Assessing the impact of colonoscopy complications on use of colonoscopy among primary care physicians and other connected physicians: an observational study of older Americans.

OBJECTIVES: Psychological biases can distort treatment decision-making. The availability heuristic is one such bias, wherein events that are recent, vivid or easily imagined are readily 'available' to memory and are therefore judged more likely to occur than expected based on epidemiological data. We assessed if the occurrence of a serious colonoscopy complication for a primary care physician's patient influenced colonoscopy rates for the physician's other patients.

DESIGN: Longitudinal study with time-varying exposure variables.

SETTING/PARTICIPANTS: Individuals living in 51 hospital referral regions across the USA identified based on enrolment in fee-for-service Medicare during 2005-2010. We assigned patients to a primary care physician based on office visits during the prior 2 years.

EXPOSURES: For each physician in each month, we calculated the proportion of patients assigned to them who had a colonoscopy. We identified two serious complications of which the primary care provider would very likely be aware: gastrointestinal bleed or perforation leading to hospitalisation or death within 14 days of colonoscopy.

MAIN OUTCOME MEASURES: We employed Poisson regression models including physician fixed effects to assess the change in number of colonoscopies in the four quarters following an adverse colonoscopy event.

RESULTS: We identified 5 360 191 patients assigned to 30 704 physicians. 4864 physicians (16%) had at least one patient with an adverse event. The estimated change in the quarterly number of colonoscopies among physicians' patients was significantly lower in quarter 2 following an adverse colonoscopy event (change=-2.1% (95% CI -3.4 to -0.8%)), before returning to the rate expected in the absence of an adverse event.

CONCLUSIONS: Having a patient experience a serious adverse colonoscopy event was associated with a small and temporary decline in colonoscopy rates among a physician's other patients. This finding provides empirical evidence for the influence of notable adverse events on care, possibly due to the availability heuristic.