Darcy Ummels

Counting steps in activities of daily living in people with a chronic disease | 29 2 Table 2.3 Characteristics of the included population. Characteristics Participants (n=130) Gender, male, n (%) 55 (43.6) Age, years, mean (SD) 61.5 (11.1) Body mass index, kg/m 2 , mean (SD) 27.7 (5.2) Blood pressure, mm Hg, mean (SD) Systolic 136.2 (20.3) Diastolic 80.3 (9.7) Resting heart beat, beats per minute, mean (SD) 74.0 (12.2) Transcutaneous oxygen saturation, %, mean (SD) 96.4 (2.3) Diagnosed disease, n (%) Cardiovascular disease 20 (15.2) Chronic obstructive pulmonary disease 15 (11.4) Diabetes mellitus 8 (6.1) Cancer 15 (11.4) Osteoarthritis 18 (14.4) Chronic pain 19 (14.4) Combination 34 (27.3) Comorbidity, CIRS a 0 to 52, mean (SD) 6.2 (3.9) Average walk speed b (m/s) mean (SD) 1.3 0.3) Sufficient total activity, n (%) c 74 (56.4) Physical activity level (0 to 8), mean (SD) 3.8 (2.4) Physical activity with moderate intensity (0 to 4), mean (SD) 1.6 (1.6) Physical activity with vigorous intensity (0 to 4), mean (SD) 2.2 (1.5) a CIRS: Cumulative Illness Rating Score; b Based on the 10 ‐ meter walk test 44 ; c Based on the brief physical activity assessment tool and its accompanying cut ‐ off value. 43 Interobserver reliability The interobserver reliability of the gold standard, calculated in the random sample, was high (ICC agreement 0.98, P <0.001, 95% CI 0.96 to 0.99). There was no substantial offset (SEM agreement =81.6) and the Bland ‐ Altman plots showed no systematic differences between the observers (with narrow limits of agreement: –35.3 to 30.8 steps). Step count Step count for the gold standard and each tracker are shown in Table 2.4. The average total number of steps during the short and long activity protocols counted by the gold standard was 405.4 (SD 84.7). The average total number of steps for the short protocol was 327.7 (SD 54.3) and the average total number of steps for the long protocol was 446.6 (SD 58.6). There was no significant difference between the mean difference (gold standard versus activity tracker) in the short and long protocols. For all activity trackers except for the Activ8, the mean difference with the gold standard was lower than zero, which indicated an underestimation of the total number of steps. The mean difference