Diagnostic Assessment of Assumptions for External Validity
Year: 2018
Type: article
Abstract: BACKGROUND: Methods developed to estimate intervention effects in external target populations assume that all important effect measure modifiers have been identified and appropriately modeled. Propensity score-based diagnostics can be used to assess the plausibility of these assumptions for weighting methods. METHODS: We demonstrate the use of these diagnostics when assessing the transportability of treatment effects from the standard of care for metastatic colorectal cancer control arm in a phase III trial (HORIZON III) to a target population of 1,942 Medicare beneficiaries age 65+ years. RESULTS: In an unadjusted comparison, control arm participants had lower mortality compared with target population patients treated with the standard of care therapy (trial vs. target hazard ratio [HR] = 0.72, 95% confidence interval [CI], 0.58, 0.89). Applying inverse odds of sampling weights attenuated the trial versus target HR (weighted HR = 0.96, 95% CI = 0.73, 1.26). However, whether unadjusted or weighted, hazards did not appear proportional. At 6 months of follow-up, mortality was lower in the weighted trial population than the target population (weighted trial vs. target risk difference [RD] = -0.07, 95% CI = -0.13, -0.01), but not at 12 months (weighted RD = 0.00, 95% CI = -0.09, 0.09). CONCLUSION: These diagnostics suggest that direct transport of treatment effects from HORIZON III to the Medicare population is not valid. However, the proposed sampling model might allow valid transport of the treatment effects on longer-term mortality from HORIZON III to the Medicare population treated in clinical practice. See video abstract at, http://links.lww.com/EDE/B435.
Source: Epidemiology
Institution: University of North Carolina at Chapel Hill
Language: English
Subfield: Statistics and Probability
Field: Mathematics
Domain: Physical Sciences
Open Access status: green
Funders: Pharmaceutical Research and Manufacturers of America Foundation, National Institutes of Health, National Institute on Aging, National Heart, Lung, and Blood Institute, National Cancer Institute, National Center for Advancing Translational Sciences, Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill
Awards: Methods for Estimating Sex Differences in Safety and Effectiveness of Drugs, North Carolina Translational & Clinical Sciences Institute (NC TraCS), UNC Oncology K12, Propensity scores and preventive drug use in the elderly, G4720334866, North Carolina Translational and Clinical Science Institute (NC TraCS), PROMIS Validation in Prospective Population-based Prostate Cancer Research Study, Propensity scores and preventive drug use in the elderly
OpenAlex ID: W2892989662