OBJECTIVES: While adverse effects are associated with steroids, quantifying steroid toxicity is challenging. Evidence can be expanded by adapting the Glucocorticoid Toxicity Index (GTI) algorithm, used primarily in clinical trials, to retrospective datasets. The objective of this study was to quantify steroid toxicity in myasthenia gravis (MG) with GTI-Metabolic Domains (GTI-MD) using electronic health records.

METHODS: Using US-based Optum® de-identified Electronic Health Record data set (Optum® EHR) (Jan 2013-Dec 2022), adults with MG (≥2 MG diagnoses ≥30-≤730 days apart between Jan 2014 and Sep 2021) were identified. Index dates were defined as first steroid for steroid initiators (MG-SI) and assigned by age/gender-matched counterpart in MG-SI for steroid-naïve patients (MG-SN). Patients having lab values for main criteria required for GTI-MD (body mass index, blood pressure, glucose levels, lipid levels) within a 14-day period during both the baseline (1 year pre-index) and follow-up period (1-year post-90-day steroid exposure period post-index) and fulfilling other GTI-MD criteria were included. Baseline characteristics including age (at index) and Charlson Comorbidity Index (CCI, 1-year pre-index) were assessed. GTI-MD scores (Aggregate Improvement Score [AIS] and Cumulative Worsening Score [CWS], higher scores represent higher toxicity) were evaluated at first set of labs in follow-up.

RESULTS: Overall, 27,157 patients with MG were identified in the study period. After applying all criteria, 377 MG-SI and 305 MG-SN patients were identified as eligible for GTI-MD analysis. The mean (SD) age was 68.7 (10.3) and 71.5 (9.0) years, and CCI (SD) was 2.6 (2.2) and 2.2 (1.9), respectively, for MG-SI and MG-SN cohorts. GTI-MD (SD) scores were higher in MG-SI versus MG-SN (AIS: 4.9 [34.5] vs. 1.9 [34.3], p=0.27; CWS: 22.6 [22.8] vs. 18.7 [21.2], p=0.023).

CONCLUSIONS: Our results suggest that steroid toxicity in patients with MG is quantifiable by applying GTI-MD to retrospective data. Future studies can evaluate steroid toxicity using GTI-MD in various therapy areas.