Errors in self-reports of health services use impact on Alzheimer disease clinical trial designs

Research output: Contribution to journalArticle

5 Citations (Scopus)

Abstract

Background: Most Alzheimer disease clinical trials that compare the use of health services rely on reports of caregivers. The goal of this study was to assess the accuracy of self-reports among older adults with Alzheimer disease and their caregiver proxy respondents. This issue is particularly relevant to Alzheimer disease clinical trials because inaccuracy can lead both to loss of power and increased bias in study outcomes. Methods: We compared respondent accuracy in reporting any use and in reporting the frequency of use with actual utilization data as documented in a comprehensive database. We next simulated the impact of underreporting and overreporting on sample size estimates and treatment effect bias for clinical trials comparing utilization between experimental groups. Results: Respondents self-reports have a poor level of accuracy with k-values often below 0.5. Respondents tend to underreport use even for rare events such as hospitalizations and nursing home stays. In analyses simulating underreporting and overreporting of varying magnitude, we found that errors in self-reports can increase the required sample size by 15% to 30%. In addition, bias in the reported treatment effect ranged from 3% to 18% due to both underreporting and overreporting errors. Conclusions: Use of self-report data in clinical trials of Alzheimer disease treatments may inflate sample size needs. Even when adequate power is achieved by increasing sample size, reporting errors can result in a biased estimate of the true effect size of the intervention.

Original languageEnglish
Pages (from-to)75-81
Number of pages7
JournalAlzheimer Disease and Associated Disorders
Volume29
Issue number1
DOIs
StatePublished - Mar 6 2015

Fingerprint

Sample Size
Self Report
Health Services
Alzheimer Disease
Clinical Trials
Caregivers
Proxy
Nursing Homes
Hospitalization
Therapeutics
Outcome Assessment (Health Care)
Databases
Surveys and Questionnaires
Power (Psychology)

Keywords

  • Alzheimer disease
  • clinical trials
  • health care utilization
  • health services research
  • self-reports

ASJC Scopus subject areas

  • Geriatrics and Gerontology
  • Psychiatry and Mental health
  • Gerontology
  • Clinical Psychology

Cite this

@article{871716351aa44b47b72746e1dab73088,
title = "Errors in self-reports of health services use impact on Alzheimer disease clinical trial designs",
abstract = "Background: Most Alzheimer disease clinical trials that compare the use of health services rely on reports of caregivers. The goal of this study was to assess the accuracy of self-reports among older adults with Alzheimer disease and their caregiver proxy respondents. This issue is particularly relevant to Alzheimer disease clinical trials because inaccuracy can lead both to loss of power and increased bias in study outcomes. Methods: We compared respondent accuracy in reporting any use and in reporting the frequency of use with actual utilization data as documented in a comprehensive database. We next simulated the impact of underreporting and overreporting on sample size estimates and treatment effect bias for clinical trials comparing utilization between experimental groups. Results: Respondents self-reports have a poor level of accuracy with k-values often below 0.5. Respondents tend to underreport use even for rare events such as hospitalizations and nursing home stays. In analyses simulating underreporting and overreporting of varying magnitude, we found that errors in self-reports can increase the required sample size by 15{\%} to 30{\%}. In addition, bias in the reported treatment effect ranged from 3{\%} to 18{\%} due to both underreporting and overreporting errors. Conclusions: Use of self-report data in clinical trials of Alzheimer disease treatments may inflate sample size needs. Even when adequate power is achieved by increasing sample size, reporting errors can result in a biased estimate of the true effect size of the intervention.",
keywords = "Alzheimer disease, clinical trials, health care utilization, health services research, self-reports",
author = "Christopher Callahan and Wanzhu Tu and Stump, {Timothy E.} and Daniel Clark and Kathleen Unroe and Hugh Hendrie",
year = "2015",
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language = "English",
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journal = "Alzheimer Disease and Associated Disorders",
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T1 - Errors in self-reports of health services use impact on Alzheimer disease clinical trial designs

AU - Callahan, Christopher

AU - Tu, Wanzhu

AU - Stump, Timothy E.

AU - Clark, Daniel

AU - Unroe, Kathleen

AU - Hendrie, Hugh

PY - 2015/3/6

Y1 - 2015/3/6

N2 - Background: Most Alzheimer disease clinical trials that compare the use of health services rely on reports of caregivers. The goal of this study was to assess the accuracy of self-reports among older adults with Alzheimer disease and their caregiver proxy respondents. This issue is particularly relevant to Alzheimer disease clinical trials because inaccuracy can lead both to loss of power and increased bias in study outcomes. Methods: We compared respondent accuracy in reporting any use and in reporting the frequency of use with actual utilization data as documented in a comprehensive database. We next simulated the impact of underreporting and overreporting on sample size estimates and treatment effect bias for clinical trials comparing utilization between experimental groups. Results: Respondents self-reports have a poor level of accuracy with k-values often below 0.5. Respondents tend to underreport use even for rare events such as hospitalizations and nursing home stays. In analyses simulating underreporting and overreporting of varying magnitude, we found that errors in self-reports can increase the required sample size by 15% to 30%. In addition, bias in the reported treatment effect ranged from 3% to 18% due to both underreporting and overreporting errors. Conclusions: Use of self-report data in clinical trials of Alzheimer disease treatments may inflate sample size needs. Even when adequate power is achieved by increasing sample size, reporting errors can result in a biased estimate of the true effect size of the intervention.

AB - Background: Most Alzheimer disease clinical trials that compare the use of health services rely on reports of caregivers. The goal of this study was to assess the accuracy of self-reports among older adults with Alzheimer disease and their caregiver proxy respondents. This issue is particularly relevant to Alzheimer disease clinical trials because inaccuracy can lead both to loss of power and increased bias in study outcomes. Methods: We compared respondent accuracy in reporting any use and in reporting the frequency of use with actual utilization data as documented in a comprehensive database. We next simulated the impact of underreporting and overreporting on sample size estimates and treatment effect bias for clinical trials comparing utilization between experimental groups. Results: Respondents self-reports have a poor level of accuracy with k-values often below 0.5. Respondents tend to underreport use even for rare events such as hospitalizations and nursing home stays. In analyses simulating underreporting and overreporting of varying magnitude, we found that errors in self-reports can increase the required sample size by 15% to 30%. In addition, bias in the reported treatment effect ranged from 3% to 18% due to both underreporting and overreporting errors. Conclusions: Use of self-report data in clinical trials of Alzheimer disease treatments may inflate sample size needs. Even when adequate power is achieved by increasing sample size, reporting errors can result in a biased estimate of the true effect size of the intervention.

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