Balancing data quality and participant burden: A comparative analysis of abbreviated vs extended symptom diaries in the CanTreatCOVID trial
et al., medRxiv, doi:10.64898/2026.01.23.26343617, Jan 2026
Secondary analysis of the CanTreatCOVID paxlovid RCT comparing adherence and symptom reporting between a 9-item abbreviated diary and 34-item FLU-PRO Plus diary in 712 COVID-19 outpatients, showing no significant difference in compliance, with low compliance in both groups (68.1% vs 64.4%). Predictive models for recovery showed only marginal gains from the extended 34-item format. Authors conclude that abbreviated symptom diaries provide comparable data quality while potentially reducing participant burden.
Patients in the treatment group were significantly more likely to report data in this open-label trial, and the analysis provides information on the potential impact of missing data in these kind of trials.
Patients with severe symptoms and worse self-reported health were more likely to not report data. Combined with the group differential where control patients were more likely to not report data, this means that efficacy may be underestimated when not accounting for missing data (since more of the more severe control patients are missing).
Authors have released this secondary analysis but have not released the results of the study for the efficacy of paxlovid.
Hosseini et al., 28 Jan 2026, Randomized Controlled Trial, Canada, preprint, 15 authors.
Contact: andrew.pinto@utoronto.ca.
Balancing data quality and participant burden: A comparative analysis of abbreviated vs extended symptom diaries in the CanTreatCOVID trial
doi:10.64898/2026.01.23.26343617
Background: Symptom diaries are widely used in acute respiratory infection trials to capture patientreported symptom severity and recovery. Longer questionnaires may provide a more complete clinical picture but can increase participant burden and reduce adherence. Evidence directly comparing long and short formats within the same trial is limited. Objective: To compare adherence, symptom trajectories, agreement between recovery measures, and predictive performance for recovery-related outcomes between a short and long symptom diary in an outpatient SARS-CoV-2 trial Methods: This secondary analysis of the CanTreatCOVID trial compared a 9-item Abbreviated Diary and a 34-item FLU-PRO Plus Diary over 14 days in non-hospitalized participants with confirmed SARS-CoV-2 infection. Outcomes included diary initiation, completion, completion rate, compliance, symptom trajectories, agreement between recovery outcomes, and predictive performance. Analyses used logistic regression, generalized estimating equations, survival models, and predictive modelling.
References
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DOI record:
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"DOI": "10.64898/2026.01.23.26343617",
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"abstract": "<jats:p>Background: Symptom diaries are widely used in acute respiratory infection trials to capture patient-reported symptom severity and recovery. Longer questionnaires may provide a more complete clinical picture but can increase participant burden and reduce adherence. Evidence directly comparing long and short formats within the same trial is limited. \n\nObjective: To compare adherence, symptom trajectories, agreement between recovery measures, and predictive performance for recovery-related outcomes between a short and long symptom diary in an outpatient SARS-CoV-2 trial.\n\nMethods: This secondary analysis of the CanTreatCOVID trial compared a 9-item Abbreviated Diary and a 34-item FLU-PRO Plus Diary over 14 days in non-hospitalized participants with confirmed SARS-CoV-2 infection. Outcomes included diary initiation, completion, completion rate, compliance, symptom trajectories, agreement between recovery outcomes, and predictive performance. Analyses used logistic regression, generalized estimating equations, survival models, and predictive modelling. \n\nResults: Of 712 participants, 638 used the Abbreviated Diary and 74 the FLU-PRO Plus Diary. Baseline characteristics were similar between groups. Diary type was not significantly associated with diary initiation or full 14-day compliance, whereas treatment assignment was associated with higher adherence (p < 0.0001). Completion rates were slightly higher in the Abbreviated group (68.1% vs. 64.4%), but differences were not statistically significant. Agreement between \"feeling recovered\" and \"return to usual health\" was strong to excellent (κ = 0.8371-0.8859), while agreement with \"return to usual activities\" was moderate (κ = 0.5273-0.6583). Predictive models performed well for both diaries (AUCs 0.87-0.94), with only marginal gains from including the extended FLU-PRO Plus items. \n\nConclusion: In this outpatient SARS-CoV-2 trial, abbreviated and extended symptom diaries produced comparable adherence, symptom trajectories, and predictive performance. Future research should extend follow-up beyond 14 days to capture longer-term patterns and test diary performance in more diverse and digitally underserved populations.</jats:p>",
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