Outside Facility Transfer Is Associated With Frequent Disposition to Rehabilitation Following Transcatheter Aortic Valve Replacement

Division of Cardiac Surgery, Brigham and Women’s Hospital; Harvard Medical School, Boston, MA, USA

*Corresponding author: Tsuyoshi Kaneko, Division of Cardiac Surgery, Brigham and Women’s Hospital, 15 Francis St, Boston MA, 02115, USA.

# Hirji SA, Shah RM contributed equally.

Received: November 11, 2019 Published: November 28, 2019

ABSTRACT

Introduction: Significant variability exists in disposition practices to non-home facilities following transcatheter aortic valve replacement (TAVR). Increased spending due to Post Acute Care Transfer (PACT) policies has led hospitals to scrutinize patient disposition following hospital discharge. We sought to examine the impact of admission origin on rehabilitative services use following TAVR.

Methods: The National Inpatient Sample was queried for TAVR procedures between 2012-2014. We further isolated patients who were discharged to a rehabilitation facility (skilled nursing facility, intermediate care facility, or other rehabilitation facility) stratified by admission origin. Multivariable logistic regression was used to determine independent predictors for disposition to a rehabilitation facility.

Results: A total of 12,175 TAVR patients were discharged to rehabilitation facilities. This included 10,520 patients (86.4%) who were admitted from home, 1,255 patients (10.3%) who were transferred from an acute care hospital, and 355 patients (2.9%) who were transferred from another health facility at the time of admission. Patients transferred from an acute hospital had higher inpatient costs ($77,092 vs. $66,507 and $64,861) and longer length of stay (17.2 vs. 11.6 and 10.6 days; all p < 0.05) compared to those transferred from a non-acute facility and those not transferred, respectively. Weekend admission (odds ratio [OR]= 1.78, 95% confidence interval [CI]: 1.11 to 2.84; p=0.017), non-elective admission (OR= 8.23, 95% CI: 4.15 to 13.16; p<0.001), and transfer from a non-acute facility (OR 4.32, 95% CI: 1.74 to 10.67; p=0.002) were independent predictors for disposition to a rehabilitation facility.

Conclusions: Admission origin appears to impact the likelihood of requiring rehabilitation services following TAVR, independent of academic status and patient comorbidities. Drivers propagating non-home discharge, such as weekend transfers from non-acute facilities and non-elective cases, should be investigated to optimize hospital resource utilization under current PACT policies.

Keywords: Transcatheter Aortic Valve Replacement; Post-Acute Care Transfer; Aortic Valve Treatment; Surgical Aortic Valve Replacement.

INTRODUCTION

Transcatheter aortic valve replacement (TAVR) has emerged as an established treatment option for the management of symptomatic severe aortic stenosis in in-operable, highrisk, and intermediate-risk patients [1-3]. Given the inherent medical complexity of this patient population, unplanned 30- day readmission rates are frequent (ranging from 14-21%) and have been shown to contribute negatively towards patient outcomes and healthcare costs [4-6]. Furthermore, the majority of readmissions after TAVR are often secondary to non-cardiac etiologies, including respiratory failure, infection and bleeding [7].

In light of the significant burden associated with readmissions following TAVR, heightened attention has been focused on analyzing risk factors for readmission at hospital, state and federal levels. In fact, 30-day readmission rates is an established quality performance metric per the Centers for Medicare and Medicaid services (CMS). Consequently, there are several ongoing efforts to develop novel strategies for reducing readmissions [8]. A specific focus involves efforts to increase discharges to home versus rehabilitation facilities such as skilled nursing facilities (SNF), whenever possible.

The implications of discharge destination have been described in prior studies and are significant for both clinical and economic reasons; in particular, discharge to SNF is an independent predictor of 30-day readmission [4]. Moreover, increased spending due to Post Acute Care Transfer (PACT) policies has led hospitals to scrutinize patient disposition following discharge. However, significant variability exists in disposition practices to non-home facilities following TAVR [9,10]. While patient-related and hospital-based risk factors for non-home discharge are established, the impact of origin of admission on ultimate disposition remains unknown, but is relevant in understanding pre-hospital drivers that predict post-TAVR disposition. In this study, we sought to examine the impact of admission origin on use of rehabilitative services following TAVR.

METHODS

Data Source

The National Inpatient Sample (NIS) is derived from the Healthcare Utilization Project and is the largest inpatient, publicly-available, all-payer database based on administrative claims [11]. The repository consists of a 20% sample of de-identified information on patient demographics, comorbidities, in-hospital outcomes including length of stay (LOS), costs, and discharge disposition from approximately 1,000 non-federal hospitals. When nationally weighted, the data represent more than 35 million discharges annually.

Study Population and Outcomes

We retrospectively identified all TAVR discharges using International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) procedures codes between 2012- 2014. We further isolated patients who were discharged to a rehabilitation facility (the rehab cohort - SNF, intermediate care facility (ICF) or any other rehabilitative facility) following their TAVR procedure (Supplement Table 1). We excluded all patients who underwent both surgical aortic valve replacement (SAVR) and TAVR during the same hospitalization.

Our primary outcome of interest was disposition tendency to a rehabilitation facility. Secondary outcomes were inpatient costs, LOS and in-hospital outcomes: complete heart block, cardiogenic shock and cardiac arrest. Elixhauser comorbidities, which are a common measure of comprehensive comorbidities for large administrative inpatient databases, were utilized as single categories and as an index to serve indirectly as an indicator for frailty [12,13]. The Charlson Comorbidity Index, which was calculated using ICD-9-CM codes, was used to summarize the comorbidity burden for an individual [14]. Hospital-specific variables such as hospital size, location, teaching status, region and ownership were also queried.

Statistical Methods

Survey procedures were applied to (1) generate national estimates and variances using given probability weights and (2) to account for clustering of outcomes by sampling unit (i.e. hospital) and sampling variation by region and year, as described previously [15,16]. Differences in patient demographics, comorbidities, in-hospital and hospital-level factors between the rehab cohort versus home discharge cohort were compared using univariate analysis. Costs were calculated using hospital charges and cost-to-charge ratios in US dollars [17]. Within the rehab cohort, we further compared preoperative, in-hospital, and hospital-level factors by admission origin. The 3 comparison groups were (1) not transferred (i.e. coming from home) (2) transferred from acute care hospital and (3) transferred from another health facility.

Continuous variables are expressed as a mean with standard deviation and were compared using Generalized Wald tests. Categorical variables are presented as number and percentages and were compared using Chi-squared tests. We also developed a stepwise, backward-selection, multivariable logistic regression model to determine independent predictors for disposition to a rehabilitation facility following TAVR. Covariates with a p-value <0.05 were kept in the model; those that crossed this threshold were manually trimmed in the final iteration of the model until all remaining covariates met the significance level. These results are presented as odds ratios (OR) and 95% confidence intervals (CI). All analyses were conducted using STATA Version 13.1 (StataCorp LP, College Station, TX) survey procedures with an alpha level of p ≤0.05 as the criterion for significance.

RESULTS

Characteristics and Outcomes Stratified by Discharge Disposition

A total of 40,900 patients met inclusion criteria. Of these, 12,175 patients were discharged to a rehabilitation facility (i.e. the rehab cohort; Table 1). The rehab cohort was significantly older, more likely female, and had a higher number of chronic conditions (such as atrial fibrillation, prior pacemaker placement, renal failure) compared to the home discharge cohort (all p <0.001). These patients were also less likely to be admitted electively and more likely to be transferred in preoperatively (13.3% vs. 4.4%; p <0.001). Proportionally, more patients in the rehab cohort underwent the trans-apical TAVR approach (26.6% vs. 14.4%, p <0.01) compared to the home discharge cohort.

In terms of postoperative outcomes, the rehab cohort had a higher incidence of complete heart block, cardiogenic shock and cardiac arrest, and significantly longer inpatient LOS and costs compared to the home discharge cohort (all p <0.01; Table 1). After stratifying the cohort by admission origin, TAVR patients who were transferred from another health facility or an acute care facility had significantly higher proportions of discharges to rehabilitation facilities postoperatively compared to patients not transferred (80.7% and 70.7% vs. 44.5%; all p <0.01; Figure 1)

Table 1: Preoperative Factors, Hospital Characteristics, and In-Hospital Outcomes of TAVR Patients Stratified by Discharge Disposition.

Figure 1: Proportion of Discharges to Rehabilitation Facilities Following TAVR by Preoperative Admission Origin.

Characteristics and Outcomes of Rehab Cohort Stratified By Admission Origin

Of the 12,175 patients in the rehab cohort, 10,520 patients (86.4%) were admitted from home, 1,255 patients (10.3%) were transferred from an acute care hospital, and 355 patients (2.9%) were transferred from another health facility (Table 2). In general, patient age, sex, and comorbidity profile of patients did not vary by admission origin (all p >0.05). But patients who were transferred from an acute care hospital were more likely to be admitted over the weekend compared to patients who were not transferred (17.9% vs 5.4%; global p <0.01).

Although major in-hospital cardiac complications and other hospital-level factors did not vary by admission origin (all p >0.05), patients who were transferred from acute care hospital had significantly longer LOS (17.2 vs 10.6 days and 11.6 days; p <0.01) and higher admission costs ($77,092 vs $64,861 and $66,507; p <0.01) compared to those not transferred and those transferred from another facility, respectively.

Table 2: Preoperative Factors, Hospital Characteristics, and In-Hospital Outcomes of TAVR Rehab Cohort Stratified by Admission Origin.

Predictors of Disposition to a Rehabilitation Facility

In our final multivariable regression model, admission day on weekend (OR 1.78, 95% CI: 1.11 to 2.84), non-elective admission (OR 8.23, 95% CI: 4.15 to 13.16) and patient residency/occupancy in a micropolitan county (OR 2.57, 95% CI: 1.41 to 4.65), were independent predictors of disposition to a rehabilitation facility (all p <0.05; Table 3). Most notably, transfer from another type of health care facility was also found to be associated with increased risk for disposition to a rehabilitation facility after discharge (OR 4.32, 95% CI: 1.75 to 10.67). However, hospital academic status, patient comorbidities and transfer from an acute care facility did not impact the likelihood of discharge to a rehabilitation facility after TAVR.

Table 3: Independent Predictors for Postoperative Disposition to a Rehabilitation Facility Following TAVR.