Introduction: Obtaining body weights remotely could improve feasibility of pragmatic trials. This investigation examined whether weights collected via cellular scale or electronic health record (EHR) correspond to gold standard in-person study weights.
Methods: The agreement of paired weight measurements from cellular scales were compared to study scales from a weight loss intervention and EHR-collected weights were compared to study scales from a weight loss maintenance intervention. Differential weight change estimates between intervention and control groups using both pragmatic methods were compared to study collected weight. In the Log2Lose feasibility weight loss trial, in-person weights were collected bi-weekly and compared to weights collected via cellular scales throughout the study period. In the MAINTAIN weight loss maintenance trial, in-person weights were collected at baseline, 14, 26, 42 and 56 weeks. All available weights from the EHR during the study period were obtained.
Results: On average, in Log2Lose cellular scale weights were 0.6 kg (95% CI: -2.9, 2.2) lower than in-person weights; in MAINTAIN, EHR weights were 2.8 kg (SE: -0.5, 6.0) higher than in-person weights. Estimated weight change using pragmatic methods and study scales in both studies were in the same direction and of similar magnitude.
Conclusion: Both methods can be used as cost-effective and real-world surrogates within a tolerable variability for the gold-standard.
Trial registration: NCT02691260; NCT01357551.
Keywords: body weight; research methods; weight change.
© 2023 The Authors. Obesity Science & Practice published by World Obesity and The Obesity Society and John Wiley & Sons Ltd.