A large population-based study found no evidence that treatment with biological DMARDs reduces fracture risk in patients with rheumatoid arthritis (RA).

Ingebjørg Tronstad, PhD candidate

Compared with the general population, patients with RA have reduced bone mineral density and increased fracture risk. Although bone-sparing properties for biological disease-modifying antirheumatic drugs (DMARDs) have been demonstrated, the effect of different types of DMARDs on reducing fracture risk is yet to be explored in detail.

To answer this question, Ingebjørg Tronstad, PhD candidate, and colleagues conducted the Trondelag Health Study (HUNT), a population-based longitudinal study, the results of which were shared at EULAR 2023, held May 31 to June 3, in Italy. HUNT included 96,354 participants who were classified based on RA status according to existing patient records or International Classification of Disease codes (ICD9 and 10) and the American College of Rheumatology/European League Against Rheumatism criteria. Disease status was registered at baseline and updated if RA was diagnosed later. Accordingly, 1,033 patients had RA (mean age, 46.3 years, 53% women), and 95,321 did not. Of the patients with RA, 401 were diagnosed before inclusion in the study and 632 during follow-up.

Major osteoporotic fractures (MOFs) and use of DMARDS were also recorded. Tronstad classified patients into three groups: 57 patients who had never used DMARDs (never DMARDs), 727 patients using conventional synthetic (cs) DMARDs only, and 230 patients who had never used biological (b) DMARDs. Participants were followed until the first MOF, death, emigration, or end of follow-up in October 2021.

Tronstad revealed that patients with RA, regardless of treatment, had an almost 50% increased risk of MOF compared with patients without RA (HR, 1.44; 95% CI, 1.25-1.65). The incidence rates of MOF per 1,000 person-years were higher in RA overall and in all DMARD treatment groups compared with patients without RA. After Cox regression analyses adjusted for age, sex, and smoking status, it was found that across the three treatment groups, the never-DMARDs group had the highest risk of MOF (HR, 2.05; 95% CI, 1.28-3.31) followed by the csDMARDs-group (HR, 1.5; 95% CI, 1.29-1.75). In contrast, treatment with bDMARDs did not significantly correlate with MOFs (HR, 1.03; 95% CI, 0.70-1.50).

The investigators concluded that although RA is associated with MOFs, it is encouraging that individuals treated with bDMARDS had no association with MOFs, which should be considered in future treatment regimens for RA patients.

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