Stratifying Outcomes by Sub-populations
Once the numerator and denominator populations have been configured, the HOME Cell allows users to stratify the outcome by sub-populations that are defined using the i2b2 Query Tool. During query execution, the HOME Cell first computes the overall counts in the numerator and denominator for each reference interval and then computes numerator and denominator counts for the subgroups listed in the “Strata” tab by limiting the denominator population to those individuals who are in each strata. For example, to stratify obesity rates by race, the HOME Cell user would define cohorts of individuals with the races of interest using the i2b2 Query Tool and save the queries as show below:
ANY i2b2 Query Tool query can be used as a strata allowing a vast array of subanalyses including race, gender, insurance, clinical data, census tract of residence.