This is a monocentric, prospective, observational, non-interventional study. Enrolled patients were assessed during 3 visits over a year, with measurement of the GTI, medication dosage, measures of disease severity, and adverse event unit (AEU). The GTI aggregate improvement score (GTI-AIS) measures the change in GC toxicity between two time points, while the cumulative worsening score (GTI-CWS) measures cumulative GC toxicity.

At the end of data collection, 50 patients were enrolled, 46 had completed visit 2 and 41 had completed visit 3. At baseline, patients received a median daily dose of Prednisone of 20 mg (range 10-60 mg). Interim analysis with a subset of patients at the second visit showed absence of linear correlation between the daily Prednisone dosage and the GTI-AIS or GTI-CWS, but a positive linear relationship between the GTI-CWS and measures of disease activity, including the MG-Activites of Daily Living (Spearman’s ρ 0.61; p-value 0.001). At last visit, the median daily Prednisone dosage was 10 mg (range 0-40 mg) and the median change in Prednisone dosage since baseline was -7.5 mg (range -47.5 to +30 mg).  The median GTI-AIS since baseline was 23.5 (range -245 to 277) and the median GTI-CWS was 74 (range 0 to 326). The median change in AEU score since V1 was 0 (range -21 to +15). 

At study completion, most patients had a reduction in daily Prednisone dosage, but the median GTI scores increased, suggesting that additional factors than daily prednisone dosage impact GC toxicity. Final analysis will be presented, including correlations between the GTI scores with GC dosage, AEU, and measures of disease activity.