Northern Latitude but Not Season Is Associated with Increased Rates of Hospitalizations Related to Inflammatory Bowel Disease: Results of a Multi-Year Analysis of a National Cohort

<div><p>Background and Aims</p><p>There is growing evidence that the incidence and severity of inflammatory bowel disease (IBD) may be geographically and seasonally related. Why these associations are observed remains unclear. We assessed the impact of geographic location, season, and exposure to ultraviolet light on disease severity by measuring national hospital IBD-related discharge rates.</p><p>Methods</p><p>Utilizing the Nationwide Inpatient Sample (NIS), we identified all patients with IBD-related discharges from 2001–2007. Patients were included if they were discharged from states above the 40^th parallel (north) or at or below the 35^th parallel (south); and their discharge fell within the winter (January, February, and March) or summer (July, August, and September). Groups of patients were assessed comparing north to south within each season, and summer to winter within each region. UV index was recorded from the National Weather Service data and compared to monthly discharge rates.</p><p>Results</p><p>There was a consistent pattern of increased IBD-related hospitalization rates in northern states compared to southern states for both ulcerative colitis and Crohn’s disease. Differences in IBD-related hospitalization rates by season, however, were not uniform across the years studied. UV index was significantly inversely associated although not proportional to discharge rates for both Crohn’s disease and ulcerative colitis.</p><p>Conclusions</p><p>In the US, there is a significant increased rate of IBD-related hospitalizations in the northern compared to southern states, which not fully explained by differences in UV exposure.</p></div

Multivariate analysis comparing south versus north.

<p>Variables included in the multivariate analysis included race, age, and payer status.</p

Discharge OR comparing seasons within each region as well as geography within each season.

<p>For each year, the OR were calculated for all IBD, UC only, and CD only.</p

Monthly discharge rates with associated mean UV index values for 2001–2004 for included northern and southern states.

<p>(a) Discharge rates for all IBD (p<0.001), (b) discharge rates for UC only (p<0.001), (c) discharge rates for CD only (p = 0.018).</p

Factors associated with readmission to the hospital within 30 days in patients with inflammatory bowel disease

<div><p>Background</p><p>Management of inpatients with inflammatory bowel disease (IBD) requires increasing resources. We aimed to identify factors associated with hospital readmissions among individuals with IBD.</p><p>Materials & methods</p><p>We collected data from the Healthcare Cost and Utilization Project Nationwide Readmissions Database 2013. We identified individuals with index hospitalizations for IBD. Patient-specific factors, comorbidities and hospitalization characteristics were extracted for the index hospitalization. We performed logistic regression modeling to create adjusted odds ratios (ORs) for 30-day hospital readmission. Subgroup analysis was performed based on disease type and performance of surgery.</p><p>Results</p><p>We analyzed a total of 55,942 index hospital discharges; 3037 patients (7.0%) were readmitted to the hospital within 30 days. Increasing patient age (> 65: OR: 0.45; 95% CI 0.39–0.53) was associated with a decreased risk of readmission, while a diagnosis of Crohn’s disease (OR: 1.09; 95% CI 1.00–1.18) and male sex (OR: 1.16; 95% CI 1.07–1.25) were associated with an increased risk of readmission. The comorbidities of smoking (OR: 1.09; 95% CI 1.00–1.19), anxiety (OR: 1.17; 95% CI 1.01–1.36) and opioid dependence (OR: 1.40; 95% CI 1.06–1.86) were associated with an increased risk of 30-day readmission. Individual hospitalization characteristics and disease complications were significantly associated with readmission. Performance of a surgery during the index admission was associated with a decreased risk of readmission (OR: 0.57; 95% CI 0.33–0.96).</p><p>Conclusion</p><p>Analyzing data from a US publicly available all-payer inpatient healthcare database, we identified patient and hospitalization risk factors associated with 30-day readmission. Identifying patients at high risk for readmission may allow for interventions during or after the index hospitalization to decrease this risk.</p></div

Cumulative incidence of readmission for IBD, CD and UC.

<p>(y-axis: percent of readmission when compared to the total population).</p

Demographic, patient and hospital characteristics.

<p>Demographic, patient and hospital characteristics.</p

Forest plot of significant factors on multivariate analysis for 30-day readmission among individuals with Crohn’s disease.

<p>Forest plot of significant factors on multivariate analysis for 30-day readmission among individuals with Crohn’s disease.</p

IBD risk factors for 30-day readmission.

<p>IBD risk factors for 30-day readmission.</p