Background/Purpose: Antimalarials (AMs) reduce disease activity and improve survival in patients with systemic lupus erythematosus (SLE) and are recommended regardless of disease severity. Prior studies using mostly patient self-reported medication data showed that AMs are not universally prescribed. Using a real-world electronic health record (EHR) cohort, we investigated if patient or prescriber characteristics impacted AM prescribing frequency in SLE.

Methods: We identified potential SLE cases from a de-identified EHR with over 2.8 million subjects using a previously validated and published algorithm. A subject was a case if diagnosed with SLE by a specialist (rheumatologist, dermatologist, or nephrologist). Subjects excluded had alternative autoimmune diagnoses (i.e. cutaneous or drug-induced lupus), uncertainty in diagnosis, or missing notes. On chart review, we collected current age at time of analysis, sex, race, presence of SLE nephritis, and specialist managing SLE. SLE nephritis was defined as a positive renal biopsy or clinical diagnosis by a specialist. We assessed for ever use of AMs from inpatient and outpatient electronic prescribing and natural language processing that searched for medications in clinic notes and phone messages. We evaluated for differences in SLE cases prescribed AMs vs. those not prescribed using the Mann-Whitney U test for continuous variables and chi-square or Fisher’s exact test for categorical variables.

Results: We identified 566 cases confirmed on chart review. The SLE cases had a mean current age of 50 ± 18 years and were predominantly female (89%) with race breakdown of 63% Caucasian, 30% African American, 5% Hispanic, and 2% Asian. Of the 566 cases, 534 (94%) patients were ever prescribed an AM. Of the 32 (6%) patients not prescribed an AM, no contraindications were found on chart review. There were no differences in sex or race between SLE cases prescribed AMs vs. cases who were not (Table 1). SLE cases prescribed AMs were younger compared to cases not prescribed AMs (49 ± 18 vs. 57 ± 21, p = 0.05). SLE cases who primarily saw a nephrologist were less likely to have AMs prescribed compared to cases who saw a rheumatologist or dermatologist (64% vs. 98% vs. 100%, p < 0.001). SLE nephritis cases trended towards having less AMs prescribed compared to cases without nephritis (91% vs. 95%, p = 0.06).

Conclusion: Using a large EHR cohort, we found 94% of SLE patients were ever prescribed an AM. Our high rate of AM prescribing compared to prior studies suggests that prescribing AMs is becoming more standard practice. SLE patients that were older, primarily followed with a nephrologist, and had nephritis were less likely to have AMs prescribed. Recognizing prescribing practices for AMs in SLE can target future quality improvement efforts.

Table 1.

*Mann-Whitney U test for continuous variables and chi-square or Fisher’s exact test for categorical variables.

^£47 cases had missing race data and were not included.