TNFi, IL-17i reduce risk of osteoporosis, but not hip fracture, in r-axSpA patients

Patients with radiographic axial spondyloarthritis (r-axSpA) who have been exposed to tumour necrosis factor inhibitor (TNFi) and interleukin (IL)-17 inhibitor (IL-17i) appear to have a lower risk of osteoporosis, but not hip fracture, than biologic disease-modifying antirheumatic drug (bDMARD)-naïve individuals, a recent study has shown.

“Exposure to TNFi, but not IL-17i, may be associated with a lower risk of vertebral fracture compared with the bDMARD-naïve group,” the authors said.

A total of 37,708 patients with r-axSpA were included in this national cohort study. The outcomes assessed included osteoporosis, vertebral fracture, and hip fracture.

The authors used multivariable time-varying Cox regression models to examine the comparative risk of each outcome in the following groups: TNFi vs bDMARD-naïve, IL-17i vs bDMARD-naïve, and IL-17i vs TNFi. In comparing TNFi with IL-17i, the line of bDMARD treatment was matched between the two groups at a 4:1 ratio.

Exposure to TNFi (adjusted hazard ratio [aHR], 0.83, 95 percent confidence interval [CI], 0.76‒0.90; p<0.01) and IL-17i (aHR, 0.19, 95 percent CI, 0.10‒0.38; p<0.01) correlated with a reduced risk of osteoporosis compared with the bDMARD-naïve group. IL-17i (aHR, 0.23, 95 percent CI, 0.11‒0.46; p<0.001) also correlated with a lower risk of osteoporosis than TNFi.

Compared with the bDMARD-naïve group, TNFi-treated patients exhibited a reduced risk of vertebral fracture (aHR, 0.64, 95 percent CI, 0.59‒0.70; p<0.01). Patients exposed to IL-17i also showed a lower risk of vertebral fracture, but this did not reach statistical significance (aHR, 0.52, 95 percent CI, 0.25‒1.09; p=0.09).

No difference in hip fracture risk was observed across treatment groups.