The ability of comorbidity indices to predict mortality in an orthopedic setting: a systematic review

Trends in the Adoption of Outpatient Joint Arthroplasties and Patient Risk: A Retrospective Analysis of 2019 to 2021 Medicare Claims Data

INTRODUCTION

Total joint arthroplasties (TJAs) have recently been shifting toward outpatient arthroplasty. This study aims to explore recent trends in outpatient total joint arthroplasty (TJA) procedures and examine whether patients with a higher comorbidity burden are undergoing outpatient arthroplasty.

METHODS

Medicare fee-for-service claims were screened for patients who underwent total hip, knee, or shoulder arthroplasty procedures between January 2019 and December 2022. The procedure was considered to be outpatient if the patient was discharged on the same date of the procedure. The Hierarchical Condition Category Score (HCC) and the Charlson Comorbidity Index (CCI) scores were used to assess patient comorbidity burden. Patient adverse outcomes included all-cause hospital readmission, mortality, and postoperative complications. Logistic regression analyses were used to evaluate if higher HCC/CCI scores were associated with adverse patient outcomes.

RESULTS

A total of 69,520, 116,411, and 41,922 respective total knee, hip, and shoulder arthroplasties were identified, respectively. Despite earlier removal from the inpatient-only list, outpatient knee and hip surgical volume did not markedly increase until the pandemic started. By 2022Q4, 16%, 23%, and 36% of hip, knee, and shoulder arthroplasties were discharged on the same day of surgery, respectively. Both HCC and CCI risk scores in outpatients increased over time ( P < 0.001).

DISCUSSION

TJA procedures are shifting toward outpatient surgery over time, largely driven by the COVID-19 pandemic. TJA outpatients' HCC and CCI risk scores increased over this same period, and additional research to determine the effects of this should be pursued.

LEVEL OF EVIDENCE

Level III, therapeutic retrospective cohort study.

Lower Revenue Surplus in Medicare Advantage Versus Private Commercial Insurance for Total Joint Arthroplasty: An Analysis of a Single Payor Source at One Institution

BACKGROUND

Since the Affordable Care Act was passed in 2010, reductions in Medicare reimbursement have led to larger discrepancies between the relative cost of Medicare patients and privately insured patients. The purpose of this study was to compare reimbursement between Medicare Advantage and other insurance plans in patients undergoing total hip arthroplasty (THA) and total knee arthroplasty (TKA).

METHODS

Patients of a single commercial payor source who underwent primary unilateral TKA or THA at 1 institution between the dates of January 4 and June 30, 2021, were included (n = 833). Variables included insurance type, medical comorbidities, total costs, and surplus amounts. The primary outcome measure was revenue surplus between Medicare Advantage and Private Commercial plans. t-tests, Analyses of Variance, and Chi-Squared tests were used for analysis. A THA represented 47% of cases and a TKA 53%. Of these patients, 31.5% had Medicare Advantage and 68.5% had Private Commercial insurance. Medicare Advantage patients were older and had higher medical comorbidity risk for both TKA and THA.

RESULTS

Significant differences were observed in medical costs between Medicare Advantage and Private Commercial insurance for THA ($17,148 versus $31,260, P < .001) and TKA ($16,723 versus $33,593, P < .001). Additionally, differences were seen in surplus amounts between Medicare Advantage and Private Commercial insurance for THA ($3,504 versus $7,128, P < .001) and TKA ($5,581 versus $10,477, P < .001). Deficits were higher in Private Commercial patients undergoing TKA (15.2 versus 6%, P = .001).

CONCLUSION

The lower average surplus associated with Medicare Advantage plans may lead to financial strain on provider groups who care for these patients and face additional overhead costs.

Comparison of diagnosis-based risk adjustment methods for episode-based costs to apply in efficiency measurement

BACKGROUND

The recent rising health spending intrigued efficiency and cost-based performance measures. However, mortality risk adjustment methods are still under consideration in cost estimation, though methods specific to cost estimate have been developed. Therefore, we aimed to compare the performance of diagnosis-based risk adjustment methods based on the episode-based cost to utilize in efficiency measurement.

METHODS

We used the Health Insurance Review and Assessment Service-National Patient Sample as the data source. A separate linear regression model was constructed within each Major Diagnostic Category (MDC). Individual models included explanatory (demographics, insurance type, institutional type, Adjacent Diagnosis Related Group [ADRG], diagnosis-based risk adjustment methods) and response variables (episode-based costs). The following risk adjustment methods were used: Refined Diagnosis Related Group (RDRG), Charlson Comorbidity Index (CCI), National Health Insurance Service Hierarchical Condition Categories (NHIS-HCC), and Department of Health and Human Service-HCC (HHS-HCC). The model accuracy was compared using R-squared (R2), mean absolute error, and predictive ratio. For external validity, we used the 2017 dataset.

RESULTS

The model including RDRG improved the mean adjusted R2 from 40.8% to 45.8% compared to the adjacent DRG. RDRG was inferior to both HCCs (RDRG adjusted R2 45.8%, NHIS-HCC adjusted R2 46.3%, HHS-HCC adjusted R2 45.9%) but superior to CCI (adjusted R2 42.7%). Model performance varied depending on the MDC groups. While both HCCs had the highest explanatory power in 12 MDCs, including MDC P (Newborns), RDRG showed the highest adjusted R2 in 6 MDCs, such as MDC O (pregnancy, childbirth, and puerperium). The overall mean absolute errors were the lowest in the model with RDRG ($1,099). The predictive ratios showed similar patterns among the models regardless of the  subgroups according to age, sex, insurance type, institutional type, and the upper and lower 10th percentiles of actual costs. External validity also showed a similar pattern in the model performance.

CONCLUSIONS

Our research showed that either NHIS-HCC or HHS-HCC can be useful in adjusting comorbidities for episode-based costs in the process of efficiency measurement.

Graft failure within 2 years of isolated anterior cruciate ligament reconstruction is associated with increased risk of secondary meniscus tears

PURPOSE

A debilitating complication following anterior cruciate ligament reconstruction is a secondary meniscus tear. Currently, the literature is mixed regarding the risk factors associated with the incidence of secondary meniscus tears. The aim of this study was to investigate risk factors associated with meniscus tears following an isolated primary anterior cruciate ligament reconstruction. ACL graft failure was hypothesized to be the strongest risk factor for secondary meniscal injury occurrence.

METHODS

A retrospective cohort analysis was performed using the PearlDiver Database. Patients with a primary anterior cruciate ligament reconstruction were identified in the database. Patients with concomitant knee ligament injury or meniscus injury present at the time the index procedure were excluded. Patients were grouped to those who had a secondary meniscus tear within 2 years following anterior cruciate ligament reconstruction and those who did not. Univariate analysis and multivariable regression analysis was conducted to identify significant risk factors for a secondary meniscus tear.

RESULTS

There were 25,622 patients meeting criteria for inclusion in this study. Within 2 years from the primary anterior cruciate ligament reconstruction, there were 1,781 patients (7.0%) that experienced a meniscus tear. Graft failure had the highest odds of having a postoperative meniscus tear within 2 years (OR: 4.1; CI 3.5-4.8; p < 0.002). Additional significant risk factors included tobacco use (OR: 2.0; CI 1.0-3.1; p < 0.001), increased Charlson Comorbidity Index (OR: 1.2; CI 1.1-1.4), male gender (OR: 1.1; CI 1.1-1.2; p < 0.001), obesity (OR: 1.1; CI 1.1-1.2; p < 0.001), delayed surgery (OR:1.1; CI 1.1-1.2; p < 0.002), and patients age 30 and older (OR: 1.0; CI 1.0-1.0; p < 0.001).

CONCLUSIONS

This study found that anterior cruciate ligament graft failure is the strongest predictor of post-operative meniscus tears. Other risk factors, including tobacco use, increased CCI, male gender, obesity, delayed surgery, and age 30 and older, were established, with several being modifiable. Therefore, targeted preoperative optimization of modifiable risk factors and postoperative protocols may reduce the risk of secondary meniscus tears.

LEVEL OF EVIDENCE

Level III, prognostic trial.

Comparing Risk Assessment Between Payers and Providers: Inconsistent Agreement in Medical Comorbidity Records for Patients Undergoing Total Joint Arthroplasty

BACKGROUND

The proper risk adjustment for total hip arthroplasty (THA) and total knee arthroplasty (TKA) relies on an accurate assessment of comorbidity profiles by both the payer and the institution. The purpose of this study was to determine how strongly comorbidities tracked by our institution agreed with the same comorbidities reported by payers in patients undergoing THA and TKA.

METHODS

All patients of a single payer undergoing primary THA and TKA at a single institution between January 5, 2021 and March 31, 2022 were included (n = 876). There were 8 commonly collected medical comorbidities obtained from institutional medical records and matched with patient records reported by the payer. Fleiss Kappa tests were used to determine agreement of payer data with institutional records. There were 4 medical risk calculations collected from our institutional records and compared with an insurance member risk score reported by the payer.

RESULTS

Comorbidities reported by the institution differed significantly from those reported by payers, with Kappa varying between 0.139 and 0.791 for THA, and 0.062 and 0.768 for TKA. Diabetes was the only condition to demonstrate strong agreement for both procedures (THA; k = 0.791, TKA; k = 0.768). The insurance member risk score demonstrates the closest association with total cost and surplus for THA regardless of insurance type and for TKA procedures paid for with private commercial insurance.

CONCLUSION

There is a lack of agreement between medical comorbidities within payer and institutional records for both THA and TKA. These differences may put institutions at a disadvantage within value-based care models and when optimizing patients perioperatively.

The Impact of Hospital Exposures Prior to Total Knee Arthroplasty on Postoperative Outcomes

Background

Total knee arthroplasty (TKA) procedures are expected to grow exponentially in the upcoming years, highlighting the importance of identifying preoperative risk factors that predispose patients to poor outcomes. The present study sought to determine if preoperative healthcare events (PHEs) influenced outcomes following TKA.

Methods

This was a retrospective review of all patients who underwent TKA at a single institution from June 2011 to April 2022. Patients who had a PHE within 90 days of surgery, defined as an emergency department visit or hospital admission, were compared to patients with no history of PHE. Patients who underwent revision, nonelective, and/or bilateral TKA were excluded. Chi-squared analysis and independent sample t-tests were used to determine significant differences between demographic variables. All significant covariates were included in binary logistic regressions used to predict discharge disposition, 90-day readmission, and 1-year revision.

Results

Of the 10,869 patients who underwent TKA, 265 had ≥1 PHE. Patients who had a PHE were significantly more likely to require facility discharge (odds ratio [OR]: 1.662; P = .001) than patients who did not have a PHE. Any PHE predisposed patients to significantly higher 90-day readmission rates (OR: 2.173; P = .002). Patients with ≥2 PHEs were at a significantly higher risk of 1-year revision (OR: 5.870; P = .004) compared to patients without a PHE.

Conclusions

Our results demonstrate that PHEs put patients at significantly greater risk of facility discharge, 90-day readmission, and 1-year revision. Moving forward, consideration of elective surgery scheduling in the context of a recent PHE may lead to improved postoperative outcomes.

Level III Evidence

Retrospective Cohort Study.

Patterns in hospital admissions for adults with congenital heart disease for non-cardiac procedures

OBJECTIVE

Advances in management of congenital heart disease (CHD) have led to an increasing population of adults with CHD, many of whom require non-cardiac procedures. The objectives of this study were to describe the characteristics of these patients, their distribution among different hospital categories and the characteristics determining this distribution, and mortality rates following noncardiac procedures.

METHODS

We retrospectively analysed 27 state inpatient databases. Encounters with CHD and non-cardiac procedures were included. The location of care was classified into two categories: hospitals with and without cardiac surgical programmes. Variables included were demographics, comorbidity index, mortality. Multivariable logistic regression was used to explore predictors for care in different locations.

RESULTS

The cohort consisted of 12 944 encounters in 1206 hospitals. Most patients were cared for in hospitals with a cardiac surgical programme (78.1%). Patients presenting to hospitals with a cardiac surgical programme presented with higher comorbidity index (6 (IQR: 0-19) vs 2 (IQR: -3-14), p<0.001) than patients presenting to hospitals without a cardiac surgical programme. Mortality was higher in hospitals with cardiac surgical programmes compared with hospitals without cardiac surgical programmes (4.0% vs 2.3%, p<0.001). Factors associated with provision of care at a hospital with a cardiac surgical programme were comorbidity index (>7: OR 2.01 (95% CI 1.83 to 2.21), p<0.001; 2-7: OR 1.59 (95% CI 1.41 to 1.79), p<0.001) and age (18-44 years: OR 1.43 (95% CI 1.26 to 1.62), p<0.001; 45-64 years: OR 1.21 (95% CI 1.08 to 1.34), p<0.001).

CONCLUSION

Adults with CHD undergoing non-cardiac procedures are mainly cared for in hospitals with a cardiac surgical programme and have greater comorbidities and higher mortality than those in centres without cardiac surgical programmes. Risk stratification and locoregional accessibility need further assessment to fully understand admission patterns.

Renal disease and diabetes increase the risk of failed outpatient management of cellulitic hand infections: a retrospective cohort study

BACKGROUND

Hand infections are heterogeneous, and some may undergo successful outpatient management. There are no strict guidelines for determining which patients will likely require inpatient admission for successful treatment, and many patients succeed with outpatient therapy. We sought to determine risk factors for failed outpatient management of cellulitic hand infections.

METHODS

We performed a retrospective review of patients who presented to the Emergency Department (ED) for hand cellulitic infections over five years, from 2014 to 2019. Vital signs, lab markers, Charlson Comorbidity Index (CCI), Elixhauser Comorbidity Measure (ECM), and antibiotic use were investigated. Discharge from the ED without subsequent admission was considered an outpatient success, while admission within 30 days of the prior visit was considered a failure. Continuous variables were compared with Welch's t test, and categorical data with Fisher's exact tests. Multivariable logistic regression was performed on comorbidities. Multiple testing adjustment was performed on p-values to generate q-values.

RESULTS

Outpatient management was attempted for 1,193 patients. 31 (2.6%) infections failed treatment, and 1,162 (97.4%) infections succeeded. Attempted outpatient treatment was 97.4% successful. Multivariable analysis demonstrated higher odds of failure with renal failure according to both CCI (OR 10.2, p < 0.001, q = 0.002) and ECM (OR 12.63, p = 0.003, q = 0.01) and with diabetes with complications according to the CCI (OR 18.29, p = 0.021, q = 0.032).

CONCLUSIONS

Outpatient treatment failure was higher in patients with renal failure and complicated diabetes. These patients require a high index of suspicion for outpatient failure. These comorbidities should influence consideration for inpatient therapy though most patients can undergo successful treatment as outpatients.

LEVEL OF EVIDENCE

Level III.

How to Create an Orthopaedic Arthroplasty Database Project: A Step-by-Step Guide Part II: Study Execution

In recent years, the use of national databases in orthopaedic surgery research has grown substantially with database studies comprising an estimated ∼10% of all published lower extremity arthroplasty research. The aim of this review is to serve as a guide on how to: (1) design; (2) execute; and (3) publish an orthopaedic database arthroplasty project. In part II, we discuss how to collect data, propose a novel checklist/standards for presenting orthopaedic database information (SOPOD), discuss methods for appropriate data interpretation/analysis, and summarize how to convert findings to a manuscript (providing a previously published example study). Data collection can be divided into two stages: baseline patient demographics and primary/secondary outcomes of interest. Our proposed SOPOD is more orthopaedic-centered and builds upon previous standards for observational studies from the EQUATOR network. There are a host of statistical methods available to analyze data to compare baseline demographics, primary/secondary outcomes, and reduce type 1 errors seen in large datasets. When drafting a manuscript, it is important to consider and discuss the limitations of database studies, including their retrospective nature, issues with coding/billing, differences in statistical versus clinical significance (or relevance), lack of surgery details (approach, laterality, and implants), and limited sampling or follow-up. We hope this paper will serve as a starting point for those interested in conducting lower extremity arthroplasty database studies.

Utilization Trends of Total Ankle Arthroplasty and Ankle Fusion for Tibiotalar Osteoarthritis: A Nationwide Analysis of the United States Population

Introduction: Studies evaluating utilization and trends of total ankle arthroplasty (TAA) and ankle fusion (AF) are sparse. The purpose of this study was to use a nationwide administrative claims database to compare baseline demographics between TAA and ankle arthrodesis and to determine whether patients who had a TAA have increased rates of: (1) utilization, (2) in-hospital length of stay (LOS), and (3) costs of care. Methods: PearlDiver, a nationwide claims database was queried from 2005 to December 2013 for all patients who underwent primary TAA or AF for the treatment of osteoarthritis of the ankle and foot. Baseline demographics of age, sex, geographic distribution, and the prevalence of comorbidities comprising the Elixhauser comorbidity index (ECI) were compared between patients who had TAA and AF. Linear regression was used to compare differences in utilization and in-hospital LOS between the 2 cohorts during the study interval. Annual charges and reimbursement rates for TAA were assessed during the study period. A P value less than .05 was considered to be statistically significant. Results: A total of 21 433 patients undergoing primary TAA (n = 7126) and AF (n = 14 307) were included. Patients undergoing TAA had significantly greater ECI driven by arrythmias, congestive heart failure, diabetes mellitus, electrolyte/fluid disorders, iron deficiency anemia than patients undergoing AF (P < .001). From 2005 to 2013, TAA utilization increased from 21.5% to 49.4% of procedures (P < .0001). There was reduced in-hospital LOS over the time interval for patients with TAA compared with AF (2.15 days vs. 3.11 days, P < .0001). Total ankle arthroplasty reimbursements remained stable while charges per patient increased significantly from $40 203.48 in 2005 to doubling by the end of 2013 to $86 208.59 (P < .0001). Conclusion: This study demonstrated increased use of TAA compared to AF showing decreased in-hospital LOS and increased cost of care with stagnant reimbursement rates.Level of Evidence: Level III.