Wearable technology has become increasingly popular in monitoring health metrics, particularly in managing chronic conditions such as cardiovascular disease. This validation study, published in JMIR Cardio, evaluates the accuracy of a consumer-grade wrist-worn activity tracker, specifically the Fitbit Inspire 3, in measuring sedentary behavior among older outpatients with cardiac issues.
Study Overview
The objective of this study was to assess the agreement between sedentary time measured by the Fitbit Inspire 3 and a research-grade waist-worn accelerometer, the ActiveStyle Pro HJA-750C, in a cohort of Japanese outpatients with heart failure and ischemic heart disease. A total of 51 participants, with a mean age of 78.4 years, wore both devices simultaneously for a week, allowing researchers to compare the data collected.
Key Findings
The results indicated that the mean sedentary time recorded by the waist-worn accelerometer was 497.9 minutes, while the Fitbit recorded a higher mean of 559.9 minutes. The correlation between the two devices was strong (r=0.905), suggesting that the Fitbit can reliably track sedentary behavior. However, the Fitbit overestimated sedentary time by approximately 62 minutes, indicating a fixed bias but no proportional bias.
After applying a constant bias correction, the concordance correlation coefficient (CCC) improved significantly, indicating that the adjusted Fitbit readings were more closely aligned with the research-grade device. The study also noted that no demographic factors, such as age or sex, significantly influenced the bias in measurements.
Implications for Use
These findings suggest that while consumer-grade wearables like the Fitbit Inspire 3 can provide useful data for monitoring sedentary behavior in older adults with cardiovascular conditions, the inherent bias must be accounted for. The study advocates for the calibrated use of such devices in clinical settings, particularly for scalable monitoring in ambulatory cardiac care.
What this study does not show
While the study demonstrates the potential for consumer-grade trackers to monitor sedentary behavior, it does not establish the effectiveness of these devices in improving health outcomes or behavior change in patients with cardiovascular disease.
Evidence scorecard
- Analytic validity: Established
- Clinical validity: Established
- Clinical utility: Not established
The evidence is based on a validation study involving human participants.