Table 1:

Group definitions and attrition. Intervention = ATTAIN + Usual Care; Control = Usual Care alone. ‘previously screened (*)’ refers to office-based screening for unhealthy drinking behavior having been completed in the year prior to this study with resulting negative screens (patients did not meet criteria for unhealthy drinking behavior). ‘no previous screen’ refers to a lack of screening having been done for unhealthy drinking behavior in the year prior to this study. Exclusions in the intervention group were for registry members who did not have an active account on the KPSC electronic medical record patient portal

Group	Characteristics	Total, N (Before Exclusions)	n (Intervention)	n (Control)
1	Pre-operative, previously screened (*)	1457	737(63 excluded out of 800)	657
2	Preop (2 a) and postop (2b), no previous screen	1157	745(55 excluded out of 800)	357
3	Post-operative, previously screened (*)	1916	767(33 excluded out of 800)	1116
Total		4530	2249 (151 excluded out of 2400)	2130