This project utilised the validated glucocorticoid toxicity index (GTI) tool to assess the morbidity of glucocorticoid-use in patients with autoimmune bullous disease. In particular, the study investigated the nature and prevalence of glucocorticoid-induced myopathy.

This study is an multi-centre observational trial. Patients with AIBDs are recruited based on the criteria: an age of eighteen years or above; a new or established diagnosis of autoimmune bullous disease confirmed by clinical assessment, histopathology, immunofluorescence, and enzyme-linked immunoassay (ELISA) or biochip testing; new or current use of oral glucocorticoids for the treatment of autoimmune bullous disease (Group 1, active treatment group), patients with receipt of previous oral glucocorticoid use with no current use (Group 2, steroid-sparing control group) or patients who had ceased glucocorticoids during the study (Group 3, ceased steroid group) ; attendance of at least one baseline visit (V1) and one follow-up visit during the study period; and, the provision of capacitated and informed consent.

Patients are considered for enrolment based on inclusion criteria after attendance at a bullous disease clinic at a participating study site. At the baseline visit (V1), patients are comprehensively interviewed for demographic factors (age, gender), pre-existing medical conditions, and past and current medications. Patients attend regular follow-up visits at three-month intervals, to a maximum follow-up period of 15 months (V6). Treatment plans, including glucocorticoid dose, are determined by accredited medical professionals based on the clinical condition of the patient.

The Glucocorticoid Toxicity Index (GTI) tool (Figure 1) is used to evaluate glucocorticoid toxicity at all visits, including in dermatologic, neuropsychiatric, musculoskeletal, endocrine and metabolic domains.

Myopathy was measured and graded in accordance to the GTI.

Patients were divided into three groups: Group 1 (control) comprised of patients was comprised of who were not exposed to glucocorticoids during the study period, Group 2 comprised of patients whose glucocorticoid dose was ceased during the study period. Patients who continued on glucocorticoid treatment for the duration of the study period formed the third group.

Inclusion Criteria:

• An age of eighteen years or above.
• A new or established diagnosis of autoimmune bullous disease confirmed by clinical assessment, histopathology, immunofluorescence, and enzyme-linked immunoassay (ELISA) or biochip testing
• New or current use of oral glucocorticoids for the treatment of autoimmune bullous disease (Group 1, active treatment group), or patients with receipt of previous oral glucocorticoid use with no current use (Group 2, steroid-sparing control group)
• Attendance of at least one baseline visit (V1) and one follow-up visit during the study period; and, the provision of capacitated and informed consent.

Exclusion Criteria:

• Inability to consent.
• Under 18 years of age.

Patients with autoimmune bullous disease who regularly attend a bullous clinic as part of their regular care. Patients who have either used glucocorticoids in the past or are currently using glucocorticoids.