Temporal Trend in Hospitalization Among Patients With Congenital Heart Disease: A Danish Nationwide Study

Abstract

Background: The congenital heart disease (CHD) population is growing and aging. We aim to examine the impact by describing the temporal trend and causes of lifetime hospitalization burden among the CHD population.

Methods and results: From the Danish National Patient Registry, 23 141 patients with CHD and their hospitalizations from 1977 to 2018 were identified, excluding patients with extracardiac malformation. Patients with CHD were categorized into major CHD and minor CHD, and each patient was matched with 10 controls by sex and year of birth. The rate of all-cause hospitalization increased over time from 28.3 to 36.4 hospitalizations per 100 person-years (PY) with rate difference (RD) per decade of 2.5 (95% CI, 2.0-3.1) hospitalizations per 100 PY for the patients with CHD, compared with the increase from 10.8 to 17.0 per 100 PY (RD per decade, 2.0 [95% CI, 1.8-2.2] per 100 PY) for the control group (RD for CHD versus control, P=0.08). The all-cause hospitalization rate remained constant for the major CHDs (RD per decade, -0.2 [95% CI, -1.2 to 0.9] per 100 PY) but increased for the minor CHDs (RD per decade, 5.2 [95% CI, 4.3-6.0] per 100 PY). For all patients with CHD, the cardiovascular hospitalization rate remained constant over time (RD per decade, 0.2 [95% CI, -0.3 to 0.6] per 100 PY) whereas the noncardiovascular hospitalization rate increased (RD per decade, 2.1 [95% CI, 1.6-2.7] per 100 PY). The length of all-cause hospital stays for all patients with CHD decreased from 2.7 (95% CI, 2.6-2.8) days per PY in 1977 to 1987 to 1.6 (95% CI, 1.6-1.7) days per PY in 2008 to 2018.

Conclusions: Compared with previous decades, patients with CHD have an increasing hospitalization rate, similar to the general population, but a decreasing length of hospital stay. The increase in hospitalization rate was driven by noncardiovascular hospitalizations, with the patients with minor CHD being the key contributor to the increasing rate.

Keywords: all‐cause hospitalization rate; cardiovascular hospitalization; congenital heart disease; length of hospital stay; noncardiovascular hospitalization; temporal trend.

Figure 1. Flowchart.

Flow chart depicting study sampling, inclusion, and exclusion of cases and controls from the Danish nationwide registries. Controls were identified from the Danish Civil Registration System and matched with the individual patient with CHD by sex and year of birth at ratio of 10:1. AoS indicates congenital aortic stenosis; ASD, atrial septal defect; AVSD, atrioventricular septal defect; AV valve, atrioventricular valve anomalies; CHD, congenital heart disease; CoA, coarctation of the aorta; DNPR, Danish National Patient Registry; D‐TGA, transposition of the great arteries; PA, pulmonary atresia; PDA, patent ductus arteriosus; PFO, patent foramen ovale; PS, congenital pulmonary stenosis; SV, single ventricle; ToF, tetralogy of Fallot; and VSD, ventricular septal defect.

Figure 2. Temporal trend in hospitalization rate stratified by CHD subgroups and causes of hospitalization.

A, All‐cause hospitalization rate for all patients with CHD vs controls. B, All‐cause hospitalization rate for patients with major CHD and patients with minor CHD vs their respective matched controls. C, Cardiovascular and noncardiovascular hospitalization rate for all patients with CHD vs controls. CHD indicates congenital heart disease; PY, person‐year; and RD, rate difference in hospitalization rate.

Figure 3. Temporal trend in cardiovascular hospitalization rate, stratified by disease complexity and age group.

The total height of the bar depicts the mean hospitalization rate per 100 person‐years for all cardiovascular hospitalization for respective decade, with the P values indicating the significance of the temporal trend in the cardiovascular hospitalization rate, obtained from negative binomial regression model. Segments in the bar represents the cause‐specific mean hospitalization rate for the most common causes of cardiovascular hospitalization. CHD indicates congenital heart disease; CV, cardiovascular; GLM, general linear model; and IHD, ischemic heart disease.

Figure 4. Temporal trend in noncardiovascular hospitalization rate, stratified by disease complexity and age group.

The total height of the bar depicts the mean hospitalization rate per 100 person‐years for all noncardiovascular hospitalization for respective decade, with the P values indicating the significance of temporal trend in the noncardiovascular hospitalization rate, obtained from negative binomial regression model. Segments in the bar represents the cause‐specific mean hospitalization rate for the most common causes of noncardiovascular hospitalization. CHD indicates congenital heart disease; CV, cardiovascular; and GLM, general linear model.