Comorbidity in Mississippi Patients Hospitalized with Diabetes: The Use of Hospital Discharge Data for Conducting Evidence-Based, Population-Level Research

Background: From 1996-2011, the prevalence of diabetes in Mississippi increased from 6.3% to 11.6%. While patients with diabetes are at increased risk for comorbidity, few data sources are available for evaluating the number and severity of co-existing conditions. Using Mississippi hospital discharge data, the purpose of this study was to evaluate the comorbidity burden and patterns among patients hospitalized with a diagnosis of diabetes in Mississippi.

Methods: We analyzed Mississippi hospital discharge data for 2011 with SAS 9.3. For calculating the weighted scores and number of comorbidities, we implemented the Charlson/Deyo Comorbidity Index, a risk adjustment algorithm based on seventeen chronic conditions. Each condition is assigned a score (weight) from 1 to 6 that is proportional to the severity of the illness. We conducted comparative analyses of hospitalizations for diabetes and hospitalizations without diabetes using chi-square tests and t-tests. The study included only Mississippi residents with a primary or secondary diagnosis of diabetes.

Results:  In 2011, there were 84,649 diabetes-related hospitalizations, accounting for 22% of all hospitalizations among state residents. The hospitalization rate was 28 diabetic patients per 1,000 residents. The mean Charlson/Deyo comorbidity score was 1.2 for hospitalized patients with diabetes and 0.7 for those without diabetes (p < 0.001). The results of the bivariate analyses revealed that compared to all other hospitalizations, patients with diabetes were more likely to have a comorbidity score ≥ 1 (58% vs. 31%, p < 0.001). Diabetic patients were also more likely to have high comorbidity scores: 16% of patients with diabetes had a comorbidity score ≥ 3 (vs. 8% for patients without diabetes, p < 0.001). Congestive heart failure (23%), chronic pulmonary disease (21%), chronic renal disease (20%), cerebrovascular disease (10%), and old/acute myocardial infarctions (8%) were the five leading comorbidities among patients with diabetes.

Conclusion:  During 2011 over one in five hospitalizations was related to diabetes in Mississippi and diabetes was associated with high comorbidity burden. Underscoring the utility of hospital discharge data for evidence-based research, these findings can help policy makers and public health programs in their evaluation of the diabetes epidemic and its impact on the overall population’s health.