{Reference Type}: Journal Article
{Title}: Performance of the disease risk score in a cohort study with policy-induced selection bias.
{Author}: Tadrous M;Mamdani MM;Juurlink DN;Krahn MD;Lévesque LE;Cadarette SM;
{Journal}: J Comp Eff Res
{Volume}: 4
{Issue}: 6
{Year}: Nov 2015
{Factor}: 2.04
{DOI}: 10.2217/cer.15.40
{Abstract}: <B>OBJECTIVE: </B>To examine the performance of the disease risk score (DRS) in a cohort study with evidence of policy-induced selection bias.<BR><B>METHODS: </B>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.<BR><B>RESULTS: </B>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.<BR><B>CONCLUSIONS: </B>Our findings suggest that caution may be warranted when using DRS methods in cohort studies with policy-induced selection bias, further research is needed.