Associate Professor Rangi Kandane-Rathnayake

Australian researchers have proposed a new way to define severe, treatment-resistant lupus (srSLE), which could help doctors choose the right patients for trials of intensive new therapies.

Associate Professor Rangi Kandane-Rathnayake, from Monash University, told the EULAR congress that the lack of an agreed definition for srSLE had been a major barrier to trial design, patient selection and comparing results across studies.

The researchers tested 80 candidate definitions of srSLE in a dataset of 4106 patients and more than 42,000 clinic visits. Each definition combined measures of disease activity and treatment exposure.

They checked how well each definition predicted poor outcomes over 12 months, including flare, organ damage and failure to reach a state of low disease activity (LLDAS).

The proportion of patients classified as having srSLE varied widely depending on the definition used, from 2% to 27%.

The ten definitions most strongly linked to poor outcomes were then tested in machine-based prediction models.

One definition performed best: an SLE disease activity index score of 6 or more, a physician global assessment score above 1, a mild-to-moderate or severe flare, and glucocorticoid use of at least 10mg a day.

Associate Professor Kandane-Rathnayake said that if the definition was validated in other patient groups, it could help trials enrol patients at highest risk of poor outcomes, and improve consistency in future research and regulatory settings.