TNF-α inhibitors improve bone mineral density in AS patients

Ankylosing spondylitis (AS) patients with longstanding disease achieved significant improvements in both lumbar spine and hip bone mineral density (BMD) during 8 years of tumour necrosis factor (TNF)α blocking therapy [1]. Most pronounced was the effect in the lumbar spine and main improvements occurred during the first 4 years of treatment.

Bone loss, reflected by low BMD, occurs frequently in patients suffering from AS. Interestingly, it can already be observed at the early stages of the disease. Recent data showed that TNFα blocking therapy has a beneficial effect on BMD, with a 7.2% improvement in lumbar spine BMD and a 2.2% improvement in hip BMD after 4 years of treatment with these agents [2]. Researchers from the Netherlands assessed the effect of 8 years of TNFα blocking therapy on the BMD of the lumbar spine and hip in AS patients. The results of this study were presented by Mark Siderius (University Medical Center Groningen; Medical Center Leeuwarden, the Netherlands).

Of the 131 AS patients included in the study, 73% were male, 83% HLA-B27+, and the mean age was 41.3 years. Patients had received TNFα blocking therapy for at least 8 years, and the use of bisphosphonates at baseline or during follow-up was not permitted. Median symptom duration was 14 years.

During follow-up, which took place at baseline, 1 year, 2 years, and then bi-annually, 27% of patients switched to a second TNFα inhibitor, and disease activity improved significantly during treatment from mean Ankylosing Spondylitis Disease Activity Score (ASDAS)-C-reactive protein (CRP) 3.8 at baseline to 2.1 after 8 years. With regard to BMD, 34% and 19% of patients had low lumbar spine and hip BMD, respectively, at baseline. The BMD of the lumbar spine and hip BMD Z-scores significantly improved during TNFα blocking therapy at all follow-up visits compared to baseline. Significant improvement compared with the previous timepoint was found in the first year, and scores continued to improve up to 4 years of treatment for the lumbar spine and up to 2 years for the hip. Median percentage of improvement in absolute BMD after 8 years of TNFα blocking therapy compared with baseline was 7.1% for the lumbar spine and 1.6% for the hip (see Figure).

Figure: Bone mineral density improvement in lumbar spine (A) and hip (B) [1]



BMD, bone mineral density; LS, lumbar spine. Box-and-whisker plot: Boxes indicate medians with interquartile ranges; + indicates mean; whiskers indicate 1.5 times interquartile distances; * indicate outliers.

1. Siderius M, et al. Abstract THU0376. EULAR E-Congress, 3-6 June 2020.
2. Beek KJ, et al. J Bone Miner Res. 2019;34(6):1041-1048.

Posted on 14 August 202017 May 2024