Causes of Readmissions and Their Avoidability for the Most Common Comorbidities

Background:

Readmissions to the hospital are costly and sometimes avoidable. A better understanding of the reasons for readmission among different patient populations (e.g., those with different chronic conditions) may lead to more targeted and successful interventions. We aim to describe the proportion and pattern of 30‐day readmissions and potentially avoidable readmissions (PAR) of medical patients according to the most common comorbidities.

Methods:

We included all consecutive discharges from any medical service of an academic tertiary medical center in Boston between July 1, 2009, and June 30, 2010. Potentially avoidable 30‐day readmissions to the index hospital or 2 other hospitals within its network were then identified using a validated computerized algorithm based on administrative data (SQLape®). Most common comorbidities were identified using ICD‐9 codes of the index admission. Main cause of readmission was based on patient diagnosis‐related groups (DRGs). For this analysis, we present the 5 most frequent causes of PAR overall and for each comorbidity separately. We also compared the proportion of readmissions deemed potentially avoidable for patients discharged with and without each comorbidity using logistic regression. Proportions and their 95% confidence intervals were adjusted for length of stay, mode of admission (elective or not), number of admissions in the previous 12 months, number of procedures during the index admission, hemoglobin and sodium levels at discharge of index admission, and number of other comorbidities.

Results:

Among 10,731 discharges, 2398 (22.3%) were followed by a 30‐day readmission, of which 879 (8.5%) were identified as PAR. The top 5 causes of 30‐day PAR were infection, neoplasm, heart failure, gastrointestinal disorder, and liver disorder (Table 1). For most chronic conditions except neoplasm (diabetes, heart failure, ischemic heart disease, atrial fibrillation, and chronic kidney disease), the first 2 causes of PAR were heart failure (12.2%–25.5%) and infection (8.02%–11.5%). Only patients discharged with a diagnosis of diabetes or chronic kidney disease had a significantly higher proportion of readmissions deemed potentially avoidable than those without those comorbidities (Table 2).

Conclusions:

Interestingly, this study shows that patients with diabetes or chronic kidney disease have a higher proportion of potentially avoidable readmission than patients without each of these comorbidities. The main causes of PAR for most of the common comorbidities are heart failure and infection. Together, these findings may help hospitals target interventions to populations most likely to benefit from them.