Assessment of physical activity in out-of-hospital cardiac arrest survivors: a sub-study of the targeted hypothermia versus targeted normothermia after out-of-hospital cardiac arrest (TTM2) trial

Abstract Funding Acknowledgements Type of funding sources: Foundation. Main funding source(s): Riksförbundet HjärtLung Hans-Gabriel and Alice Trolle-Wachtmeister Foundation for Medical Research. Background Low physical activity is a risk factor for new cardiac events in out-of-hospital cardiac arrest (OHCA) survivors. Physical activity could be assessed by both self-reports and objective accelerometer data. Aim To investigate the coherence between self-reported and objectively assessed physical activity among OHCA survivors. 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. Additionally, moderate- and vigorous-intensity physical activity were objectively assessed with an accelerometer (ActiGraph wGT3X BT) worn at the waist for seven consecutive days. Results 49 of 106 included OHCA survivors had answered the two questions and had seven valid days of accelerometer assessment and were included in the analyses. According to self-reports, the median of moderate-intensity physically active days was 5 [3:7] and vigorous-intensity physically active days was 1 [0:3] during the week wearing the accelerometer. Assessed by accelerometery, the median of moderate-intensity physically active days was 3 [1:5] and vigorous-intensity physically active days was 0 [0:0] . Correlations between self-reported and objectively assessed moderate- and vigorous-intensity physical activity were sufficient (rs=.336, p=0.018) and (rs=.375, p=0.008) and agreements were fair (k=0.269, p=0.001) and slight (k=0.148, p=0.015). Conclusion Self-reported and objectively assessed moderate- and vigorous-intensity physical activity correlated but the agreements were only slight to fair indicating that researchers need to exert caution when interpreting results from physical activity questionnaires.