Colonoscopy for Ischemic Colitis Is Associated With Less Risk of Readmission: A Nationwide Study of 30-Day Readmission Rates, Outcomes, and Predictors

Introduction: Ischemic colitis (IC) is the most common cause of intestinal ischemia and its incidence increases with age and may have a significant representation in morbidity and mortality. There is paucity of data regarding 30-day specific readmission rates, causes and predictors. We aim to identify 30-day readmission rate, causes, and predictors of readmission in ischemic colitis. Methods: Retrospective cohort study using the 2019 National Readmission Database of adult patients that had an index admission (IA) for IC from the month of January to November and were readmitted within 30-days of discharge. ICD-10CM/PCS codes were utilized to identified diagnosis and procedures. The primary outcome was readmission of any cause. Secondary outcomes were mortality, resource utilization (length of stay (LOS), total hospitalization costs and charges) associated with readmission. Independent risk factors for readmission were identified using Cox regression analysis. Results: A total of 6,853 Ischemic Colitis (IC) patients were identified in 2019. Out of which 762 (11.0%) were readmitted in 30 days. The number one cause of readmission was sepsis. A total of 325 patients died during the IA and additional 30 patients died within 30 days of discharge. The respective mortality rates for IA and readmission were 4.7% and 4.0% (P = 0.79). Readmitted patients had significantly increased LOS (5.7 vs 6.4 days; P = < 0.01). The total economic burden of readmission was $12 million in total costs and $51.4 million in total charges. Independent predictors of readmission were: patients discharged to short term hospital (aHR:4.54, P = 0.02), nursing skill facility (aHR:1.98, P = < 0.01), and home health care (aHR:2.08, P = < 0.01), a Charlson comorbidity index score ≥ 2 (aHR:1.63, P = 0.02) and being admitted at large size hospital (aHR:1.37, P = 0.04). Having private insurance as primary payer (aHR:0.59, P = < 0.01) and undergoing to colonoscopy (aHR:0.66, P = < 0.01) were associated with lower odds of readmission (Table 1). Conclusion: 30-day readmission rates after admission for IC are high with 50% of readmissions secondary to sepsis. Undergoing colonoscopy during the IA is associated with 34% less risk of readmission and disposition to other facilities seems to increase the risk of early readmission. Further prospective studies are needed to determine the mechanisms behind these findings and strategies should be carried out to decrease readmission rates. Table 1. - Independent Predictors of 30-days Readmission Variable Hazard ratio (95% confidence interval) P value Female 0.92 (0.72-1.18) 0.53 Age 0.98 (0.97-1.01) 0.08 Disposition of patient Discharged to home or self-care Reference Reference Short-term hospital 4.54 (1.19-17.30) 0.02 Skilled nursing facility/intermediate care 1.98 (1.40-2.81) < 0.01 Home health care 2.08 (1.55-2.79) < 0.01 Against medical advice 2.37 (0.96-5.81) 0.06 Insurance Provider Medicare Reference Reference Medicaid 1.20 (0.77-1.88) 0.42 Private 0.59 (0.41-0.87) < 0.01 Uninsured 0.74 (0.30-1.182) 0.51 Median Income in patient zip code $1 - 42,999 Reference Reference $43,000-53,999 0.90 (0.68-1.21) 0.46 $54,000-70,999 1.63 (1.07-2.49) 0.22 $≥71,000 1.79 (1.24-2.59) < 0.01 Patient residence Large metropolitan area with at least 1 million residents Reference Reference Small metropolitan areas with less than 1 million residents 0.91 (0.68-1.21) 0.51 Micropolitan areas 0.82 (0.61-1.10) 0.18 Not metropolitan or micropolitan (nonurban residual) 0.78 (0.57-1.08) 0.14 Charlson Comorbidity Index Score 0 Reference Reference 1 1.15 (0.78-1.69) 0.46 2 1.63 (1.07-2.48) 0.02 ≥3 1.79 (1.24- 2.59) < 0.01 In-hospital procedures Colonoscopy 0.66 (0.53-0.83) < 0.01 Colectomy 1.29 (0.89-1.88) 0.17 Parenteral nutrition 1.02 (0.58-1.82) 0.92 Other Comorbidities Obesity 0.79 (0.58-1.09) 0.15 Type 2 DM 1.22 (0.96-1.55) 0.09 Alcohol use disorder 1.37 (0.78-2.40) 0.25 History of tobacco use 0.20 (0.26-1.55) 0.12 Opioid use disorder 0.48 (0.19-1.16) 0.10 Vitamin D deficiency 1.82 (0.94-3.53) 0.07 Malnutrition 0.85 (0.59-1.23) 0.40 Hospital bed size Small Reference Reference Medium 1.26 (0.89-1.79) 0.18 Large 1.37 (1.01-1.88) 0.04 In-hospital Complications Shock 1.05 (0.62-1.79) 0.85 Mechanical ventilation 0.95 (0.48-1.86) 0.88 Teaching hospital 1.08 (0.83-1.41) 0.54