Patterns of use of flexible sigmoidoscopy, colonoscopy and gastroscopy: Data sources and Sample selection

Data sources

Data from the Alberta Health Care Insurance Plan (AHCIP) on physician payments for endoscopy-related services were obtained from Alberta Health and Wellness, the provincial government department responsible for administering health care. Data elements included patients’ date of birth, sex, postal code of residence at date of service, service date, procedure code, up to three diagnostic codes, facility code and service provider specialty. Annual population estimates for Alberta and each of Alberta’s 17 health regions for 1994 to 2002 were obtained from Alberta Health and Wellness.

Sample selection

Patients were included in the sample if they had at least one record for a flexible sigmoidoscopy, colonoscopy or gastroscopy (Schedule of Medical Benefits Codes 1.24B, 1.22 and 1.14) from January 1, 1994 to March 31, 2002. Records were also obtained for these patients for any large intestine polypectomy (55.21A). Patients were excluded if their postal code of residence at the time of the procedure was missing or outside of Alberta.

Direct age-sex standardized procedure rates were calculated using the 1991 Canadian population as the standard. Because endoscopy rates are expected to vary depending on the age, and possibly the sex, of individuals, differences in crude procedure rates between different populations could be due to true differences in procedure rates and/or differences in the sex and/or age distributions of each population. Direct age-sex standardized rates are derived by applying the age- and sex-specific rates observed in each population to a single standard population. Having a pharmacy you can trust is now easy and available any time you need: buy zoloft online click here to check and see how cheap your treatment could be while still being just as efficient and safe.

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