Table 2.

Summary of Methods Used to Adjust for Confounding of Measured Variables When Comparing Multiple Drug Exposures

Analytic strategy	Method employed in this study
Conventional multivariable model	multivariable Cox proportional hazard model that included terms for the exposure variables of interest (3 dummy terms, RSD, CCT, RAL) and a term for each potential confounder
Exposure propensity score (EPS)	Single Model EPS created state-specific EPS for RSD, CCT, RAL in full cohort using multinomial logistic regression fit single Cox proportional hazard model adjusting for EPS quintiles (12 dummies, 4 for each drug exposure), stratified by state
	Separate Model EPS three contrast cohorts RSD + ALD CCT + ALD RAL + ALD within each contrast cohort created state-specific EPS using logistic regression (ALD referent/unexposed) adjusted for EPS quintiles as 4 dummies in Cox proportional hazard model, stratified by state
Disease risk score (DRS)	Full Cohort DRS created state-specific DRS equations by including all relevant confounders + exposure of interest calculated individual DRS by multiplying covariate regression coefficients with individual covariate values (exposure variables omitted from equation, i.e., set to zero)
	Unexposed DRS same as “full cohort,” however step 1 restricted to unexposed (ALD), and thus exposure variables also not applicable

ALD=alendronate, CCT=nasal calcitonin, RAL=raloxifene, RSD=risedronate