Orthopedics

Feature Article Supplemental Data

Outpatient Versus Rapid Recovery Inpatient Knee Arthroplasty: Comparison of Matched Cohorts

Chloe C. Kimball, BA; Christine I. Nichols, MA, MBA; Joshua G. Vose, MD, MBA

Abstract

Increased focus on reducing the cost of total knee arthroplasty (TKA) has driven greater interest in performing the procedure in an outpatient setting. This study used exact matching to compare clinical and economic outcomes following TKA in an outpatient vs rapid recovery inpatient setting. This study used a nationally representative commercial database. Patients were grouped into 2 cohorts: same-day outpatient TKA (surgery center or hospital outpatient) or short-stay inpatient TKA (“rapid recovery”; length of stay 1 day or less). Only patients discharged home under self-care or with health care were included. Exact 1:1 matching was performed on clinical and demographic characteristics to control for potential case-selection bias by choice of care setting. Prior to matching, 969 outpatients and 8101 rapid recovery inpatients met selection criteria. The outpatient cohort was younger (median age, 58 vs 61 years), predominantly female (56% vs 51%), and less comorbid (Charlson Score of 0: 84.2% vs 74.0%) vs the rapid recovery cohort. Post-match, 863 patients were available in each cohort. The outpatient cohort exhibited a significantly lower incidence of opiate use (80.4% vs 90.7%; P<.001) and minor complications (2.8% vs 5.8%; P=.002). Incidence of major complications (5.2% vs 6.7%, P=.173) and 90-day readmissions (5.1% vs 7.3%, P=.064) were equivalent. The outpatient median 90-day episode payment was $6824 lower (22%) per patient ($24,749 vs $31,573, respectively; P<.001). This study suggests that among carefully selected patients undergoing outpatient TKA, outcomes are equivalent, if not improved, at a lower payor cost compared with a rapid recovery inpatient setting. [Orthopedics. 202x; 4x(x):xx–xx.]

Abstract

Increased focus on reducing the cost of total knee arthroplasty (TKA) has driven greater interest in performing the procedure in an outpatient setting. This study used exact matching to compare clinical and economic outcomes following TKA in an outpatient vs rapid recovery inpatient setting. This study used a nationally representative commercial database. Patients were grouped into 2 cohorts: same-day outpatient TKA (surgery center or hospital outpatient) or short-stay inpatient TKA (“rapid recovery”; length of stay 1 day or less). Only patients discharged home under self-care or with health care were included. Exact 1:1 matching was performed on clinical and demographic characteristics to control for potential case-selection bias by choice of care setting. Prior to matching, 969 outpatients and 8101 rapid recovery inpatients met selection criteria. The outpatient cohort was younger (median age, 58 vs 61 years), predominantly female (56% vs 51%), and less comorbid (Charlson Score of 0: 84.2% vs 74.0%) vs the rapid recovery cohort. Post-match, 863 patients were available in each cohort. The outpatient cohort exhibited a significantly lower incidence of opiate use (80.4% vs 90.7%; P<.001) and minor complications (2.8% vs 5.8%; P=.002). Incidence of major complications (5.2% vs 6.7%, P=.173) and 90-day readmissions (5.1% vs 7.3%, P=.064) were equivalent. The outpatient median 90-day episode payment was $6824 lower (22%) per patient ($24,749 vs $31,573, respectively; P<.001). This study suggests that among carefully selected patients undergoing outpatient TKA, outcomes are equivalent, if not improved, at a lower payor cost compared with a rapid recovery inpatient setting. [Orthopedics. 202x; 4x(x):xx–xx.]

Annual demand for total knee arthroplasty (TKA) is projected to grow to 3.48 million procedures by the year 2030.1 Effectively addressing this demand requires payors, providers, and policy makers to develop and implement solutions to reduce costs while either maintaining or improving the quality of care provided. Traditional efforts to reduce both payor and provider costs of total joint arthroplasty (TJA) have targeted reducing inpatient length of stay (LOS), incidence of major perioperative complications, and unnecessary readmissions. More recently, however, attention also has turned to shifting the location of care to ambulatory settings for carefully selected subgroups of patients.2

In response to the implementation of bundled payments and the movement of patients out of the inpatient setting, many hospitals have implemented new “rapid recovery” or “fast track” programs to further improve the average LOS from 3 days3–5 to as little as 1 day.6–10 These programs represent the middle ground between traditional inpatient and outpatient settings. However, the identification and management of specific risk factors—the principal challenge of safely shifting TKA patients to the out-patient setting—remains.11,12 Although there is research suggesting specific patient profiles that are most appropriate for out-patient TKA,8,9,11–16 there is little research describing the characteristics of current patients and their outcomes using a multi-center, nationally representative dataset.

The current study examined characteristics of patients who were discharged home after undergoing primary TKA in either an outpatient setting (outpatient hospital or surgical center) or a rapid recovery inpatient setting (defined as a length of stay of 1 day or less) and compared clinical and economic outcomes by setting among a matched subset of patients. Given the clinical protocols required to effectively discharge a patient home in under 24 hours should be similar regardless of the site of care, one would expect similar outcomes regardless of the site of care. If outcomes are similar in the group of patients deemed “eligible” for a rapid recovery protocol, it would follow that there is the potential for substantial cost savings to the US health system with a shift in the surgical setting. Therefore, the current study evaluated differences in outcomes and associated total payor costs attributed to procedure location among matched cohorts of patients discharged home with or without aid.

Materials and Methods

This study was a retrospective analysis of health care claims data from the Truven Health Analytics Marketscan Commercial Research Database (IBM Watson Health, Greenwood Village, Colorado) (2014–2015). The dataset contains more than 180 million unique patients covered with private insurance and Medicare Advantage, and provides nationally representative information on claims for outpatient and inpatient visits, prescription drug fills, demographics, location of service, and total health plan payments. The database is fully deidentified; therefore, this study did not require institutional review board approval.

Patient Selection

Patients selected for analysis were 18 years or older and were listed as having either an outpatient or inpatient visit with a primary International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) or International Classification of Diseases, Tenth Revision, Clinical Modification (ICD-10-CM) procedure code for unilateral TKA. Patients were grouped into 2 cohorts: same-day discharge outpatient TKA (performed in an outpatient hospital or ambulatory surgical center setting) or rapid recovery inpatient TKA (performed in an inpatient setting with the number of midnights less than or equal to 1). Patients were excluded from analysis if there was evidence of fracture of the lower limb or if the procedure was bilateral as indicated by Current Procedural Terminology code modifiers.

All patients were required to have continuous health insurance from baseline through the end of follow-up. Patients included both those with commercial-only coverage and those with Medicare Advantage plans. Finally, the study population was limited to patients discharged home under self-care or with home health care services. Patients discharged to post-acute care facilities were excluded to further attribute outcomes differences to the original surgical procedure location, rather than to differences in post-acute care received. The study baseline period was defined as 90 days prior to the index date (date of inpatient admission or outpatient procedure), and follow-up was defined as the day after discharge through 90 days.

Study Measures

Patient clinical histories were evaluated with ICD-9-CM or ICD-10-CM diagnoses codes listed during the baseline or index visit. In addition, the Charlson Comorbidity Index (CCI) score was calculated as an objective aggregate measure of patient comorbidity burden.17

Incidence of complications was evaluated during both the index visit and follow-up periods. Minor complications were defined as blood transfusion (autologous or allogeneic); hemorrhage, hematoma, or seroma (diagnosis complicating a procedure or a procedure for incision and drainage); wound disruption; or urinary tract infection. Major complications were defined as any infection (sepsis or septicemia, bacteremia, bone infection, or other postoperative infection), thromboembolic event (pulmonary, venous, and deep vein), renal failure, renal insufficiency, myocardial infarction, pneumonia, stroke or cerebrovascular accident, unplanned intubation, and reoperation. Implant-related complications included loosening, dislocation, implant failure, periprosthetic fracture, other mechanical complication of an internal orthopedic device (due to internal joint prosthesis, implant, or graft), or pain or stiffness in the joint. The incidence of all-cause readmissions, defined as any inpatient admission occurring during follow-up, also was analyzed.

Total health plan payments were summarized for the index visit and during the 90-day follow-up period. Payments were defined as all medical payments made for a patient, regardless of the site of care or the reason for the visit. All payments were inflation-adjusted to 2015 US dollars using the Medical Care component of the US Consumer Price Index. To address possible miscoding of payments, records with values listed as zero or above the 99th percentile were excluded from analyses.

Data Analysis

Due to the nonrandom assignment of patients to each cohort, exact matching was performed to minimize potential confounding effects and selection bias. Exact 1:1 matching allows examination of outcomes across comparable groups of patients to compare differences by procedure setting. Accordingly, each outpatient was matched with one rapid recovery in-patient. Matching covariates were selected based on measures that were significantly different (P<.05) in unmatched analysis and included age group, sex, census region, primary payor, CCI group, coronary artery disease, congestive heart failure, chronic obstructive pulmonary disease, diabetes, hypertension, sleep apnea, diagnosis of overweight or obesity, and history of smoking. In addition, patients were matched by procedure year.

Descriptive analyses were conducted for all study measures outlined above. Statistical significance testing was performed using the chi-square test for comparison of categorical variables and the Wilcoxon–Mann-Whitney test for comparison of continuous variables in unmatched analyses. In matched analyses, significance testing was performed using the McNemar test for categorical variables and the Wilcoxon–Mann-Whitney test for continuous variables.

Sample selection and the creation of analytic variables was performed using the Instant Health Data (IHD) platform (Boston Health Economics, Boston, Massachusetts). Statistical analyses were conducted using R version 3.2.1 software (R Foundation for Statistical Computing, Vienna, Austria) and SAS version 9.4 (SAS Institute Inc, Cary, North Carolina) software.

Results

Patient Demographics and Clinical History

Prior to matching, 969 patients were available for analysis in the outpatient cohort and 8101 patients were available in the rapid recovery inpatient cohort. After matching, 863 patients were assigned to each cohort for analysis.

Before matching, mean patient age was significantly lower in the outpatient cohort vs the rapid recovery inpatient cohort (57.2 vs 60.9 years, respectively), with a greater proportion of females in the outpatient cohort vs the rapid recovery inpatient cohort (56.4% vs 51%, respectively; P=.002) (Table A, available in the online version of this article).

Patient demographics and clinical characteristicsPatient demographics and clinical characteristicsPatient demographics and clinical characteristicsPatient demographics and clinical characteristics

Table A.

Patient demographics and clinical characteristics

The most common preoperative co-morbid diagnoses were hypertension (44.6% vs 60.6%), obesity (19.7% vs 25.6%), and diabetes without complications (11% vs 16.3%), all of which were significantly less prevalent in the outpatient cohort vs the rapid recovery inpatient cohort (all P<.001; Table B, available in the online version of this article). Following exact matching, all prior significantly different baseline demographic and clinical characteristics for both cohorts were well-balanced (all P>.05; Table A). In both matched cohorts, median age was 58 years, 56.8% were females, and 89.1% of patients had a CCI score of zero.

Co-Occurring comorbidities among unmatched outpatients

Table B.

Co-Occurring comorbidities among unmatched outpatients

Complications and Discharge Destination

In matched analysis, the incidence of minor complications was significantly lower for outpatients compared with rapid recovery inpatients (2.8% vs 5.8%, respectively; P=.002); the incidence of major complications was statistically equivalent (5.2% vs 6.7%; P=.173) (Table C, available in the online version of this article). Use of opiate pain medication was significantly lower in the outpatient cohort compared with the inpatient cohort (80.4% vs 90.7%, respectively; P<.001); this characteristic also was observed in the unmatched analysis. Almost all of the rapid recovery inpatients were discharged home under self-care (99.3%) compared with outpatients (94.6%), and the remaining 0.7% and 5.4%, respectively, were discharged home under care. Consistent with the unmatched analysis, use of physical therapy was statistically equivalent across both cohorts, with 86.2% of outpatients and 85.3% of rapid recovery patients having at least one kind of physical therapy during follow-up (P=.586).

Hospitalization characteristics and incidence of complications from day of admission through 90-day post-discharge follow-up periodHospitalization characteristics and incidence of complications from day of admission through 90-day post-discharge follow-up periodHospitalization characteristics and incidence of complications from day of admission through 90-day post-discharge follow-up period

Table C.

Hospitalization characteristics and incidence of complications from day of admission through 90-day post-discharge follow-up period

Readmissions

Across unmatched cohorts, the incidence of all-cause readmissions during the entire 90-day follow-up period was significantly lower among outpatients compared with rapid recovery inpatients (5.1% vs 6.9%; P=.041). Similarly, in matched analyses, the 90-day readmission rate was lower in the outpatient cohort than in the rapid recovery inpatients; however, the difference was not statistically significant (5.1% vs 7.3%; P=.064). Incidence of readmission during the first 30 days of follow-up also was statistically equivalent between matched cohorts (P=.157); however, readmissions were significantly lower in the outpatient cohort than in the rapid recovery inpatients during days 31 to 90 of follow-up (1.8% vs 5.1%, respectively; P<.001). When stratified by 5-day increments, incidence of readmission was numerically lower in the matched rapid recovery inpatient cohort relative to the outpatient cohort through day 45. Following day 45, an inflection point was observed, with the incidence of readmission remaining lower among the matched outpatient cohort through the end of follow-up (Figure 1).

Graph showing all-cause readmission following total knee arthroplasty, stratified by 5-day increments. *Significance testing included the chi-square test for unmatched and the McNemar test for matched cohorts.

Figure 1:

Graph showing all-cause readmission following total knee arthroplasty, stratified by 5-day increments. *Significance testing included the chi-square test for unmatched and the McNemar test for matched cohorts.

Medical Costs

In both unmatched and matched analysis, payments were lower among outpatients (Table D, available in the online version of this article). In matched analysis, the median index visit payment was $6880 (24.1%) lower in the outpatient setting than in the rapid recovery inpatient setting ($21,698 vs $28,578, respectively), and the median 90-day payment was $6824 lower in the outpatient setting than in the rapid recovery inpatient setting ($24,749 vs $31,573, respectively; P<.001).

Total health plan payments (USD)Total health plan payments (USD)

Table D.

Total health plan payments (USD)

Discussion

Given the national trend toward adoption of rapid recovery protocols and a shift to the outpatient setting for TKA procedures, it is critical to understand the value and impact of each setting, as well as the actual profiles of the patients. The current study of clinical and economic outcomes by setting with a nationally representative dataset expands on prior research by focusing on characteristics of outpatient TKA patients relative to those of rapid recovery inpatient programs. In addition, by controlling for the inherent case-selection bias in procedure location by using exact matching, the current study allowed for more accurate attribution of outcomes by procedure location.

As more TJA procedures are shifted to the outpatient setting, understanding the magnitude of risk associated with single and multiple comorbidities will be fundamental to optimize cost and outcomes. Prior research has demonstrated patients who are healthier, with no prior history of smoking, diabetes, hypertension, coronary artery disease, congestive heart failure, and chronic obstructive pulmonary disease, as well as those who are outside the clinical classification of obesity, are at the lowest risk of complications following TKA if surgery is shifted to an outpatient setting.8,11,14,16,18 Objectively, these patients may represent the ideal profile for providers to transition from a rapid recovery inpatient setting to an outpatient setting. Importantly, this population does not need to be in perfect health; more than half (51%) of the patients selected for the outpatient setting in the current study had at least 1 comorbidity compared with 78% in the rapid recovery cohort. In addition, there were relatively few patients with 2 or more major comorbidities in the outpatient cohort; the most common concurrent comorbidities were obesity and hypertension. This is an area for future research, whereby risk scores may be codified for patient selection to specific procedure settings.

Several prior studies have evaluated outcomes following TJA by procedure location. Using the National Surgical Quality Improvement Program database from the American College of Surgeons, Bovonratwet et al8 analyzed patients undergoing primary inpatient and outpatient elective TKA. They found no significant difference by setting in the incidence of minor or severe adverse events, or read-missions during the 30-day postoperative period.

A study by Nelson et al15 of matched patients who underwent outpatient and inpatient (LOS, 1 to 5 days) total hip arthroplasty—a relatively higher acuity procedure—also found procedure setting had little to no effect on outcomes or adverse events. The only exception was transfusion, which was significantly lower among those treated in the outpatient setting. In another study, Courtney et al14 compared patients undergoing elective outpatient and inpatient TJA (LOS greater than 24 hours); they found the outpatient TJA cohort had a significantly lower risk of complications than the inpatient cohort (8% vs 16%, respectively; P<.001), with no difference in reoperation (0.2% vs 0.2%, respectively; P=.796) or readmission (9.3% vs 0.5%, respectively; P=.322) in unadjusted analyses. After controlling for confounding variables, outpatient TJA remained significantly correlated with lower odds of complications (odds ratio, 0.46; 95% confidence interval, 0.37–0.57; P<.001).

Comparatively, the current study included both unmatched and matched analyses to better characterize the real-world profiles of patients selected for outpatient TKA, and outcomes then were further examined by setting during 90 days of follow-up. Similar to prior research, the choice of procedure setting appeared to have no adverse effect on outcomes. In fact, the current study found a significant improvement in the risk of minor complications among patients in the outpatient setting vs the rapid recovery inpatient setting.

Pain management in TJA is critical to patient satisfaction and recovery. Congruently, orthopedic surgeons represent the third-most common prescribers of opiates in US health care today, even when perioperative opiate use has been associated with increased risk of readmission, emergency department visits, infection, and revision TKA.19,20 In the current matched analysis, opiate use in the postoperative period was significantly lower among out-patients (80.4%) relative to rapid recovery inpatients (90.7%; P<.001). Although chart-level detail on specific pain management protocols is unavailable in health care claims, the current findings suggest surgeons operating in the outpatient setting have developed methods that reduce the use of opiate pain medication.

Finally, little has been published regarding the potential savings to the US health care system by shifting TKA location from an inpatient setting (including rapid recovery programs) to an outpatient setting. In a prior analysis of the Medicare 5% sample, Lovald et al21 found the 2-year total incremental Medicare payments after TKA were $6560 lower for the outpatient cohort relative to an inpatient stay of 1 to 2 days. Importantly, the study by Lovald et al21 was completed prior to Medicare reimbursement for outpatient TKA, which was implemented in January 2018.22 Comparatively, the current study examined a commercially insured population where outpatient TKA was reimbursed during the study period. The median 90-day episode cost savings per patient (from the perspective of the health plan payor) associated with the shift to outpatient was $6824, amounting to a per-patient savings of 22% relative to rapid recovery inpatient TKA.

Limitations

Given the nature of retrospective claims data, details specific to clinical management such as strategies and guidelines for anesthesia, blood product use, and surgical technique (eg, tourniquet-less or direct anterior approach) were unavailable. In addition, factors not coded in insurance claims, such as surgical skill or outcome-influencing factors (eg, tourniquet time) were not evaluated. Potentially confounding factors that involved care setting choice also could not be controlled for in matched analyses (eg, surgeon and patient preference, staffing volume, support services, and geographic convenience). Finally, the current study was performed in a commercial population; further enquiry is required to evaluate whether these findings extend to the Medicare population.

Conclusion

When outcomes were compared by exact matching of patient profiles, those who underwent outpatient TKA demonstrated a significantly lower risk of minor complications, with equivalent risk of major complications and 90-day all-cause readmission. The results of this study suggest that among carefully selected patients, outpatient TKA is a safe and effective option with the opportunity for significant payor cost savings.

References

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  21. Lovald ST, Ong KL, Malkani AL, et al. Complications, mortality, and costs for out-patient and short-stay total knee arthroplasty patients in comparison to standard-stay patients. J Arthroplasty. 2014;29(3):510–515. https://doi.org/10.1016/j.arth.2013.07.020 PMID: doi:10.1016/j.arth.2013.07.020 [CrossRef]
  22. Centers for Medicare & Medicaid Services. January2018update of the Hospital Outpatient Prospective Payment System (OPPS). Retrieved from https://www.cms.gov/Out-reach-and-Education/Medicare-Learning-Network-MLN/MLNMattersArticles/downloads/MM10417.pdf. Accessed May 18, 2018.

Patient demographics and clinical characteristics

UnmatchedMatched


OutpatientRapid Recovery InpatientP-ValueaOutpatientRapid Recovery InpatientP-Valueb


N9698,101< 0.0001863863
Age< 0.00010.741
  Mean57.260.957.3957.51
  SD6.58.86.326.37
  Median58615858
Age Group< 0.00011.000
  18–444.1%3.0%3.5%3.5%
  45–5424.5%17.9%23.3%23.3%
  55–6466.6%51.4%68.7%68.7%
  65+4.9%27.7%4.5%4.5%
Female56.4%51.0%0.00256.8%56.8%1.000
Census Region< 0.00011.000
  Midwest41.7%32.6%41.7%41.7%
  Northeast4.6%11.3%3.7%3.7%
  South31.9%37.3%33.0%33.0%
  West21.9%18.8%21.6%21.6%
Primary Payor< 0.00011.000
  Commercial95.4%72.2%95.5%95.5%
  Medicare Advantage4.6%27.9%4.5%4.5%
Index Year0.1391.000
  201451.1%53.7%50.8%50.8%
  201548.9%46.4%49.3%49.3%
Charlson Score (CCI)< 0.00010.999
  Mean0.230.400.150.15
  SD0.600.830.500.52
  Median0.000.000.000.00
CCI Grouping< 0.00011.000
  084.2%74.0%89.1%89.1%
  110.5%16.2%7.9%7.9%
  2+5.3%9.8%3.0%3.0%
Baseline Through Index Clinical Diagnoses
  Hypertension44.6%60.6%< 0.000144.4%44.4%1.000
  Obesec19.7%25.6%< 0.000118.0%18.0%1.000
  Diabetes11.5%16.5%< 0.00018.8%8.8%1.000
  Chronic Obstructive Pulmonary Disease7.4%12.9%< 0.00015.9%5.9%1.000
  History of Smoking5.2%17.0%< 0.00013.9%3.9%1.000
  Obstructive Sleep Apnea7.6%13.3%< 0.00015.3%5.3%1.000
  Coronary Artery Disease2.8%8.9%< 0.00012.3%2.3%1.000
  Nutritional Anemia1.9%2.6%0.1831.9%2.7%0.262
  Overweightc1.6%3.0%0.0120.6%0.6%1.000
  Congestive Heart Failure0.5%2.5%0.0000.1%0.1%1.000
  Liver Disease or Cirrhosis1.4%1.6%0.7880.6%0.8%0.527
  Bleeding Disorderd0.6%1.2%0.1650.5%0.9%0.248

Co-Occurring comorbidities among unmatched outpatients

IncidenceComorbiditiesHypertensionObesityDiabetes without ComplicationsChronic Pulmonary DiseaseObstructive Sleep ApneaHistory of Smoking
44.6%Hypertensionn/a12.2%7.5%4.5%4.2%3.5%
19.7%Obesity12.2%n/a3.2%1.9%2.7%1.4%
11.0%Diabetes without Complications7.5%3.2%n/a1.0%2.0%0.7%
7.4%Chronic Pulmonary Disease4.5%1.9%1.0%n/a1.2%0.9%
7.6%Obstructive Sleep Apnea4.2%2.7%2.0%1.2%n/a0.8%
5.2%History of Smoking3.5%1.4%0.7%0.9%0.8%n/a

Incidence

12.2%Hypertension & Obesityn/an/a2.6%1.3%1.8%1.1%
7.5%Hypertension & Diabetes w out CCn/a2.6%n/a0.8%1.3%0.4%
4.5%Hypertension & Chronic pulmonary diseasen/a1.3%0.8%n/a0.7%0.8%
4.2%Hypertension & Sleep Apnean/a1.8%1.3%0.7%n/a0.7%
3.5%Hypertension & Smokingn/a1.1%0.4%0.8%0.7%n/a

Hospitalization characteristics and incidence of complications from day of admission through 90-day post-discharge follow-up period

UnmatchedMatched


OutpatientRapid Recovery InpatientP-ValueaOutpatientRapid Recovery InpatientP-Valueb


N9698,101863863
First Discharge Destination< 0.0001< 0.0001
  Home Under Self-Care94.5%99.4%94.6%99.3%
  Home with Health Aid5.5%0.6%5.5%0.7%
≥1 Physical Therapy Visit During Follow-upc85.6%84.6%0.46286.2%85.3%0.586
Opiate Use
  Opiate Pain Medication Use80.0%82.4%0.07680.4%90.7%< 0.0001
Minor Complicationsd3.0%6.2%< 0.00012.8%5.8%0.002
Major Complicationse5.4%9.9%< 0.00015.2%6.7%0.173
Specific Complications
  Nausea and Vomiting2.9%3.4%0.4643.0%3.6%0.500
  Urinary Tract Infection1.9%3.7%0.0041.9%2.8%0.182
  Any Infectionf2.0%1.6%0.4152.0%1.4%0.353
  Transfusion (autologous or allogeneic)0.2%1.7%< 0.00010.2%1.7%0.002
  Deep Vein Thrombosis0.9%1.5%0.1751.0%1.4%0.513
  Urinary or renal complications0.5%0.8%0.5500.6%0.4%0.480
  Myocardial Infarction0.1%1.7%< 0.00010.1%0.9%0.020
  Pneumonia0.6%0.6%0.8210.6%0.9%0.405
  Hemorrhage, hematoma, seroma0.8%1.1%0.6170.6%1.3%0.134
  Cardiac complications0.1%0.4%0.3600.1%0.6%0.103
  Pulmonary Embolism0.6%0.6%1.0000.0%0.0%na
  Wound disruption0.1%0.0%0.2880.1%0.0%0.317

Total health plan payments (USD)

UnmatchedMatched


OutpatientRapid recovery InpatientP-ValueaOutpatientRapid recovery InpatientP-Valueb


Total Index Visit Paymentc
  Mean (SD)$23,929 ($15,332)$26,811 ($12,363)< 0.0001$24,058 ($15,186)$28,4856 ($11,170)< 0.0001
  P25$14,873$17,327$15,112$22,210
  Median$21,673$25,724$21,698$28,578
  P75$28,287$33,572$28,287$34,501
Among those readmitted, Total Readmission Payment
  Mean (SD)$25,836 ($19,409)$24,259 ($14,478)0.779$24,246 ($17,854)$25,629 ($13,217)0.273
  P25$10,433$13,678$10,377$14,770
  Median$19,648$22,929$17,475$26,761
  P75$33,453$32,144$32,972$32,904
Total 90-Day Coste
  Mean (SD)$28,548 ($18,068)$30,780 ($14,939)< 0.0001$28,440 ($17,566)$32,635 ($14,143)< 0.0001
  P25$18,117$20,000$18,298$24,739
  Median$24,825$29,063$24,749$31,573
  P75$32,102$37,752$32,060$38,740
Post-Acute Care as % of total 90-day cost15%12%0.00715%12%0.007

Authors

The authors are from the Medical Affairs Department, Medtronic, Portsmouth, New Hampshire.

The authors were full-time employees of Medtronic while engaged in this research. Ms Kimball and Ms Nichols are still full-time employees of Medtronic. All of the authors hold stock in Medtronic.

The authors thank Jeanne McAdara, PhD, for professional assistance with manuscript preparation.

Correspondence should be addressed to: Joshua G. Vose, MD, MBA ( josh.vose@gmail.com).

Received: July 02, 2018
Accepted: January 02, 2019
Posted Online: November 26, 2019

10.3928/01477447-20191122-01

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