Factors associated with oral glucocorticoid use in patients with rheumatoid arthritis: a drug use study from a prospective national biologics registry

BACKGROUND: Glucocorticoids (GCs) are used in ~ 60% of patients with rheumatoid arthritis (RA). Although disease-modifying, they also have significant adverse effects. Understanding factors associated with GC use may help minimise exposure. The aims of the present study were to describe oral GC use in RA; determine any change in use over time; and determine factors associated with oral GC use, commencement or cessation. METHODS: Adult patients with RA were identified in the Australian Rheumatology Association Database (ARAD), a national Australian registry that collects long-term outcome data from patients with inflammatory arthritis. Patients were categorised by their ARAD date of entry (DOE), with population-averaged logistic regression and transition state analysis used to determine any change in GC use over time. Fixed-effects panel regression was used to examine whether GC current use was associated with pain/arthritis activity/Health Assessment Questionnaire (HAQ) scores or medication use. Transition state analysis was used to assess whether these factors influenced the commencement or cessation of GCs. RESULTS: A total of 3699 patients with RA completed a baseline ARAD questionnaire (73% female, mean age 57 years). The probability of GC use decreased over time according to ARAD DOE: September 2001 to March 2005, 55% (95% CI 52-58%); March 2005 to September 2008, 47% (45-49%); September 2008 to March 2012, 42% (39-45%); and March 2012 to October 2015, 39% (34-43%) (p < 0.001). Conventional synthetic disease-modifying anti-rheumatic drugs (OR 10.13; 95% CI 8.22-12.47), non-steroidal anti-inflammatory drugs (1.18; 1.02-1.37) and opioids (2.14; 1.84-2.48) were associated with GC current use, as were lower pain scores (0.94; 0.90-0.98), higher arthritis activity scores (1.09; 1.05-1.14) and poorer HAQ scores (1.52; 1.30-1.79). Use of biologic disease-modifying anti-rheumatic drugs (bDMARDs) was not associated with GC current use (0.98; 0.83-1.15) or GC cessation (HR 0.87; 95% CI 0.75-1.01), but it was associated with GC commencement (0.54; 0.47-0.62). CONCLUSIONS: The probability of oral GC use decreased over time, with reduced commencement and increased cessation of GCs. The modest effect of bDMARDs on GC cessation was not statistically significant.