The Charlson Comorbidity Index Can Be Used to Identify Patients Who Are No Longer Appropriate for Surveillance Colonoscopy

Abstract

Purpose: The Charlson Comorbidity Index (CCI) is primarily used to predict survival among dialysis patients by assigning numerical weights to certain major medical problems and the patient's age. We sought to determine if the CCI can also be used to identify patients who, by virtue of significant comorbidity or advanced age, should no longer undergo surveillance colonoscopy. Methods: We performed a retrospective chart review of 1,554 patients who underwent a surveillance colonoscopy at the Manhattan Veterans Affairs Hospital from 2004-2011. Patients were included if they had a colonoscopy for a “history of colonic polyps,” “follow-up of colonic polyps,” or “established colonic polyps.” Patients were excluded if they had evidence of gastrointestinal bleeding, history of colorectal cancer, familial polyposis syndrome, or inflammatory bowel disease. We utilized the CCI to compare patients who died within five years of their surveillance colonoscopy with patients who lived longer than five years after their surveillance colonoscopy. The age at last colonoscopy, gender, race, number of medical conditions, albumin, and CCI level were recorded for each patient. An algorithm that factors in CCI and albumin levels was used to calculate one and two year survival probabilities for each patient. Only medical conditions that fell under CCI criteria were counted. The two groups were compared using a Student's two-tailed t-test. Results: Sixty patients died within five years of their last surveillance colonoscopy and were compared with our control group. The average time to death after colonoscopy was 31.8 months. None of the deaths were due to colorectal cancer. All patients were male. When comparing patients who died within five years to patients who were alive beyond that point, there were significant differences in CCI (5.53 and 4.25, respectively; p=0.005), one year survival probability (0.82 and 0.90, respectively; p=0.003), two year survival probability (0.67 and 0.79, respectively; p=0.001), and number of medical conditions (1.70 and 1.08, respectively; p=0.025). There was no significant difference in age among the two groups (75.12 for dead and 72.28 for alive; p=0.13). Conclusion: Patients who died within five years of colonoscopy had a significantly higher CCI and lower one- and two-year survival probabilities compared to those who are alive at least five years after their colonoscopy. Though there are clear recommendations for ages at which to discontinue screening colonoscopy, similar guidelines for stopping surveillance colonoscopy are currently lacking. CCI could be used to help determine which patients would no longer benefit from continued surveillance colonoscopy by evaluating their mortality risk.