Potentially inappropriate screening colonoscopy in Medicare patients: variation by physician and geographic region

Inappropriate use of colonoscopy involves unnecessary risk for older patients and consumes resources that could be used more effectively.

To determine the frequency of potentially inappropriate colonoscopy in Medicare beneficiaries in Texas and to examine variation among physicians and across geographic regions.

This retrospective cohort study used 100% Medicare claims data for Texas and a 5% sample from the United States from 2000 through 2009. We identified Medicare beneficiaries aged 70 years or older who underwent a colonoscopy from October 1, 2008, through September 30, 2009.

Colonoscopies were classified as screening in the absence of a diagnosis suggesting an indication for the procedure. Screening colonoscopy was considered potentially inappropriate on the basis of patient age or occurrence too soon after colonoscopy with negative findings. The percentage of patients undergoing potentially inappropriate screening colonoscopy was estimated for each colonoscopist and hospital service area.

A large percentage of colonoscopies performed in older adults were potentially inappropriate: 23.4% for the overall Texas cohort and 9.9%, 38.8%, and 24.9%, respectively, in patients aged 70 to 75, 76 to 85, or 86 years or older. There was considerable variation across the 797 colonoscopists in the percentages of colonoscopies performed that were potentially inappropriate. In a multilevel model including patient sex, race or ethnicity, number of comorbid conditions, educational level, and urban or rural residence, 73 colonoscopists had percentages significantly above the mean (23.9%), ranging from 28.7% to 45.5%, and 119 had percentages significantly below the mean (23.9%), ranging from 6.7% to 18.6%. The colonoscopists with percentages significantly above the mean were more likely to be surgeons, graduates of US medical schools, medical school graduates before 1990, and higher-volume colonoscopists than those with percentages significantly below the mean. Colonoscopist rankings were fairly stable over time (2006-2007 vs 2008-2009). There was also geographic variation across Texas and the United States, with percentages ranging from 13.3% to 34.9% in Texas and from 19.5% to 30.5% across the United States.

Many colonoscopies performed in older adults may be inappropriate. The likelihood of undergoing potentially inappropriate colonoscopy depends in part on where patients live and what physician they see.