Measuring change in trials of physical activity interventions: A comparison of self-report questionnaire and accelerometry within the PACE-UP trial 11 Medical and Health Sciences 1117 Public Health and Health Services

Citation

Limb ES, Ahmad S, Cook DG, Kerry SM, Ekelund U, Whincup PH, Victor CR, Iliffe S, Ussher M, Fox-Rushby J, Furness C, Ibison J, Dewilde S & Harris T (2019) Measuring change in trials of physical activity interventions: A comparison of self-report questionnaire and accelerometry within the PACE-UP trial 11 Medical and Health Sciences 1117 Public Health and Health Services. International Journal of Behavioral Nutrition and Physical Activity, 16 (1), Art. No.: 10. https://doi.org/10.1186/s12966-018-0762-5

Abstract
Background: Few trials have compared estimates of change in physical activity (PA) levels using self-reported and objective PA measures when evaluating trial outcomes. The PACE-UP trial offered the opportunity to assess this, using the self-administered International Physical Activity Questionnaire (IPAQ) and waist-worn accelerometry. Methods: The PACE-UP trial (N = 1023) compared usual care (n = 338) with two pedometer-based walking interventions, by post (n = 339) or with nurse support (n = 346). Participants wore an accelerometer at baseline and 12 months and completed IPAQ for the same 7-day periods. Main outcomes were weekly minutes, all in ≥10 min bouts as per UK PA guidelines of: i) accelerometer moderate-to-vigorous PA (Acc-MVPA) ii) IPAQ moderate+vigorous PA (IPAQ-MVPA) and iii) IPAQ walking (IPAQ-Walk). For each outcome, 12 month values were regressed on baseline to estimate change. Results: Analyses were restricted to 655 (64%) participants who provided data on all outcomes at baseline and 12 months. Both intervention groups significantly increased their accelerometry MVPA minutes/week compared with control: postal group 42 (95% CI 22, 61), nurse group 43 (95% CI 24, 63). IPAQ-Walk minutes/week also increased: postal 57 (95% CI 2, 112), nurse 43 (95% CI -11, 97) but IPAQ-MVPA minutes/week showed non-significant decreases: postal -11 (95% CI -65, 42), nurse -34 (95% CI -87, 19). Conclusions: Our results demonstrate the necessity of using a questionnaire focussing on the activities being altered, as with IPAQ-Walk questions. Even then, the change in PA was estimated with far less precision than with accelerometry. Accelerometry is preferred to self-report measurement, minimising bias and improving precision when assessing effects of a walking intervention. © 2019 The Author(s).

Keywords
accelerometry; adult; aged; Article; clinical effectiveness; comparative study; controlled study; female; human; international physical activity questionnaire; male; nurse; nursing care; parallel design; patient care; randomized controlled trial; self report; treatment outcome; walking; actimetry; exercise; health promotion; middle aged; outcome assessment; procedures; questionnaire; walking, Accelerometry; Actigraphy; Aged; Exercise; Female; Health Promotion; Humans; Male; Middle Aged; Outcome Assessment (Health Care); Self Report; Surveys and Questionnaires; Walking

Journal
International Journal of Behavioral Nutrition and Physical Activity: Volume 16, Issue 1