Incidence of and Risk Factors for Systemic Adverse Events After Screening or Primary Diagnostic Colonoscopy: A Nationwide Cohort Study.

OBJECTIVES: To estimate the systemic serious adverse event (SAE) rates after colonoscopy and to identify their risk factors.

METHODS: A nationwide cohort study was conducted using the comprehensive French claims databases SNDS (National Health Data System). Patients aged 30 years and over who underwent a first screening or diagnostic colonoscopy in 2010-2015 were included. The rates of cardiovascular and renal SAEs were estimated within 5 days after colonoscopy. The standardized incidence ratios were calculated to compare these incidence rates with those of the same events in the general population, and the associated risk factors were assessed by multilevel logistic regression.

RESULTS: Among the 4,088,799 included patients (median age, 59 years [interquartile range = 50-67]; 55.2% women; 30.1% with a Charlson index score ≤1), the 5-day SAE incidence rate was 2.8/10,000 procedures for shock, 0.87/10,000 for myocardial infarction, 1.9/10,000 for stroke, 2.9/10,000 for pulmonary embolism, 5.5/10,000 for acute renal failure, and 3.3/10,000 for urolithiasis. These SAEs occurred 3.3 to 15.8 times more often during the first 5 days after colonoscopy than expected in the general population. Thirty-day mortality rates ranged from 2.2/1,000 cases of urolithiasis to 268.1/1,000 cases of shock. Increasing age was associated with an increasing incidence of SAEs. Risks of shock and acute renal failure were associated with a greater number of comorbidities than the other SAEs. Colonoscopies in university hospitals were associated with higher risks, reflecting patient selection processes.

DISCUSSION: The systemic SAEs can be associated with a substantial mortality. They should be taken into account when deciding colonoscopy, in addition to perforation and bleeding, particularly in elderly patients with multiple comorbidities.