30 Day Readmissions in Patients with Pulmonary Embolism in the United States

Introduction: Pulmonary Embolism (PE) is an important cause of the morbidity and mortality in the United States (US). National estimates of 30-day readmissions in PE patients in the US are unknown. The objective of our study was to estimate readmission rates and identify causes, predictors and cost of readmissions in PE patients.

Methods: We used National Readmission Dataset (NRD - the year 2013), Healthcare Cost and Utilization Project (HCUP), Agency for Healthcare Research and Quality which represents one of the largest random sample of discharges from all hospitals, excluding rehabilitation and long-term acute care hospitals. NRD is designed to generate the national estimates of readmission analysis. NRD contains approximately unweighted 14 million discharges and weighted 36 million discharges. Discharge weights were utilized to generate the national estimates. The patients with PE were identified by primary discharge diagnosis with ICD9-CM code 415.1. All cause unplanned 30-day readmission rates were calculated for patients admitted between January and November 2013 by excluding elective readmissions. Deyo's modification of Charlson comorbidity index was used to define the severity of co-morbid conditions. Using SAS version 9.3, survey procedures were implemented to adjust for stratified cluster design of NRD with DOMAIN, STRATA, CLUSTER and WEIGHT statement. A p-value of less than 0.05 was considered significant. The independent predictors of unplanned 30-day readmissions were identified by logistic regression. The cost of readmission was calculated by multiplying total charges with the cost to charge ratio provided by HCUP.

Results: The NRD contained 73,754 unique PE patients with 141,678 admissions (weighted N = 332,736) in 2013. After excluding elective readmissions, all cause 30-day readmission rate was 12.8%. The top causes of unplanned readmissions were pulmonary heart disease (11.1%), septicemia (6.6%), pneumonia (5.4%), congestive heart failure (4.4%), phlebitis (3.3%), gastrointestinal hemorrhage (3.1%), nonspecific chest pain (2.6%), respiratory failure (2.6%), cardiac dysrhythmias (2.5%), COPD and bronchiectasis (2.4%). The multivariate predictors for higher 30 day unplanned readmissions were Charlson comorbidity index (OR 1.13, p<0.0001), large bedside hospitals (OR 1.2, p<0.0001), metropolitan teaching hospitals (OR 1.14, p<0.0001), Medicaid payer (OR 1.37, p<0.0001), discharge on home health care (OR 1.45, p<0.0001), discharge against medical advice (OR 3.49, p<0.0001), any bleeding complications (OR 1.17, p=0.003), congestive heart failure (OR 1.51, p<0.0001), chronic pulmonary disease (OR 1.49, p<0.0001), cancer (OR 1.81, p<0.0001), operating room procedures (OR 1.48, p<0.0001), and septic shock (OR 1.27, p<0.0001). The multivariate predictors for lower 30 day unplanned readmissions were higher age (OR 0.99, p<0.0001), non-metropolitan hospitals (OR 0.84, p<0.0001), elective admission (OR 0.81, p=0.015), private payer including HMO (health maintenance organization) (OR 0.73, p<0.0001), saddle PE (OR 0.65, p<0.0001), and thrombolysis (OR 0.77, p=0.002). The estimated total cost of unplanned 30-day readmissions in PE patients was $1.02 billion for 2013.

Conclusions: The unplanned 30-day readmission rates and the cost are high in PE patients in the US. Further research is needed to identify preventable readmissions, strategies to cut down the readmissions and eventually reduce the cost of readmissions in patients admitted with PE.