The Rise of Medicare Advantage: Effects on Total Joint Arthroplasty Patient Care and Research

Medicare Advantage is Associated with Higher Mortality After Antibiotic Spacer Placement for Periprosthetic Joint Infection

INTRODUCTION

Privatized Medicare Advantage (MA) plans are an alternative to traditional Medicare (TM). We sought to identify differences in 90-day postoperative mortality and non-fatal adverse events between TM and MA patients undergoing stage one antibiotic spacer placement for periprosthetic joint infection (PJI) of the hip or knee.

METHODS

A nationally representative database was queried from 2015 to 2021 for adult patients undergoing stage one antibiotic spacer placement for PJI. Using the International Classification of Disease, Tenth Revision (ICD-10), and Current Procedural Terminology (CPT) codes, as well as hospital charges for antibiotics, patients undergoing stage one exchange arthroplasty for PJI were identified. Patients were then grouped into TM and MA cohorts. The primary outcome was the odds of 90-day mortality. Multivariable logistic regressions were conducted to address possible confounding demographic, comorbidity, and hospital characteristics.

RESULTS

Of the 40,346 patients undergoing stage one spacer placement for PJI, 16,637 (41.2%) had TM coverage and 9,218 (22.8%) had MA coverage. Mortality within 90 days of surgery was higher in the MA cohort (1.4% versus 1.0%, P = 0.004). Multivariable logistic regression demonstrated significantly higher adjusted odds of mortality (aOR [adjusted odds ratio] = 1.42, 95% CI [confidence interval] = 1.11 to 1.81, P = 0.005) in MA patients compared to TM.

CONCLUSION

Even after accounting for available confounders with our multivariable analyses, patients enrolled in an MA plan were over 40% more likely to die within 90 days of surgery compared to patients who have TM coverage. Further study is necessary to better understand the underlying cause of this finding.

Is the Rise of Medicare Advantage Impacting the Fidelity of Traditional Medicare Claims Data? Implications for Reporting of Long-Term Total Hip Arthroplasty Survivorship

BACKGROUND

Arthroplasty registries often use traditional Medicare (TM) claims data to report long-term total hip arthroplasty (THA) survivorship. The purpose of this study was to determine whether the large number of patients leaving TM for Medicare Advantage (MA) has compromised the fidelity of TM data.

METHODS

We identified 10,962 THAs in 9,333 Medicare-eligible patients who underwent primary THA from 2000 to 2020 at a single institution. Insurance type was analyzed, and 83% of patients had TM at the time of THA. Survivorship free from any revision or reoperation was calculated for patients who have TM. The same survivorship end points were recalculated with censoring performed when a patient transitioned to an MA plan after their primary THA to model the impact of losing patients from the TM dataset. Differences in survivorship were compared. The mean follow-up was 7 years.

RESULTS

From 2000 to 2020, there was a decrease in TM insurance (93 to 73%) and a corresponding increase in MA insurance (0 to 19%) among THA patients. Following THA, 23% of TM patients switched to MA. For patients who had TM at the time of surgery, 15-year survivorship free from any reoperation or revision was 90% and 93%, respectively. When censoring patients upon transition from TM to MA, survivorship free from any reoperation became significantly higher (92 versus 90% at 15 years; hazard ratio = 1.16, P = .033), and there was a trend toward higher survivorship free from any revision (95 versus 93% at 15 years; hazard ratio = 1.16, P = .074).

CONCLUSIONS

Approximately 1 in 4 patients left TM for MA after primary THA, effectively making them lost to follow-up within TM datasets. The mass exodus of patients out of TM appears to have led to a slight overestimation of survivorship free from any reoperation and trended toward overestimating survivorship free from any revision. If MA continues to grow, efforts to obtain MA data will become even more important.

Dilution of humoral immunity: Results from a natural history study of healthy total knee arthroplasty patients

The incidence of prosthetic joint infection (PJI) following elective primary total knee arthroplasty (TKA) is very low but serious risk remains. To identify unknown risk factors, we completed a natural history study of IgG specific for Staphylococcus aureus antigens previously phenotyped as protective (anti-Atl) and pathogenic (anti-Isd). Twenty-five male and 25 female optimized patients 50-85 years of age and BMI 24-39 undergoing primary TKA were prospectively enrolled. Blood sampling was performed preoperatively, postoperative Day 1, and at 2, 6, and 12 weeks, to assess serum cytokine, anti-staphylococcal IgG levels and anti-tetanus toxoid IgG measured via custom Luminex assay. Clinical, demographic, and PROMIS-10 data were collected with outcomes to 2 years postop. All participants completed the study and 2-year follow-up. No patients were readmitted or noted to develop a surgical site infection or serious adverse event, and patient-reported outcomes were improved. Serology revealed a highly significant decrease in six out of eight antibody titers against specific S. aureus antigens on Day 1 (p < 0.0001), five of which normalized to preoperative levels within 2 weeks. These changes were commensurate with a decrease and recovery of anti-tetanus toxoid titers, and a 20% drop in hemoglobin 13.8 ± 1.7 at preop to 11.1 ± 1.8 mg/dL on Day 1 (p < 0.0001). After TKA, a significant decrease in humoral immunity commensurate with blood loss and hemodilution was recorded. This decrease in circulating anti-staphylococcal antibodies in the early postop period may represent a periprosthetic joint infection risk factor for patients.

Rising Costs and Diminishing Surgeon Reimbursement From Primary to Revision Total Hip and Knee Arthroplasty: An Analysis of Medicare Advantage and Commercial Insurance

BACKGROUND

Revision total joint arthroplasty (rTJA) is a resource-intensive procedure addressing failed primary total joint hip (total hip arthroplasty [THA]) and knee arthroplasty (total knee arthroplasty [TKA]). Despite predictions of increased demand, reimbursement for rTJA has not kept pace with increasing costs and may be insufficient compared with primary procedures. The study aimed to highlight the diminishing surgeon reimbursement between primary and revision THA (rTHA) and TKA.

METHODS

This study is a retrospective analysis of billing data for primary and rTHA and TKA procedures from a single institution between 2019 and 2022. Insurance claims and charges data were provided by a local affiliate of a major national carrier which includes Medicare Advantage (MA) and commercial patients. Using insurance data, the study evaluates the total surgery costs for primary and rTHA and TKA and the individual charges that make up the total surgery cost.

RESULTS

Nine hundred five patients insured by the same carrier, who underwent a primary or rTJA, were identified. Irrespective of MA or commercial insurance, the average surgery cost for a primary THA was $26,043, compared with $53,456 for rTHA. Surgeon reimbursement for primary THA was 20% ($5,323) of the total surgery cost. Despite the doubled surgery cost for rTHA, surgeon reimbursement was 10% ($5,257) of the total surgery cost. Primary TKA surgery costs were $24,489, while revision costs were $43,074. Surgeon reimbursement for primary TKA was 20% ($4,918) of the total surgery cost, while reimbursement for revision TKA was 13% ($5,560). MA reimbursement was markedly lower than commercial reimbursement for primary and revision cases.

CONCLUSION

Despite the higher total costs for rTJA, surgeon reimbursement is disproportionately diminished. The findings highlight the lack of incentive for revision cases. Surgeon reimbursement from MA and commercially insured patients for rTJA remains inadequate. This may limit patient access-to-care, leading to suboptimal outcomes and increased healthcare utilization.

Risk Factors Associated with Thromboembolic Complications After total Hip Arthroplasty: An Analysis of 1,129 Pulmonary Emboli

INTRODUCTION

Venous thromboembolism (VTE) remains a dangerous complication after total hip arthroplasty (THA), despite advances in chemoprophylactic measures. This study aimed to identify risk factors of developing pulmonary embolism (PE) and deep vein thrombosis (DVT) after THA using a modern cohort of patients reflecting contemporary practices.

METHODS

The Premier Healthcare Database was queried for primary, elective THAs from January 1st, 2015, to December 31st, 2021. Patients who developed PE or DVT within 90 days of THA were compared with patients who did not develop any postoperative VTE. Differences in patient demographics, comorbidities, hospital factors, perioperative medications, chemoprophylactic agents, and allogeneic blood transfusion were compared between cohorts. Multivariable logistic regression models were used to identify independent risk factors of PE and DVT. In total, 544,298 THAs were identified, of which 1,129 (0.21%) developed a PE and 1,799 (0.33%) developed a DVT.

RESULTS

Patients diagnosed with a PE had significantly higher rates of in-hospital death (2.6% vs 0.1%, P < 0.001) compared with those without a PE. Age (adjusted odds ratio: 1.02 per year, 95% confidence interval [CI]: 1.01 to 1.03) and Black race (aOR: 1.52, 95% CI: 1.24 to 1.87) were associated with an increased risk of PE. Comorbidities associated with increased risk of PE included chronic pulmonary disease (aOR: 1.58, 95% CI: 1.36 to 1.84), pulmonary hypertension (aOR: 2.06, 95% CI: 1.39 to 3.04), and history of VTE (aOR: 2.38, 95% CI: 1.98 to 2.86). Allogeneic blood transfusion (aOR: 2.40, 95% CI: 1.88 to 3.06) was also associated with an increased risk of PE while dexamethasone utilization was associated with a reduced risk (aOR: 0.83, 95% CI: 0.73 to 0.95).

DISCUSSION

Increasing age; Black race; allogeneic blood transfusion; and comorbidities, including chronic pulmonary disease, pulmonary hypertension, and history of VTE, were independent risk factors of PE after THA. Given the increased mortality associated with PE, patients should be carefully evaluated for these factors and managed with an appropriate chemoprophylactic regimen.

Medicare Advantage in Soft Tissue Sarcoma May Be Associated with Worse Patient Outcomes

Medicare Advantage healthcare plans may present undue impediments that result in disparities in patient outcomes. This study aims to compare the outcomes of patients who underwent STS resection based on enrollment in either traditional Medicare (TM) or Medicare Advantage (MA) plans. The Premier Healthcare Database was utilized to identify all patients ≥65 years old who underwent surgery for resection of a lower-extremity STS from 2015 to 2021. These patients were then subdivided based on their Medicare enrollment status (i.e., TM or MA). Patient characteristics, hospital factors, and comorbidities were recorded for each cohort. Bivariable analysis was performed to assess the 90-day risk of postoperative complications. Multivariable analysis controlling for patient sex, as well as demographic and hospital factors found to be significantly different between the cohorts, was also performed. From 2015 to 2021, 1858 patients underwent resection of STS. Of these, 595 (32.0%) had MA coverage and 1048 (56.4%) had TM coverage. The only comorbidities with a significant difference between the cohorts were peripheral vascular disease (p = 0.027) and hypothyroidism (p = 0.022), both with greater frequency in MA patients. After controlling for confounders, MA trended towards having significantly higher odds of pulmonary embolism (adjusted odds ratio (aOR): 1.98, 95% confidence interval (95%-CI): 0.58-6.79), stroke (aOR: 1.14, 95%-CI: 0.20-6.31), surgical site infection (aOR: 1.59, 95%-CI: 0.75-3.37), and 90-day in-hospital death (aOR 1.38, 95%-CI: 0.60-3.19). Overall, statistically significant differences in postoperative outcomes were not achieved in this study. The authors of this study hypothesize that this may be due to study underpowering or the inability to control for other oncologic factors not available in the Premier database. Further research with higher power, such as through multi-institutional collaboration, is warranted to better assess if there truly are no differences in outcomes by Medicare subtype for this patient population.