Agreement between self-reported and objectively assessed physical activity among out-of-hospital cardiac arrest survivors

Background

Low level of physical activity is a risk factor for new cardiac events in out-of-hospital cardiac arrest (OHCA) survivors. Physical activity can be assessed by self-reporting or objectively by accelerometery.

Aim

To investigate the agreement between self-reported and objectively assessed physical activity among OHCA survivors

Hypothesis

Self-reported levels of physical activity will show moderate agreement with objectively assessed levels of physical activity.

Method

Cross-sectional study including OHCA survivors in Sweden, Denmark, and the United Kingdom. Two questions about moderate and vigorous intensity physical activity during the last week were used as self-reports. Moderate and vigorous intensity physical activity were objectively assessed with accelerometers (ActiGraph GT3X-BT) worn upon the right hip for 7 consecutive days.

Results

Forty-nine of 106 OHCA survivors answered the two questions for self-reporting and had 7 valid days of accelerometer assessment. More physically active days were registered by self-report compared with accelerometery for both moderate intensity (median 5 [3:7] vs. 3 [0:5] days; p < 0.001) and vigorous intensity (1 [0:3] vs. 0 [0:0] days; p < 0.001). Correlations between self-reported and accelerometer assessed physical activity were sufficient (moderate intensity: r_s = 0.336, p = 0.018; vigorous intensity: r_s = 0.375, p = 0.008), and agreements were fair and none to slight (moderate intensity: k = 0.269, p = 0.001; vigorous intensity: k = 0.148, p = 0.015). The categorization of self-reported versus objectively assessed physical activity showed that 26% versus 65% had a low level of physical activity.

Conclusion

OHCA survivors reported more physically active days compared with the results of the accelerometer assessment and correlated sufficiently and agreed fairly and none to slightly.