Ankylosing spondylitis patients with longstanding disease achieved significant improvements in both lumbar spine and hip bone mineral density (BMD) during 8 years of tumour necrosis factor-alpha (TNF-α) blocking therapy . The effect in the lumbar spine was most pronounced and main improvements occurred during the first 4 years of treatment.
Bone loss, which is reflected by low BMD, occurs quite frequently in patients suffering from ankylosing spondylitis. Interestingly, it can already be observed at early stages of the disease. Recent data showed that TNF-α blocking therapy has a beneficial effect on BMD with a 7.2% improvement in lumbar spine BMD and 2.2% improvement in hip BMD after 4 years of treatment with these agents .
Mark Siderius (University Medical Center Groningen; Medical Center Leeuwarden, the Netherlands) presented the results of a Dutch cohort study that assessed the effect of 8 years of TNF-α blocking therapy on the BMD of the lumbar spine and hip in ankylosing spondylitis patients. The 131 participants were 73% male, 83% HLA-B27+, and their mean age was 41.3 years. Patients had received TNF-α blocking therapy for at least 8 years, and the use of bisphosphonates at baseline or during follow-up was not permitted. At baseline, 34% and 19% of patients had low MD at the lumbar spine and hip. Median symptom duration was 14 years. During follow-up, 27% of patients switched to a second TNF-α inhibitor and disease activity improved significantly during treatment from mean ASDAS CRP 3.8 at baseline to 2.1 after 8 years.
The 8-year results showed that long-term TNF-α blocking therapy compared with baseline significantly improved BMD of the lumbar spine and hip BMD Z-scores at all follow-up visits. After 8 years, median percentage of improvement in absolute BMD TNF-α blocking therapy compared with baseline was 7.1% for the lumbar spine and 1.6% for the hip. Significant improvement compared with the previous time point at 4 years was found up to and including 4 years for the lumbar spine and up to and including 2 years for the hip, which explains flattening of improvement.
1. Siderius M, et al. The effect of 8 years of TNF-α blocking therapy on bone mineral density in patients with ankylosing spondylitis. Abstract THU0376. EULAR E-Congress, 3-6 June 2020.
2. Beek KJ, et al. Long‐Term Treatment With TNF‐Alpha Inhibitors Improves Bone Mineral Density But Not Vertebral Fracture Progression in Ankylosing Spondylitis. J Bone Miner Res. 2019;34(6):1041-1048.