Implement Stratifications in CohortDiagnostics

[kmkostka]

Each target cohort will be analysed in full and stratified on factors based on the following pre-index characteristics, all stratum are pending meeting minimum reportable cell counts (as specified by data owners) and where possible, may include:
● Follow-up time: overall, with full 30 days follow-up, without full 30 days follow-up
● Sex (Male vs. Female)
● Those with another type of specified hand surgery prior to index procedure (eg denervation prior to arthrodesis)
● All reportable age groups as well as specifically:
○ Young age ( Age >=35)
○ Elderly (Age >= 65). If sample size allows, results will be reported stratified in the following age categories: 65-84 years, and >=85 years, or in finer age strata (65-69, 70-74, 75-79, 80-84, >=85 years)