Background 

Demographic factors have been implicated in THA and TKA outcome disparities. Specifically, patients’ racial backgrounds have been reported to influence outcomes after surgery, including length of stay, discharge disposition, and inpatient readmissions. However, in the United States, health-impacting socioeconomic disadvantage is sometimes associated with racial differences in ways that can result in important confounding, thereby raising the question of whether race-associated post-THA/TKA adverse outcomes are an independent function of race or a byproduct of confounding from socioeconomic deprivation, which is potentially addressable. To explore this, we used the Area Deprivation Index (ADI) as a proxy for socioeconomic disadvantage, since it is a socioeconomic parameter that estimates the likely deprivation associated with a patient’s home address.

Questions/purposes 

The goal of this study was to investigate (1) whether race (in this study, Black versus White) was independently associated with adverse outcomes, including prolonged length of stay (LOS > 3 days), nonhome discharge, 90-day readmission, and emergency department (ED) visits while controlling for age, gender, BMI, smoking, Charlson comorbidity index (CCI), and insurance; and (2) whether socioeconomic disadvantage, measured by ADI, substantially mediated any association between race and any of the aforementioned measured outcomes.

Methods 

Between November 2018 and December 2019, 2638 underwent elective primary THA and 4915 patients underwent elective primary TKA for osteoarthritis at one of seven hospitals within a single academic center. Overall, 12% (742 of 5948) of patients were Black and 88% (5206 of 5948) were White. We included patients with complete demographic data, ADI data, and who were of Black or White race; with these criteria, 11% (293 of 2638) were excluded in the THA group, and 27% (1312 of 4915) of patients were excluded in the TKA group. In this retrospective, comparative study, patient follow-up was obtained using a longitudinally maintained database, leaving 89% (2345 of 2638) and 73% (3603 of 4915) for analysis in the THA and TKA groups, respectively. For both THA and TKA, Black patients had higher ADI scores, slightly higher BMIs, and were more likely to be current smokers at baseline. Furthermore, within the TKA cohort there was a higher proportion of Black women compared with White women. Multivariable regression analysis was utilized to assess associations between race and LOS of 3 or more days, nonhome discharge disposition, 90-day inpatient readmission, and 90-day ED admission, while adjusting for age, gender, BMI, smoking, CCI, and insurance. This was followed by a mediation analysis that explored whether the association between race (the independent variable) and measured outcomes (the dependent variables) could be partially or completely attributable to confounding from the ADI (the mediator, in this model). The mediation effect was measured as a percentage of the total effect of race on the outcomes of interest that was mediated by ADI.

Results 

In the THA group, after adjusting for age, gender, BMI, smoking, CCI, and insurance, White patients had lower odds of experiencing an LOS of 3 days or more (OR 0.43 [95% confidence interval (CI) 0.31 to 0.59]; p < 0.001) and nonhome discharge (OR 0.39 [95% CI 0.27 to 0.56]; p < 0.001). In mediation analysis, ADI partially explained (or mediated) 37% of the association between race and LOS of 3 days or more (-0.043 [95% CI -0.063 to -0.026]; p < 0.001) and 40% of the association between race and nonhome discharge (0.041 [95% CI 0.024 to 0.059]; p < 0.001). However, a smaller direct association between race and both outcomes was observed (LOS 3 days or more: -0.075 [95% CI -0.13 to -0.024]; p = 0.004; nonhome discharge: 0.060 [95% CI 0.016 to 0.11]; p = 0.004). No association was observed between race and 90-day readmission or ED admission in the THA group. In the TKA group, after adjusting for age, gender, BMI, smoking, CCI, and insurance, White patients had lower odds of experiencing an LOS of 3 days or more (OR 0.41 [95% CI 0.32 to 0.54]; p < 0.001), nonhome discharge (OR 0.44 [95% CI 0.33 to 0.60]; p < 0.001), 90-day readmission (OR 0.54 [95% CI 0.39 to 0.77]; p < 0.001), and 90-day ED admission (OR 0.60 [95% CI 0.45 to 0.79]; p < 0.001). In mediation analysis, ADI mediated 19% of the association between race and LOS of 3 days or more (-0.021 [95% CI -0.035 to -0.007]; p = 0.004) and 38% of the association between race and nonhome discharge (0.029 [95% CI -0.016 to 0.040]; p < 0.001), but there was also a direct association between race and these outcomes (LOS 3 days or more: -0.088 [95% CI -0.13 to -0.049]; p < 0.001; nonhome discharge: 0.046 [95% CI 0.014 to 0.078]; p = 0.006). ADI did not mediate the associations observed between race and 90-day readmission and ED admission in the TKA group.

Conclusion 

Our findings suggest that socioeconomic disadvantage may be implicated in a substantial proportion of the previously assumed race-driven disparity in healthcare utilization parameters after primary total joint arthroplasty. Orthopaedic surgeons should attempt to identify potentially modifiable socioeconomic disadvantage indicators. This serves as a call to action for the orthopaedic community to consider specific interventions to support patients from vulnerable areas or whose incomes are lower, such as supporting applications for nonemergent medical transportation or referring patients to local care coordination agencies. Future studies should seek to identify which specific resources or approaches improve outcomes after TJA in patients with socioeconomic disadvantage.

Level of Evidence 

Level III, therapeutic study.

中文翻译：

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THA 和 TKA 后结果的种族差异在很大程度上是由黑人和白人患者的社会经济劣势所介导的

背景 

人口统计学因素与 THA 和 TKA 的结果差异有关。具体而言，据报道，患者的种族背景会影响手术后的结果，包括住院时间、出院处置和住院再入院率。然而，在美国，影响健康的社会经济劣势有时与种族差异相关，其方式可能导致重要的混杂，从而提出一个问题，即与种族相关的 THA/TKA 后不良后果是否独立于种族或社会经济剥夺混杂的副产品，这可能是可以解决的。为了探索这一点，我们使用区域剥夺指数 (ADI) 作为社会经济劣势的代表，

问题/目的 

本研究的目的是调查 (1) 种族（在本研究中，黑人与白人）是否与不良结果独立相关，包括住院时间延长（LOS > 3 天）、非家庭出院、90 天再入院和急诊科 (ED) 就诊，同时控制年龄、性别、BMI、吸烟、查尔森合并症指数 (CCI) 和保险；(2) 由 ADI 衡量的社会经济劣势是否在很大程度上介导了种族与上述任何衡量结果之间的任何关联。

方法 

2018 年 11 月至 2019 年 12 月期间，在一个学术中心的七家医院之一，有 2638 名患者接受了择期初次 THA，4915 名患者接受了择期初次 TKA 治疗骨关节炎。总体而言，12%（5948 人中的 742 人）患者为黑人，88%（5948 人中的 5206 人）为白人。我们纳入了具有完整人口统计数据、ADI 数据以及黑人或白人种族的患者；根据这些标准，THA 组排除了 11%（2638 名中的 293 名）患者，TKA 组中排除了 27%（4915 名中的 1312 名）患者。在这项回顾性比较研究中，使用纵向维护的数据库获得患者随访，THA 和 TKA 组分别有 89%（2638 人中的 2345 人）和 73%（4915 人中的 3603 人）用于分析。对于 THA 和 TKA，黑人患者的 ADI 评分较高，BMI 略高，并且在基线时更有可能是当前吸烟者。此外，在 TKA 队列中，与白人女性相比，黑人女性的比例更高。多变量回归分析用于评估种族与 3 天或更多天的 LOS、非家庭出院处置、90 天住院患者再入院和 90 天 ED 入院之间的关联，同时调整年龄、性别、BMI、吸烟、CCI 和保险. 随后进行调解分析，探讨种族（自变量）和测量结果（因变量）之间的关联是否可以部分或完全归因于 ADI（该模型中的调解人）的混杂。中介效应被测量为种族对 ADI 中介的感兴趣结果的总影响的百分比。此外，在 TKA 队列中，与白人女性相比，黑人女性的比例更高。多变量回归分析用于评估种族与 3 天或更多天的 LOS、非家庭出院处置、90 天住院患者再入院和 90 天 ED 入院之间的关联，同时调整年龄、性别、BMI、吸烟、CCI 和保险. 随后进行调解分析，探讨种族（自变量）和测量结果（因变量）之间的关联是否可以部分或完全归因于 ADI（该模型中的调解人）的混杂。中介效应被测量为种族对 ADI 中介的感兴趣结果的总影响的百分比。此外，在 TKA 队列中，与白人女性相比，黑人女性的比例更高。多变量回归分析用于评估种族与 3 天或更多天的 LOS、非家庭出院处置、90 天住院患者再入院和 90 天 ED 入院之间的关联，同时调整年龄、性别、BMI、吸烟、CCI 和保险. 随后进行调解分析，探讨种族（自变量）和测量结果（因变量）之间的关联是否可以部分或完全归因于 ADI（该模型中的调解人）的混杂。中介效应被测量为种族对 ADI 中介的感兴趣结果的总影响的百分比。在 TKA 队列中，与白人女性相比，黑人女性的比例更高。多变量回归分析用于评估种族与 3 天或更多天的 LOS、非家庭出院处置、90 天住院患者再入院和 90 天 ED 入院之间的关联，同时调整年龄、性别、BMI、吸烟、CCI 和保险. 随后进行调解分析，探讨种族（自变量）和测量结果（因变量）之间的关联是否可以部分或完全归因于 ADI（该模型中的调解人）的混杂。中介效应被测量为种族对 ADI 中介的感兴趣结果的总影响的百分比。在 TKA 队列中，与白人女性相比，黑人女性的比例更高。多变量回归分析用于评估种族与 3 天或更多天的 LOS、非家庭出院处置、90 天住院患者再入院和 90 天 ED 入院之间的关联，同时调整年龄、性别、BMI、吸烟、CCI 和保险. 随后进行调解分析，探讨种族（自变量）和测量结果（因变量）之间的关联是否可以部分或完全归因于 ADI（该模型中的调解人）的混杂。中介效应被测量为种族对 ADI 中介的感兴趣结果的总影响的百分比。多变量回归分析用于评估种族与 3 天或更多天的 LOS、非家庭出院处置、90 天住院患者再入院和 90 天 ED 入院之间的关联，同时调整年龄、性别、BMI、吸烟、CCI 和保险. 随后进行调解分析，探讨种族（自变量）和测量结果（因变量）之间的关联是否可以部分或完全归因于 ADI（该模型中的调解人）的混杂。中介效应被测量为种族对 ADI 中介的感兴趣结果的总影响的百分比。多变量回归分析用于评估种族与 3 天或更多天的 LOS、非家庭出院处置、90 天住院患者再入院和 90 天 ED 入院之间的关联，同时调整年龄、性别、BMI、吸烟、CCI 和保险. 随后进行调解分析，探讨种族（自变量）和测量结果（因变量）之间的关联是否可以部分或完全归因于 ADI（该模型中的调解人）的混杂。中介效应被测量为种族对 ADI 中介的感兴趣结果的总影响的百分比。随后进行调解分析，探讨种族（自变量）和测量结果（因变量）之间的关联是否可以部分或完全归因于 ADI（该模型中的调解人）的混杂。中介效应被测量为种族对 ADI 中介的感兴趣结果的总影响的百分比。随后进行调解分析，探讨种族（自变量）和测量结果（因变量）之间的关联是否可以部分或完全归因于 ADI（该模型中的调解人）的混杂。中介效应被测量为种族对 ADI 中介的感兴趣结果的总影响的百分比。

结果 

在 THA 组中，在针对年龄、性别、BMI、吸烟、CCI 和保险进行调整后，白人患者经历 3 天或更长时间 LOS 的几率较低（OR 0.43 [95% 置信区间 (CI) 0.31 至 0.59] ; p < 0.001) 和非家庭出院 (OR 0.39 [95% CI 0.27 to 0.56]; p < 0.001)。在中介分析中，ADI 部分解释（或中介）了 37% 的种族与 3 天或更长时间的 LOS 之间的关联（-0.043 [95% CI -0.063 至 -0.026]；p < 0.001）和 40% 的关联种族和非家庭排放（0.041 [95% CI 0.024 至 0.059]；p < 0.001）。然而，观察到种族与两种结果之间的直接关联较小（LOS 3 天或更长时间：-0.075 [95% CI -0.13 至 -0.024]；p = 0.004；非家庭出院：0.060 [95% CI 0.016 至 0.11]； p = 0.004）。在 THA 组中，未观察到种族与 90 天再入院或急诊入院之间存在关联。在 TKA 组中，在针对年龄、性别、BMI、吸烟、CCI 和保险进行调整后，白人患者经历 3 天或更长时间 LOS 的几率较低（OR 0.41 [95% CI 0.32 至 0.54]；p < 0.001 )、非在家出院（OR 0.44 [95% CI 0.33 至 0.60]；p < 0.001）、90 天再入院（OR 0.54 [95% CI 0.39 至 0.77]；p < 0.001）和 90 天 ED 入院（OR 0.60 [95% CI 0.45 至 0.79]；p < 0.001）。在中介分析中，ADI 介导了 19% 的种族与 3 天或更长时间的 LOS 之间的关联（-0.021 [95% CI -0.035 至 -0.007]；p = 0.004）和 38% 的种族与非家庭出院之间的关联（ 0.029 [95% CI -0.016 至 0.040]；p < 0.001），但种族与这些结果之间也存在直接关联（LOS 3 天或更长时间：-0. 088 [95% CI -0.13 至 -0.049]；p < 0.001；非家庭排放：0.046 [95% CI 0.014 至 0.078]；p = 0.006）。ADI 没有调解在 TKA 组中观察到的种族与 90 天再入院和 ED 入院之间的关联。

结论 

我们的研究结果表明，社会经济劣势可能与先前假设的初次全关节置换术后医疗保健利用参数的种族驱动差异的很大一部分有关。整形外科医生应尝试确定潜在可改变的社会经济劣势指标。这是呼吁骨科界采取行动，考虑采取具体干预措施来支持来自脆弱地区或收入较低的患者，例如支持非紧急医疗运输的申请或将患者转介给当地护理协调机构。未来的研究应该寻求确定哪些特定资源或方法可以改善社会经济劣势患者 TJA 后的结果。

证据等级 

III 级，治疗研究。