Association Between Age and Complications After Outpatient Colonoscopy.

Importance: There are insufficient data describing the incidence and risk factors of postcolonoscopy complications in older individuals. Objective: To assess the association between older age (≥75 years) and the risk of postcolonoscopy complications. Design, Setting, and Participants: This population-based retrospective cohort study included adults (≥50 years) undergoing outpatient colonoscopy between April 2008 and September 2017, identified from Ontario administrative databases. Individuals with inflammatory bowel disease and hereditary colorectal cancer syndromes were excluded. The study population was subdivided into a colorectal cancer screening-eligible cohort (patients aged 50-74 years) and an older cohort (patients aged ≥75 years). The statistical analysis was conducted from December 2018 to September 2019. Exposures: Older age (≥75 years). Main Outcomes and Measures: The primary outcome was postcolonoscopy complications, defined as the composite of hospitalization or emergency department visits in the 30-day period after the outpatient colonoscopy. Secondary outcomes included incidence of surgically treated colorectal cancer and all-cause mortality at 30 days. Independent variables associated with postcolonoscopy complications were also assessed. Results: The study sample included 38 069 patients; the mean (SD) age was 65.2 (10.1) years, there were 19 037 women (50.0%), and 27 831 patients (73.1%) underwent a first colonoscopy. The cumulative incidence of complications was 3.4% (1310 patients) in the overall population, and it was higher in individuals aged 75 years or older (515 of 7627 patients [6.8%]) than in screening-eligible cohort (795 of 30 443 patients [2.6%]) (P < .001). Independent risk factors for postcolonoscopy complications were age 75 years or older (odds ratio [OR], 2.3; 95% CI, 2.0-2.6), anemia (OR, 1.4; 95% CI, 1.2-1.7), cardiac arrhythmia (OR, 1.7; 95% CI, 1.2-2.2), congestive heart failure (OR, 3.4; 95% CI, 2.5-4.6), hypertension (OR, 1.2; 95% CI, 1.0-1.5), chronic kidney disease (OR, 1.8; 95% CI, 1.1-3.0), liver disease (OR, 4.7; 95% CI, 3.5-6.5), smoking history (OR, 3.2; 95% CI, 2.4-4.3), and obesity (OR, 2.3; 95% CI, 1.2-4.2). The number of previous colonoscopies was associated with a lower risk of complications (OR, 0.9; 95% CI, 0.7-1.0). The incidence of surgically treated colorectal cancer was higher in the older cohort than the screening-eligible cohort (119 patients [1.6%] vs 144 patients [0.5%]; P < .001). All-cause mortality rates were 0.1% overall (39 patients) and 0.1% (19 patients) for individuals aged 50 to 74 years and 0.2% (20 patients) for those aged 75 years and older (P < .001). Conclusions and Relevance: In this population-based cohort study of individuals living in southern Ontario, age of 75 years and older was associated with a higher risk of 30-day postprocedure complications after outpatient colonoscopy. These findings suggest that the decision to perform a colonoscopy should be carefully considered in patients older than 75 years, especially in the presence of comorbidities. Further studies are needed to better understand the benefits of invasive procedures as opposed to less invasive approaches for colorectal cancer screening and surveillance among older patients.