MELBOURNE – Adding a patient’s current dose of glucocorticoids as a new metric in the systemic lupus erythematosus disease activity index score could make it a better predictor of damage accrual, Dafna Gladman, MD, told an international congress on systemic lupus erythematosus.
Dr. Gladman and her colleagues from the University of Toronto Lupus Clinic at Toronto Western Hospital conducted a three-part study that aimed to incorporate glucocorticoid dose into the existing systemic lupus erythematosus disease activity index (SLEDAI)-2K score.
“SLEDAI-2K is one of the most commonly used disease activity measures in lupus, both in clinical practice and research, but this index, as we all know, does not account for severity within an organ system,” Dr. Gladman told the conference.“In clinical trials, the use of standard of care, which includes the use of corticosteroids, often confounds the results, and we see that in a number of trials, so there has been an unmet need to develop an index that incorporates the glucocorticoid dose into a disease activity measure.”
The first part of the study involved identification of 131 patient scenarios from a longitudinal cohort followed at the clinic for 20 years that included eight categories based on glucocorticoid dose, ranging from 5 to 60 mg/day.
In the second phase, three rheumatologists ranked the disease activity for each patient scenario using the Physician Global Assessment, and the study team used these rankings to derive a formula to explain the association between SLEDAI and glucocorticoid category.
The third phase used data from an inception cohort of patients from the clinic with 10 years of follow-up to validate the new score – called SLEDAI-2KG – by predicting the accrual of damage over the course of follow-up.
Researchers found that the modified score was significantly better at predicting damage accrual than was the original score.
“If somebody may have a very low disease activity measurable by the instrument, SLEDAI, but they’re still taking 10-15 mg prednisone, we need to somehow take it into account,” Dr. Gladman said in an interview. “It tells you that thinking that the patient is doing well but still taking 15 mg of prednisone is not appropriate.”
Session cochair Mandana Nikpour, MBBS, PhD, of St. Vincent’s Hospital and the University of Melbourne, questioned whether incorporating a treatment into a score for disease activity was too circular.
However, Dr. Gladman stressed that the glucocorticoid score was not based on what the physician planned to do, but what the patient was taking at the time of the consultation.
“If a patient has a rash and is currently taking 40 mg of prednisone, the value of the SLEDAI would be increased because of that dose,” she said. “On the other hand, somebody might come in with pleurisy, and some people might treat that with 60 mg, but they are only taking 20 mg; that suggests that the value would be lower in that particular patient.”
The study was supported by GlaxoSmithKline. Dr. Gladman and two coauthors declared receiving funding from GlaxoSmithKline.