Simulation model to assess the validity of the clinical portfolio diet score used in the PortfolioDiet.app for dietary self-tracking: a secondary analysis of a randomized controlled trial in hyperlipidemic adults

Meaghan E Kavanagh; Andrea J Glenn; Laura Chiavaroli; Gloria A Morgan; Robert G Josse; Vasanti S Malik; Christopher P F Marinangeli; Cyril W C Kendall; David J A Jenkins; John L Sievenpiper

doi:10.3389/fnut.2024.1398450

Simulation model to assess the validity of the clinical portfolio diet score used in the PortfolioDiet.app for dietary self-tracking: a secondary analysis of a randomized controlled trial in hyperlipidemic adults

Front Nutr. 2024 Aug 7:11:1398450. doi: 10.3389/fnut.2024.1398450. eCollection 2024.

Authors

Meaghan E Kavanagh^{1

2}, Andrea J Glenn^{1

2

3}, Laura Chiavaroli^{1

2

4}, Gloria A Morgan², Robert G Josse^{1

2

4

5

6}, Vasanti S Malik^{1

3}, Christopher P F Marinangeli⁷, Cyril W C Kendall^{1

2

8}, David J A Jenkins^{1

2

4

5

6}, John L Sievenpiper^{1

2

4

5

6}

Affiliations

¹ Department of Nutritional Sciences, Temerty Faculty of Medicine, University of Toronto, Toronto, ON, Canada.
² Toronto 3D Knowledge Synthesis and Clinical Trials Unit, Clinical Nutrition and Risk Factor Modification Center, St. Michael's Hospital, Toronto, ON, Canada.
³ Department of Nutrition, Harvard T.H. Chan School of Public Health, Boston, MA, United States.
⁴ Li Ka Shing Knowledge Institute, St. Michael's Hospital, Toronto, ON, Canada.
⁵ Division of Endocrinology and Metabolism, St. Michael's Hospital, Toronto, ON, Canada.
⁶ Department of Medicine, Temerty Faculty of Medicine, University of Toronto, Toronto, ON, Canada.
⁷ Protein Industries Canada, Regina, SK, Canada.
⁸ College of Pharmacy and Nutrition, University of Saskatchewan, Saskatoon, SK, Canada.

Abstract

Introduction: The Portfolio Diet combines cholesterol-lowering plant foods for the management of cardiovascular disease risk. However, the translation of this dietary approach into clinical practice necessitates a user-friendly method for patients to autonomously monitor their adherence.

Objective: This study aimed to develop and validate the clinical-Portfolio Diet Score (c-PDS) as a food-based metric to facilitate self-tracking of the Portfolio Diet.

Methods: Using a simulation model to estimate the c-PDS, the validity was assessed in a secondary analysis of a completed trial of the Portfolio Diet in 98 participants with hyperlipidemia over 6 months. Concurrent and predictive validity of the estimated c-PDS were assessed against the reference measure (weighed 7-day diet records) and concomitant changes in LDL-C from baseline to 6 months. Bland-Altman analysis was used to assess the limits of agreement between the two methods.

Results: The c-PDS was positively correlated with dietary adherence as measured using the 7-day diet records (r = 0.94, p < 0.001). The c-PDS was negatively correlated with change in LDL-C (r = -0.43, p < 0.001) with a 1-point increase in the c-PDS being associated with a - 0.04 mmol/L (CI:-0.06,-0.03; p < 0.001) or a 1.09% reduction in LDL-C. Visual evaluation of the Bland-Altman plots showed reasonable agreement.

Conclusion: These findings indicate good validity of the c-PDS for primary prevention in adults with hyperlipidemia. The predictive validity findings have informed the goals and messaging within the PortfolioDiet.app, a digital health application for delivering the Portfolio Diet. Future research will assess the effectiveness of the intended combination of the c-PDS and the PortfolioDiet.app in supporting behavior change.

Keywords: cholesterol reduction; dietary patterns; lipids; nutrition; portfolio diet; self-monitoring.

Grants and funding

The author(s) declare that financial support was received for the research, authorship, and/or publication of this article. This research was funded by the Canadian Institutes of Health Research (CIHR) Doctoral Research Award: FRN: 181403. The Diet, Digestive tract, and Disease (3D) Centre, funded through the Canada Foundation for Innovation and the Ministry of Research and Innovation’s Ontario Research Fund, provided the infrastructure for the conduct of this work. MK was supported by the Canadian Institutes of Health Research (CIHR) Doctoral Research Award: FRN: 181403 and a Toronto 3D Knowledge Synthesis and Clinical Trials foundation PhD Scholarship Award. AG was supported by a Canadian Institute of Health Research Fellowship. LC was funded by a Toronto 3D New Investigator Award. DJ was funded by the Government of Canada through the Canada Research Chair Endowment. JS was funded by a PSI Graham Farquharson Knowledge Translation Fellowship; Canadian Diabetes Association Clinician Scientist Award; Canadian Institute of Health Research INMD and CNS New Investigator Partnership Prize; and Banting & Best Diabetes Centre Sun Life Financial New Investigator Award.