Tracing Gout Flares With Activity Trackers

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Wearable activity trackers are designed to monitor an individual's movement for fitness purposes, but researchers writing in Arthritis Research and Therapy describe its use in clinical research to examine the association between gout flares and the frequency of physical activity.

They found that, on average, the trackers measured 841 fewer daily steps that coincided with gout flares. This is important because gout flares "are a subjective and sometimes poorly captured outcome measure in gout research; hence, they are critical yet problematic as an endpoint in clinical trials. There is substantial interest in identifying methods to better define flares that are not dependent on direct patient report," wrote researchers who were led by Kenneth Saag, M.D., of the University of Alabama.

This was a pilot study that included gout patients who had hyperuricemia of at least 6.8 mg/dl and had at least two flares within the previous six months. The tracker used in this study, Fitbit Charge HR2, recorded physical activity, heart rate, and sleep data.

The study included 44 adults who were on average 49 years, 85% men, and 15% black. Most of the patients were on medication for gout (88% were on allopurinol or febuxostat) and 30% reported at least six flares in the last months. Only 33 of the 44 met the criteria for minimal wear time and flare reporting, with activity tracker data available for 60.5 percent of all total study days.

As previously reported by other studies on the same subject, this proof-of-concept study demonstrated objective evidence of reduced step counts when flares occurred. The activity trackers captured 204 (38%) person-weeks with flares and 340 (62%) person-weeks without flares. The mean daily step count was significantly lower (p < 0.0001) when gout flares occurred (5,900 steps plus or minus 4,071) as compared to when patients didn't experience flares (6,972 steps plus or minus 5,214). Of note, sleep did not differ.

Larger studies are needed to confirm the findings. " "If validated further, this could free patients from having to frequently answer questions and provide patient-reported outcome (PRO) data, or at least, reduce data collection burden often encountered by studies. Future work will be needed to assess the application of the passive data from wearable activity trackers to monitor gout flares while examining new interventions in gout, but these results are a promising first step to support the feasibility of incorporating these elements into such a study to better capture flares, especially using passive data sources alone, or infrequently supplemented by active data collection through PRO instruments," researchers wrote.

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REFERENCE

Elmagboul, N., Coburn, B.W., Foster, J. et al. Physical activity measured using wearable activity tracking devices associated with gout flares. Arthritis Res Ther 22, 181 (2020). https://doi.org/10.1186/s13075-020-02272-2