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To investigate the coagulation system in gout patients and associations between disease activity and levels of coagulation markers.A prospective cohort study was performed with data from 30 Dutch gout patients. Levels of coagulation markers including APTT, PT, D-dimer, prothrombin F1 + 2, von Willebrand factor, and thrombin generation parameters were analyzed at baseline and 1-year visit. These markers were related to clinical markers of gout disease activity including the Gout Activity Score (GAS). Our hypothesis was that patients with gout and active disease have increased levels of coagulation markers and that a decrease in disease activity would lead to normalization of coagulation activity.A higher GAS was associated with increased levels of thrombin generation parameters including ETP (ß = 0.48, p = 0.01), peak thrombin (ß = 0.60, p = 0.001), and velocity index (ß = 0.57, p = 0.002). Tophaceous gout and higher SUA levels were associated with thrombin generation parameters. After 1 year, thrombin generation parameters showed a small procoagulant trend despite a moderate decrease in disease activity. Prospectively measured changes in disease activity according to the GAS were not associated with any of the coagulation markers.Patients with active gout have higher levels of thrombin generation markers, indicating a link between disease activity and coagulation. A change in disease activity after 1 year was not associated with significant changes in coagulation markers, probably due to prolonged low-grade inflammation. Future studies should focus on levels of coagulation markers in comparison with the general population and the effect of adequate gout treatment. Key Points • Patients with gout have an increased risk of cardiovascular events. • High disease activity was associated with higher levels of thrombin generation markers. • Over time, small decreases in inflammation were associated with a decrease in D-dimer and thrombin generation.

The objective of this study was to evaluate whether self-reported knee instability is associated with activity limitations in patients with knee osteoarthritis (OA), in addition to knee pain and muscle strength. A cohort of 248 patients diagnosed with knee OA was examined. Self-reported knee instability was defined as the perception of any episode of buckling, shifting, or giving way of the knee in the past 3 months. Knee pain was assessed using a numeric rating scale, and knee extensor and flexor strength were measured using an isokinetic dynamometer. Activity limitations were measured by using the Western Ontario and McMasters Universities Osteoarthritis Index physical function questionnaire, the timed Get Up and Go, and the timed stair climbing and three questionnaires evaluating walking, climbing stairs, and rising from a chair. Other potential determinants of activity limitations were also collected, including joint proprioception, joint laxity, age, sex, body mass index (BMI), disease duration, and radiographic disease severity. Regression analyses evaluated the effect of adding self-reported knee instability to knee pain and muscle strength, when examining associations with the activity limitations measures. Self-reported knee instability was common (65 %) in this cohort of patients with knee OA. Analyses revealed that self-reported knee instability is significantly associated with activity limitations, even after controlling for knee pain and muscle strength. Joint proprioception, joint laxity, age, sex, BMI, duration of complaints, and radiographic severity did not confound the associations. In conclusion, self-reported knee instability is associated with activity limitations in patients with knee OA, in addition to knee pain and muscle strength. Clinically, self-reported knee instability should be assessed in addition to knee pain and muscle strength.