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Medicine Matters rheumatology

The rationale for this study was that patients with rheumatoid arthritis are at a two-fold greater risk for venous thromboembolisms than the general population. And the influence of biologic DMARD treatment, especially TNF inhibitors, is not well known, or even the results in the publications are conflicting. Recently, there was an observational study with patients with inflammatory bowel disease and they indicated-- the results indicated that TNF individuals may have a protective effect against VTEs.

To analyze our research questions, we took data from our German biologics register, RABBIT which is the prospective longitudinally-followed cohort of RA patients. And in this register, patients can be enrolled when they start b [biologic] DMARD treatment, either original or by similar or JAK inhibitor treatment, or when they start assist DMARD treatment after at least 20-month failure. So we included patients in this study that were enrolled between January 2009 to April 2019 in this work and had at least one follow up. And these were more than 11,000 patients.

In those patients, we analyzed the risk factors for VTEs and for that we used-- first we used-- we calculated crude incidence rate and then we used Cox regression with propensity score adjustment to adjust for the confounding indication, which occurs when you have those different treatment groups.

The main results from our study was first, an incidence rate of VTEs of 2.6 per 1,000 patient years and with a Cox regression, we found that higher age-- or age above 65 years-- and higher disease activity, which was measured by the CRP, that those factors are associated with an increased risk for VTEs. And better physical function as well as treatment was TNF inhibitors were associated with a significantly decreased risk.

For a rheumatologist, these results are important because on one hand, they show that TNF inhibitors are not associated with an increased risk for VTEs, which was suspected from some. And they also show what that it is very important to lower down the inflammatory level, so that the CRP levels are not as high anymore. And in addition, that patients that have a higher age of 65 years and above and lower capacity of physical function, that they have an increased risk for venous thromboembolism.

A strength of our analysis is that we are able to compare a lot of different treatments with several with different modes of action within one single cohort-- within one study design. And that is, I think, the greatest strength. And as well, we have the rheumatologist's report-- adverse events at regular time points, so we don't have to count on spontaneous reports. But we have we have the regular time points, regular assessments from the rheumatologist on adverse events and on treatment details.

The unanswered questions regarding VTE risk in RA patients is the risk conveyed by JAK inhibitors. This is something we couldn't analyze so far, because we don't have enough events on JAK inhibitors yet. You know that JAK inhibitors are not so long approved for the treatment of RA In Europe than in the USA and in other states. So at the moment, we are still accumulating observation in JAK inhibitors. And we hope with more person times on those treatments, we will also be able to analyze events of interest in those groups of treatments.