Patient Safety Tip of the Week

June 26, 2018††† Infection Related to Colonoscopy



Several years ago we were trying to help a hospital find benchmarks for colonoscopy complications. We were amazed that such benchmarks were not readily available. We discussed complications of colonoscopy in our November 15, 2011 Patient Safety Tip of the Week ďRethinking ColonoscopyĒ and noted that the few studies done did not separate out screening colonoscopies from diagnostic or therapeutic ones. Rates also depend on whether polypectomy was done, and also relate to the age of the population and associated comorbidities (Warren 2009).All these factors make it extremely difficult to compare rates of colonoscopy complications across facilities. Some of the same factors likely explain why rates at free standing ambulatory sites tend to be lower than at hospital-based endoscopy units.


Then, in our March 1, 2016 Patient Safety Tip of the Week ďColonoscopy ComplicationsĒ, we noted a study from researchers at the Yale-New Haven Center for Outcomes Research and Evaluation (CORE) (Ranasinghe 2016) which found outpatient colonoscopies were followed by unplanned hospital visits within 7 days at an overall rate of 16.3/1000 colonoscopies, or a rate of about 1.6%. Hemorrhage, abdominal pain, and perforation were the most common causes of unplanned hospital visits.


In those columns, infections related to colonoscopies never were a significant part of our discussions. So we were quite taken aback at a recent study by researchers at Johns Hopkins (Wang 2018) that showed unexpectedly high rates of infection following colonoscopy (and also endoscopy) at ambulatory surgery centers (ASCís).


The rates of postendoscopic infection per 1000 procedures within 7 days were 1.1 for screening colonoscopy, and 1.6 for non-screening colonoscopy (and 3.0 for esophagogastroduodenoscopies).


Predictors of postendoscopic infection included recent history of hospitalization or endoscopic procedure; concurrence with another endoscopic procedure; low procedure volume or non-freestanding ASC; younger or older age; black or Native American race and male sex. Rates of 7-day postendoscopic infections varied widely by ASC, ranging from 0 to 115 per 1000 procedures for screening colonoscopy, 0 to 132 for non-screening colonoscopy.


The most common organisms associated with infections were E. coli, Klebsiella, Clostridium difficile, and Staphylococcus species. And among those unplanned postprocedure visits, over 60% required hospitalization.


Infection as a complication of colonoscopy has caught most of us by surprise. Even the recently updated American Cancer Society guidelines (Wolf 2018) on screening for colorectal cancer donít discuss infection. Those guidelines state ďThe principal recognized harms of CRC screening, which are rare, are those associated with colonoscopy (bleeding, perforation, cardiorespiratory complications of sedation) as a primary screening test or as a follow‐up of other positive noncolonoscopy tests.Ē


Perhaps many physicians performing colonoscopies have been unaware of their patients developing infectious complications because they had either unplanned emergency department visits or unplanned hospital admissions. The Hopkins researchers used an all-payer claims database with data from six states to track infection-related emergency room visits and unplanned inpatient admissions within seven and 30 days after a colonoscopy or EGD. Many ASCís lack interoperability with hospital-based IT systems, so they often have no way of tracking such infectious complications.


The variation in infection rates across ASCís was striking, with rates at some ASCs more than 100 times higher than expected.


So what does this mean for you? It obviously depends on whether you are a provider or a consumer. If you are an ASC performing endoscopies, you better find out what your rates of complications, including infections, really are (and stratify them by screening vs. nonscreening colonoscopy and whether polypectomy was performed). If you have no way of getting data from area hospitals regarding ED visits or hospitalizations of your patients after colonoscopy, you need to routinely contact your patients to find out whether complications occurred. Many ASCís already make a phone call to patients 24-48 hours after a procedure, but the Hopkins study would suggest you need to also contact them later (perhaps at 30 days) to ensure you are identifying all complications.


And if you are a consumer, youíll want to know the ASCís rate for complications, infectious or otherwise, for colonoscopies (or EGDís). If you canít get that data, consider using a different ASC.


Colonoscopy is still a very valuable tool in the prevention and management of colorectal cancer. And guidelines for screening are expanding to begin screening earlier. The most recent American Cancer Society guidelines (Wolf 2018) recommend that adults aged 45 years and older with an average risk of CRC undergo regular screening with either a high‐sensitivity stool‐based test or a structural (visual) examination, depending on patient preference and test availability. As a part of the screening process, all positive results on noncolonoscopy screening tests should be followed up with timely colonoscopy. The recommendation to begin screening at age 45 years is a qualified recommendation. The recommendation for regular screening in adults aged 50 years and older is a strong recommendation.


The lack of accurate data on the complications of colonoscopy has made it difficult to assess the risk:benefit equations for colonoscopy as a screening tool for colorectal cancer. In fact, in our March 1, 2016 Patient Safety Tip of the Week ďColonoscopy ComplicationsĒ we noted that the jump to colonoscopy as the most recommended tool was based upon the assumption that colonoscopy was more comprehensive than sigmoidoscopy (which had been shown to reduce colorectal cancer mortality) but that untoward consequences of colonoscopy had not really been factored into decisions.


It's incumbent upon all facilities performing colonoscopies to have accurate data on complications of these procedures. This obviously should apply not only to ASCís but also to hospital-based colonoscopies. Many facilities may be surprised they are not doing quite as well as they thought they were.







Warren J.L., Klabunde C.N., Mariotto A.B., et al:  Adverse events after outpatient colonoscopy in the Medicare population.  Ann Intern Med 2009; 150:  849-857



Ranasinghe I, Parzynski CS, Searfoss R, et al. Differences in Colonoscopy Quality Among Facilities: Development of a Post-Colonoscopy Risk-Standardized Rate of Unplanned Hospital Visits. Gastroenterology 2016; 150(1): 103-113



Wang P, Xu T, Ngamruengphong S, Makary MA, et al. Rates of infection after colonoscopy and osophagogastroduodenoscopy in ambulatory surgery centres in the USA. Gut 2018; Published Online First: 10 Apr 2018



Wolf AMD, Fontham ETH, Church TR, et al. Colorectal cancer screening for average‐risk adults: 2018 guideline update from the American Cancer Society. CA: A Cancer Journal for Clinicians 2018; First published: 30 May 2018





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