In the adult congenital heart disease (ACHD) population, pulmonary valve replacement (PVR) is a common intervention, its benefit, however, has been incompletely investigated. This study investigates short- and intermediate-term outcomes after PVR in ACHD. Using State Inpatient Databases from the Healthcare Cost and Utilization Project, we investigated both hospitalization rate and financial burden accrued over the 12-month period after PVR compared with the 12 months before. Among 202 patients who underwent PVR, per patient-year hospitalization rates doubled in the year after PVR compared with the year before (0.16 vs 0.36, p = 0.006). With the exception of postprocedural complications, the most common reasons for hospitalization were unchanged after surgery: 22% of patients were admitted with equal or greater frequency after PVR. These patients experienced higher inpatient costs both at index admission and in the year after PVR (p = 0.004 and p <0.001, respectively). Univariate predictors of increased hospitalizations after PVR were age ≥50 years (p = 0.016), transposition of the great arteries, or conotruncal abnormalities (p <0.001), lipid disorders (p = 0.025), hypertension (p = 0.033), and number of chronic conditions ≥4 (p = 0.004). Multivariate analysis identified transposition of the great arteries or conotruncal abnormalities as an independent risk factor for increased hospitalization and cost post-PVR (p ≤0.001). In conclusion, short-term costs and hospitalization rates increase after PVR in a small group of patients with ACHD.
The number of adults with congenital heart disease (ACHD) is rapidly rising. Many of the cardiac repairs performed during childhood deteriorate with the passage of time, making reoperation common in patients with ACHD. These repeat operations are a source of significant morbidity and cost. Among the repeat operations performed, pulmonary valve replacement (PVR) is particularly common for both pulmonary valve insufficiency (PI) and for pulmonary valve or right ventricular to pulmonary arterial conduit stenosis. Chronic right ventricular volume or pressure overload is not benign and results in right ventricular dilation and dysfunction, impaired exercise tolerance, and a propensity to ventricular arrhythmia and sudden cardiac death. Despite this, identification of the patients most likely to benefit from and the optimal timing for PVR remain unclear. As the cost of caring for patients with ACHD continues to increase, it is becoming more important to identify care strategies that improve quality and efficiency. In this study, we investigated outcomes in the first year after PVR with the goal of identifying clinical variables associated with increased rates of hospitalization and cost.
Methods
For this analysis, we used the State Inpatient Databases (SIDs) from the Healthcare Cost and Utilization Project. We specifically used the SIDs for Arkansas (2008 to 2010), California (2003 to 2012), Florida (2005 to 2012), Hawaii (2006 to 2010), Nebraska (2003 to 2011), and New York (2005 to 2012). We selected these SIDs because they uniquely track hospitalizations in individual patients longitudinally, whereas other states track hospitalizations without tracking patients. The dates used were the most complete and up to date available at the time of analysis in April 2015. The primary outcomes were hospitalization rate and cost of inpatient care in the 12 months before compared with after PVR. The present study was approved by the Institutional Review Board at Washington University School of Medicine.
We first identified patients in the databases with ACHD by selecting patients in the SIDs with an age of greater than 18 years and with a 3-digit International Statistical Classification of Diseases and Related Health Problems (ICD-9) diagnosis code of 745, 746, or 747 ( Figure 1 ). To this group of patients, we applied a validated hierarchical algorithm described by Broberg et al to categorize patients based on anatomy. Any patients who failed to be classified according to this algorithm were excluded to increase the probability that all the patients included for analysis in fact had ACHD.
We next identified patients with a hospitalization specifically for PVR during the follow-up period. We identified these hospitalizations by selecting those for which there was both a major operating room procedure flag and who had an ICD-9 4-digit diagnosis code of 3525, 3526, 3592, or 3507 ( Figure 1 ). We excluded patients with hospitalizations for PVR within the first or last 12 months of the investigated period, so that we were certain a full 12 months of data were present before PVR, and a full 12 months of follow-up after PVR were available for every patient. We excluded all patients who had an ICD-9 code for any other cardiac operation at the time of PVR with the goal of identifying admissions specifically for PVR.
Rates of hospitalization and cost of inpatient care in the 12 months before and after PVR were then compared with a Poisson model using generalized estimating equation methods. Generalized estimating equation methods were used to handle repeated-measures data given multiple periods, for example, pre- and post-PVR. Models were scaled using Pearson correlations to adjust for overdispersion. Inpatient care costs for the 12 months before PVR were adjusted for inflation to reflect October 2015 dollars based on the consumer price index of medical care. The top 6 primary admitting diagnosis codes within 12 months before and after index PVR were compared using the McNemar’s test. Patients who died during the hospitalization for PVR were excluded.
To identify variables associated with suboptimal outcomes in the first year after PVR, we defined 2 groups of patients. Patients who had fewer hospitalizations in the 12 months after PVR than before or who had no hospitalizations during either period were defined as group A. Those with a greater number of hospitalizations in the 12 months after PVR than before or who had the same, nonzero number of hospitalizations during both periods were defined as group B. Patients who died during index hospitalization were defined as group B. Patient data were summarized overall and by group A versus B. Comparisons between groups A and B were done using the Mann–Whitney U test for continuous variables and Fisher’s exact test or Pearson chi-square test for categorical variables. Continuous variables were summarized using the median (first quartile and third quartile) and categorical variables were summarized using counts (percents). Hospitalization cost in the 12 months after PVR was subtracted from that in the 12 months before PVR to compare the differences in cost between groups A and B based on the previously mentioned definition. These cost differences were then compared using the Mann–Whitney U test. PVR reason was defined as “PI” if an admitting diagnosis code for index PVR hospitalization was ICD-9 = 746.09 or “pulmonary arterial conduit stenosis” if ICD-9 = 746.02. Patients having both ICD-9 codes were classified as “PI.”
A multivariable logistic regression model was then built to examine independent predictors for being in group B. Based on subject knowledge and after examining univariate associations, the following variables were included: age, transposition of the great arteries (TGA)/conotruncal abnormalities, number of chronic conditions, and arrhythmia. Age and number of chronic conditions were dichotomized (age <50 vs ≥50 years; number of chronic conditions <4 vs ≥4) for this model. Odds ratios, 95% CIs, and p values were reported from the model results.
All analysis conducted in SAS, version 9.4 (SAS Institute Inc., Cary, North Carolina).
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