Table 1.

Combinations of Confounder Summary Score, Confounding Adjustment Method, Data-Sharing Approach, and Outcome Type Evaluated

Confounding adjustment method & data-sharing approach	Statistical analysis performed at the analysis center
	Binary outcomea	Time-to-event outcomeb
Propensity score
Stratification
Pooled individual-level	PS- and site-stratified (Reference)	PS- and site-stratified (Reference)
Risk-set	PS- and site-stratified	Case-centered logistic regressionc
Summary-tabled	PS- and site-stratified	PS- and site-stratified conditional Poisson regression
Effect-estimate	Inverse variance-weighted meta-analysis	Inverse variance-weighted meta-analysis
Matching
Pooled individual-level	PS-matched, site-stratified (Reference)	PS-matched, site-stratified (Reference)
Risk-set	PS-matched, site-stratified	Case-centered logistic regression
Summary-table	PS-matched, site-stratified	PS-matched, site-stratified conditional Poisson regression
Effect-estimate	Inverse variance-weighted meta-analysis	Inverse variance-weighted meta-analysis
Inverse probability weighting
Pooled individual-level	Inverse probability weighted, site-stratified (Reference)	Inverse probability weighted, site-stratified (Reference)
Risk-set	Inverse probability weighted, site-stratified	Inverse probability weighted, site-stratified
Summary-table	Not established	Not established
Effect-estimate	Inverse variance-weighted meta-analysis	Inverse variance-weighted meta-analysis
Matching weighting
Pooled individual-level	Matching weighted, site-stratified (Reference)	Matching weighted, site-stratified (Reference)
Risk-set	Matching weighted, site-stratified	Matching weighted, site-stratified
Summary-table	Not established	Not established
Effect-estimate	Inverse variance-weighted meta-analysis	Inverse variance-weighted meta-analysis
Disease risk score
Stratification
Pooled individual-level	DRS- and site-stratified (Reference)	DRS- and site-stratified (Reference)
Risk-set	DRS- and site-stratified	Case-centered logistic regression
Summary-table	DRS- and site-stratified	DRS- and site-stratified conditional Poisson regression
Effect-estimate	Inverse variance-weighted meta-analysis	Inverse variance-weighted meta-analysis
Matching
Pooled individual-level	DRS-matched, site-stratified (Reference)	DRS-matched, site-stratified (Reference)
Risk-set	DRS-matched, site-stratified	Case-centered logistic regression
Summary-table	DRS-matched, site-stratified	DRS-matched, site-stratified conditional Poisson regression
Effect-estimate	Inverse variance-weighted meta-analysis	Inverse variance-weighted meta-analysis
Inverse probability weighting
Pooled individual-level	Not established	Not established
Risk-set	Not established	Not established
Summary-table	Not established	Not established
Effect-estimate	Not established	Not established
Matching weighting
Pooled individual-level	Not established	Not established
Risk-set	Not established	Not established
Summary-table	Not established	Not established
Effect-estimate	Not established	Not established

Note: DRS= disease risk score; PS= propensity score

^aUnless otherwise specified, logistic regression was used to obtain estimates of odds ratios and their 95% confidence intervals for binary outcomes.

^bUnless otherwise specified, Cox proportional hazards regression was used to obtain estimates of hazard ratios and their 95% confidence intervals for time-to-event outcomes.

^cCase-centered logistic regression is a logistic regression model with the proportion of exposed outcome events among all events as the dependent variable and the log odds of having the study exposure in the risk-set as the independent variable, specified as an offset (9). Each risk-set, anchored by a unique outcome event time, comprises patients who experienced the outcome and patients who were still at risk of developing the outcome at that time point. When combined with confounder summary scores, the risk-set is created within a matched cohort or stratum defined by the confounder summary score within a site. In this particular analysis, each risk-set comprised the patient or patients who developed the outcome plus all other at-risk patients belonging to the same propensity score stratum at the time of the event within each site.

^dIn situations where the regression-based analysis was not feasible for the summary-table data-sharing approach, we used the Mantel-Haenszel method to compute a weighted estimate for the desired effect estimate.