Note: Attached documents contain full case definition and two different control definitions. One is for controls with 2 years of follow up, the other for controls with 1 year of follow up. All available controls with 2 years of follow up were used in Vanderbilt's study. The control population was supplemented by controls with only 1 year of follow up. At the time of study, many of the available controls had experienced their qualifying events somewhat recently and 2 years had not yet passed for full follow up.
Validation at Vanderbilt revealed compliance issues and other potential problems in about half of the potential cases. Controls were likely to be true controls. See linked manuscript (Delaney et al.) for full details of performance.