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T 04: Missing ePRO Data: Impacts on Clinical Trial Results

Poster Presenter

      Elisa Holzbaur

      • Manager, ePRO Services
      • Almac Group
        United States


This poster will first review and evaluate the impacts of risks associated with missing PRO data to clinical trials, and then will identify and assess mitigation strategies to prevent missing data.



Literature review was conducted on the analysis and interpretation of PRO measure results. Also, data from a global web-based survey (2013) on patients who participated in at least 1 clinical trial requiring PRO entry recording was analyzed for non-compliance and patient reasons for non-compliance.


Results of the literature review indicate that data quality and completeness is important to clinical trial results, in particular when it is being used to support primary and secondary endpoints. As PRO data are frequently used to support primary and secondary trial endpoints, the impacts of missing PRO data on trials may be significant. Overall project risk is low when compliance rates are high (e.g., 90-100%). As compliance rates drop to <80%, the bias introduced in the results increases, the quality of the data decreases, and the risks for the data not being able to be used in the analysis rises. The types of PRO data collected may include study medication usage for study drug reconciliation reasons, symptom presence or severity to determine eligibility for trial participation, and responses over time to indicate improvement or worsening of the symptom/disease. 395 patients provided responses on compliance in their most recent clinical trial in the survey. 53.6% (N=210) reported always being compliant with completing patient diaries; 46.4% (N=185) reported that they were not always compliant. Patients in this survey reported a high level of non-compliance for patient diaries for their most recent clinical trial, which would have a high – moderate impact on the analyzability of the data. The patients who reported they were not always compliant (N=185) provided reasons for non-compliance with their diaries which include: they forgot, are too busy, are not able to access their diary, are too sick, or for other reasons. Each of these reasons were assessed for cause/risk, underlying issue and proactive mitigation options. For “they forgot”, a cause could include that the diary schedule is confusing, and a mitigation plan could include providing alerts to sites and reminders to patients. For “too busy”, the cause could be that patient burden is too high for that study, and a migration plan could include reducing the difficulty of the assessments included.


Although the reasons why patients are non-compliant can vary, it is important to assess the cause and risk of the non-compliance for each non-compliance reason. Underlying issues can be determined and proactive mitigation plans put in place in an attempt to optimize ePRO compliance on projects. As not all projects are the same - patient burden levels, therapeutic areas, and populations can vary largely - one must look at all of the project specifics / characteristics in order to determine a customized plan for success. This plan, along with an understanding of impacts of missing PRO responses, is important to minimizing the time and cost associated with running each clinical trial with ePRO assessments. Additional authors include: Jennifer Ross, Tracey Rothrock.

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