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Performance of the disease risk score in a cohort study with policy-induced selection bias
Mina Tadrous1,2,3, Muhammad M Mamdani1,2,3,4, David N Juurlink2,5
1Leslie Dan Faculty of Pharmacy, University of Toronto, 144 College Street, Toronto, ON, M5S 3M2, Canada.
Aim:
To examine the performance of the disease risk score (DRS) in a cohort study with evidence of policy-induced selection bias.
Methods:
We examined two cohorts of new users of bisphosphonates. Estimates for 1-year hip fracture rates between agents using DRS, exposure propensity scores and traditional multivariable analysis were compared.
Results:
The results for the cohort with no evidence of policy-induced selection bias showed little variation across analyses (-4.1-2.0%). Analysis of the cohort with evidence of policy-induced selection bias showed greater variation (-13.5-8.1%), with the greatest difference seen with DRS analyses.
Conclusion:
Our findings suggest that caution may be warranted when using DRS methods in cohort studies with policy-induced selection bias, further research is needed.
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