nephritis patients were less likely to be prescribed AMs. We examined if patient or prescriber characteristics impact AM prescribing patterns.

Methods: Potential SLE cases were from a de-identified EHR with 2.8 million subjects using a previously validated algorithm of 4 or more counts of the SLE ICD-9 code (710.0) and antinuclear antibody (ANA) positive (titer ≥ 1:160) while excluding dermatomyositis and systemic sclerosis ICD-9 codes. A subject was a case if diagnosed with SLE by a specialist (rheumatologist or nephrologist). SLE nephritis was defined as positive renal biopsy or clinical diagnosis by a specialist. We assessed for current use of AMs as documented by a specialist’s note closest to October 1, 2015 (end of ICD-9 coding). We collected age at time of analysis, sex, race/ethnicity, specialist prescribing AM, and whether patients underwent dialysis or kidney transplant. The kidney function and blood counts closest to the specialist’s note date were recorded. We evaluated for differences in SLE cases currently prescribed AMs vs. those not using the Mann-Whitney U test for continuous variables and chi-square or Fisher’s exact test for categorical variables.

Results: Our validated algorithm identified 1147 potential SLE subjects with 977 chart-confirmed SLE cases and 244 SLE nephritis cases. Of the SLE nephritis cases, mean age was 43 ± 16 years with 89% female, 47% Caucasian, 44% African American, 6% Asian, and 3% Hispanic. Among cases, 81% were followed by a rheumatologist with 38% ever on dialysis and 21% receiving kidney transplant. Only 63% (n = 153) of SLE nephritis cases were current AM users. No retinopathy was noted in cases not prescribed AMs. There were no differences in sex or race between current vs. non-current users (Table 1). Current users were significantly younger than non-current users (p < 0.001). Patients were more likely to be prescribed AMs when followed by a rheumatologist vs. a nephrologist (76% vs. 37%, p < 0.001). Current vs. non-current users were less likely to be on dialysis (p < 0.001) and less likely to have had a kidney transplant (p < 0.001). Current vs. non-current users had significantly lower creatinine (p < 0.001), lower urine protein/creatinine ratio (p = 0.04), and higher hemoglobin (p < 0.01).

Conclusion: Using a large EHR cohort, only 63% of SLE nephritis cases are currently prescribed AMs. As AMs reduce renal damage in SLE nephritis, our results demonstrate an opportunity to target future efforts to improving adherence to guidelines for AM prescribing.

Table 1.

^aChi-square, Fisher’s exact test, or Mann-Whitney U test

^bBoth indicates followed by rheumatologist and nephrologist