Trends and Outcomes of Pulmonary Arterial Hypertension-Related Hospitalizations in the United States: Analysis of the Nationwide Inpatient Sample Database From 2001 Through 2012

Abstract

Importance: Recent trends and outcomes of pulmonary arterial hypertension (PAH)-related hospitalization in adults in the United States are unknown.

Objective: To examine the characteristics of PAH-related hospitalizations.

Design, setting, and participants: We analyzed the National Inpatient Sample database for all adult patients (≥18 years old) with PAH as the principal discharge diagnosis from January 1, 2001, through December 31, 2012.

Main outcomes and measures: We analyzed the temporal trends in hospitalization rate, hospital charges, in-hospital mortality, length of hospitalization, and comorbidities pertaining to PAH-related hospitalizations. We also evaluated the predictors of in-hospital mortality and length of hospitalizations.

Results: The number of PAH-related hospitalizations per year in adults decreased significantly from 2001 through 2012 (3177 vs 1345, P for trend <.001). However, the mean hospital charge per admission increased 2.7-fold from 2001 through 2012 ($29 507 vs $79 607, P for trend <.001). There was a significant increase in each of these associated comorbid conditions: diabetes (4.6%-7.8%), hypertension (5.1%-17.1%), coronary artery disease (15.6%-22.3%), chronic obstructive pulmonary disease (14.4%-20.1%), anemia (12.4%-20.4%), cardiac dysrhythmias (21.7%-29.0%), congestive heart failure (40.7%-56.1%), acute (5.9%-20.1%) or chronic kidney disease (1.1%-16.4%), fluid and electrolyte imbalance (18.9%-35.3%), pneumonia (4.4%-6.3%), cardiogenic shock (0.5%-1.5%), and acute respiratory failure (4.3%-20.8%) from 2001 through 2012. The length of hospitalization increased (mean [SE], 7.0 [0.5] days in 2001 vs 7.6 [0.6] days in 2012, P for trend = .009), but in-patient mortality remained unchanged (7.8% [1.1%] in 2001 vs 6.3% [1.7%] in 2012, P for trend = .54). Admission to a teaching hospital (β coefficient for length of hospitalization, 2.0; 95% CI, 1.3-1.6; odds ratio [OR] for mortality, 1.5; 95% CI, 1.1-2.1), cardiac dysrhythmias (β coefficient, 1.8; 95% CI, 1.1-2.6; OR, 1.8; 95% CI, 1.4-2.4), acute kidney injury (β coefficient, 5.0; 95% CI, 3.9-6.1; OR, 2.3; 95% CI, 1.7-3.2), acute cerebrovascular accident (β coefficient, 6.6; 95% CI, 1.9-11.3; OR, 6.7; 95% CI, 2.1-21.1), and acute respiratory failure (β coefficient, 6.2; 95% CI, 5.1-7.4; OR, 5.6; 95% CI, 4.2-7.5) were associated with increased length of hospitalization and in-hospital mortality. Congestive heart failure (OR, 1.7; 95% CI, 1.3-2.2), cardiogenic shock (OR, 5.4; 95% CI, 2.7-10.9), and fluid and electrolyte imbalance (OR, 1.9; 95% CI, 1.5-2.4) were associated with increased in-hospital mortality but not length of hospitalization.

Conclusions and relevance: Analyses of temporal changes in PAH care reveal a significant decrease in PAH-related hospitalizations in the United States, but hospital charges have increased substantially and are increasingly being borne by Medicare. In-hospital mortality remains unchanged, but length of hospitalization has increased. This study should help identify the characteristics of patients with PAH that are associated with increased risk of in-hospital mortality and longer length of hospitalization.

Figure 1. The Number of Hospital Discharges and the Mean Charges of Hospital Stay for Principal Diagnosis of PAH between 2001 and 2012

The PAH related hospitalizations have decreased significantly from 3177 in 2001 to 1345 in 2012, p for trend <0.001 (red) and the mean charges for PAH-related hospitalizations have increased significantly from $29507 in 2001 to $79607 in 2012, p for trend <0.001 (blue). PAH indicates Pulmonary Arterial Hypertension. The arrows indicate the year of FDA approval of PAH-specific therapies.

Figure 2. Trend in In-hospital Mortality (A) and Length of Stay (B) of PAH-related Hospitalizations between 2001 and 2012

There was no significant difference in the in-hospital mortality of patients hospitalized with PAH from 2001 to 2012 (p for trend =0.54) (A). However, the average length of hospital stay increased from 7.0 ± 0.5 days in 2001 to 7.6 ± 0.6 in 2012, p for trend=0.009 (B).