Cohort Comparison: Wearable Measures of ILI Burden and TTRB in Participants With Confirmed Influenza Infection Compared With Those Reporting ILI Symptoms Only
symptoms-only, infection, ILI
REGRESSION, INFECTION, INFLUENZA-LIKE ILLNESS, INFLUENZA
Demographics and baseline characteristics were similar between participants with confirmed influenza infection during the study (influenza-positive cohort) and those with ILI symptoms only (symptoms-only cohort; Table S4 in Daily influenza-like illness (ILI) burden and time to return to baseline (TTRB) in the participants with confirmed influenza infection versus those with ILI symptoms only. Colored data (plot points, lines, and boxes) represent the participants who were influenza positive (influenza+); gray lines indicate those with ILI symptoms only. (A) Results of regression analyses of day-by-day ILI burdens of influenza+ and ILI symptoms–only cohorts are shown; separate regression analyses were conducted for each wearable sensor feature. Plotted points are model-fitted estimates (95% CI error bars) for each cohort, on each day of the ILI window and for the baseline period (computed as the mean across all healthy days; represented by b on the x-axis). Diamonds above the x-axis indicate contrasts reaching statistical significance after Bonferroni correction for 14 tests; contrasts were the difference in ILI burden between day n and baseline for the influenza+ cohort compared with the ILI symptoms–only cohort. (B) TTRB and cumulative ILI burden for each sensor feature are shown for individual participants (cloud plots) and overall (density distributions) for influenza+ and ILI symptoms–only cohorts. For TTRB (first 2 columns), box plots (center line, median; box limits, upper and lower quartiles; points, outliers) are overlaid and annotated with the median value for the corresponding population. For cumulative ILI burden (third column), the mean and 95% CI (point with error bars) are overlaid and annotated with the mean value. bpm: beats per minute; influenza+: influenza-positive; RHR: resting heart rate; RHR δ: the change in RHR from the previous day; spm: steps per minute.Participants who tested positive for influenza also exhibited a longer TTRB for wearable sensor features compared with the ILI symptoms–only cohort; the TTRB was 3 days longer for total daily steps (