Risk of Serious Infection With Low-dose Glucocorticoids in Patients With Rheumatoid Arthritis: An Instrumental...

Area of Science:

• Rheumatology
• Infectious Disease Epidemiology
• Pharmacovigilance

Background:

• Low-dose glucocorticoids are frequently prescribed for rheumatoid arthritis (RA).
• Previous observational studies suggest an elevated risk of serious infections with low-dose glucocorticoid use.
• Concerns regarding residual confounding in prior studies persist.

Purpose of the Study:

• To investigate the association between low-dose glucocorticoid use and the risk of serious infection in RA patients.
• To address potential confounding by using an instrumental variable (IV) approach.

Main Methods:

• Adult RA patients on stable immunomodulatory therapy without glucocorticoids or receiving ≤5 mg/day were identified from Medicare data (2006-2015).
• Provider preference for glucocorticoids was used as an instrumental variable (IV).
• Cause-specific proportional hazards models assessed the association between low-dose glucocorticoid use and infection requiring hospitalization.

Main Results:

• The study included 163,603 treatment episodes from 120,656 patients.
• Rheumatologist's preference for glucocorticoids was strongly associated with their prescription (OR 1.81).
• Instrumental variable analysis revealed an increased risk of infection requiring hospitalization with low-dose glucocorticoid use (HR 1.26), consistent with multivariable analysis (HR 1.24).

Conclusions:

• Instrumental variable analysis indicates that low-dose glucocorticoids are associated with an increased risk of hospitalization due to infection in RA patients on stable immunomodulatory therapy.
• The findings align with traditional analysis, reinforcing the link between low-dose glucocorticoid use and infection risk.