Evaluation of steroid toxicity using the Glucocorticoid Toxicity Index-Metabolic Domains instrument in adults with myasthenia gravis: a real-world study in the USA.

Aim: The Glucocorticoid Toxicity Index-Metabolic Domains (GTI-MD) has been utilized to assess steroid toxicity in clinical trials and practice but has not been applied previously to large datasets. The GTI-MD was used to investigate steroid toxicity in patients with myasthenia gravis (MG) using a large real-world dataset. Materials & methods: Steroid toxicity was assessed in adults with MG (≥2 diagnoses occurring between ≥30 and ≤730 days apart) using Optum® electronic health records. Patients were categorized into steroid-initiator (MG-SI) or steroid-naive (MG-SN) cohorts. The GTI-MD algorithm assessed changes in steroid toxicity during follow-up using vital signs and simple laboratory tests pertaining to toxicity in the body mass index, blood pressure, glucose tolerance and lipid metabolism domains. Changes in steroid toxicity were reported as cumulative worsening scores (CWS) and aggregate improvement scores (AIS).

Results

A total of 682 (MG-SI:377; MG-SN: 305) patients with MG were included. The potential for steroid toxicity at index date, as assessed by the GT-SNAPSHOT scores, was comparable between the cohorts at baseline (92.0 ± 31.1 vs 88.8 ± 32.8; p = 0.117). At follow-up, the MG-SI cohort had higher CWS scores than the MG-SN cohort (22.6 ± 22.8 vs 18.7 ± 21.2; p = 0.023) and were more likely to exceed the 10-point minimum clinically important difference (68% vs 59%; p = 0.016) and the 20-point threshold (44% vs 36%; p = 0.030). Patients with multiple steroid exposures had higher CWS (25.7 ± 24.8 vs 19.2 ± 19.9; p = 0.006) and AIS (9.6 ± 34.7 vs -0.3 ± 33.7; p = 0.005) values than one-time steroid users. Patients who received ≥20 mg/day of steroids (prednisone-equivalent) at index had higher CWS values (25.0 ± 23.0 vs 19.9 ± 22.3; p = 0.033) and AIS values (8.3 ± 32.9 vs 1.1 ± 35.9; p = 0.044) compared with those who received <20 mg/day of steroids.

Conclusion

The GTI-MD is a valuable and sensitive method for unmasking steroid toxicity in MG using large datasets to gather real-world evidence.