Incidence of Gall Bladder Related Events Among Type 2 Diabetes Patients

Trial description: Modification of bile acid reabsorption is sensed by the liver, resulting in compensatory adjustments in bile acid synthesis which alter gallbladder contents. This change in concentration of bile acids in bile may affect the solubility of cholesterol leading to microcrystallization and gallstone formation. Bile acid sequestrants reduce the enterohepatic circulation of bile acids, while fibrates alter bile acid metabolism. As a result, these 2 classes of medicines can be used to investigate the effect of pertubating bile acid metabolism on the risk of gall bladder disease. This study will descriptively characterize the risk of gall bladder disease among patients with and without T2DM and those exposed to diabetes medications of interest and bile acid sequestrants as well as fibrates. Primary objectivesTo describe the characteristics (age, gender, concomitant medications, history of co-morbid conditions) of the following exposure groups overall and stratified by history of gall bladder disease:1. T2DM patients2. Non-T2DM patients3. T2DM patients using metformin (new and prevalent users)4. T2DM patients using sulphonylureas (new and prevalent users, excluding those using metformin)5. T2DM patients using metformin (new and prevalent users) and newly using bile acid sequestrants6. T2DM patients using sulphonylureas (new and prevalent users) (excluding those using metformin) and newly using bile acid sequestrants.7. T2DM patients using fibratesTo descriptively compare the incidence of gall bladder disease (gallstones, cholestectomy, cholelithiasis, acute cholecystitis, chronic cholecystitis) across exposure groups and stratified by history of gall bladder related disease.Secondary objectiveTo descriptively compare the incidence of gall bladder disease (gallstones, cholestectomy, cholelithiasis, acute cholecystitis, chronic cholecystitis) between T2DM patients using fibrates and T2DM patients not using fibrates and stratified by history of gall bladder related disease.T2DM patients and age matched non-T2DM patients:A cohort of adult (64 years ≤age ≥18 years) patients with T2DM enrolled in Truven during January 1, 2004- September 2013 and having medical and pharmacy coverage will be selected from the Truven database. Patients must have an ICD-9 code for T2DM during the study period and at least 12 months of continuous enrolment before their code and ≥ 3 months after their code. The date of the first occurrence of an ICD-9 code for T2DM, with at least 12 months of follow-up before the code, will be considered the index date. Patients with an ICD-9 code for any of the gall bladder related events during the 12 months of enrolment before the first occurrence of a code for T2DM, will be considered to have a history of gall bladder disease and patients without ICD-9 codes for gall bladder disease during this period will be considered not to have a history of gall bladder disease. A second cohort of patients without a code for T2DM over their entire medical history during the study period and with medical and pharmacy coverage, similarly classified in terms of history of gall bladder related events (no history of gall bladder disease within the 12 months before their selection), will be randomly selected and age and timing of the start of a patients follow-up will be balanced across the overall group of T2DM non-T2DM patients. Patients without T2DM must have 12 months continuous enrolment before and ≥ 3 months after the start of their follow-up. Patients will be followed from the date of their ICD-9 code for T2DM or from the date of their first medical record within the study period for those within the non-T2DM cohort until the first occurrence of a gall bladder related event, loss of pharmacy benefits, disenrollment from the database, turning 65 years old, or end of the study period, whichever comes first. Users of metformin and sulphonylureas will be selected from the adult cohort of T2DM patients for the next section of the study.New and Prevalent Users of Metformin and Sulphonylureas:Patients must have at least 2 prescriptions for metformin or a sulphonylurea, after the index date (date of first T2DM ICD-9 code during the study period) and ≥ 3 months of follow-up after their first recorded medication use (after the index date) and will be stratified by their history of gall bladder related events in the 12 months before their first recorded ICD-9 code for T2DM and the time period between the first recorded diagnosis and the first use of metformin or sulphonylurea.