Background 

Income-based differences in the use of and outcomes in TKA have been studied; however, it is not known if different healthcare systems affect this relationship. Although Canada’s single-payer healthcare system is assumed to attenuate the wealth-based differences in TKA use observed in the United States, empirical cross-border comparisons are lacking.

Questions/purposes 

(1) Does TKA use differ between Pennsylvania, USA, and Ontario, Canada? (2) Are income-based disparities in TKA use larger in Pennsylvania or Ontario? (3) Are TKA outcomes (90-day mortality, 90-day readmission, and 1-year revision rates) different between Pennsylvania and Ontario? (4) Are income-based disparities in TKA outcomes larger in Pennsylvania or Ontario?

Methods 

We identified all patients hospitalized for primary TKA in this cross-border retrospective analysis, using administrative data for 2012 to 2018, and we found a total of 161,244 primary TKAs in Ontario and 208,016 TKAs in Pennsylvania. We used data from the Pennsylvania Health Care Cost Containment Council, Harrisburg, PA, USA, and the ICES (formally the Institute for Clinical Evaluative Sciences), Toronto, Ontario, Canada. We linked patient-level data to the respective census data to determine community-level income using ZIP Code or postal code of residence and stratified patients into neighborhood income quintiles. We compared TKA use (age and gender, standardized per 10,000 population per year) for patients residing in the highest-income versus the lowest-income quintile neighborhoods. Similarly secondary outcomes 90-day mortality, 90-day readmission, and 1-year revision rates were compared between the two regions and analyzed by income groups.

Results 

TKA use was higher in Pennsylvania than in Ontario overall and for all income quintiles (lowest income quartile: 31 versus 18 procedures per 10,000 population per year; p < 0.001; highest income quartile: 38 versus 23 procedures per 10,000 population per year; p < 0.001). The relative difference in use between the highest-income and lowest-income quintile was larger in Ontario (28% higher) than in Pennsylvania (23% higher); p < 0.001. Patients receiving TKA in Pennsylvania were more likely to be readmitted within 90 days and were more likely to undergo revision within the first year than patients in Ontario, but there was no difference in mortality at 1 year. When comparing income groups, there were no differences between the countries in 90-day mortality, readmission, or 1-year revision rates (p > 0.05).

Conclusion 

These results suggest that universal health insurance through a single-payer may not reduce the income-based differences in TKA access that are known to exist in the United States. Future studies are needed determine if our results are consistent across other geographic regions and other surgical procedures.

Level of Evidence 

Level III, therapeutic study.

中文翻译：

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在单一付款人系统中，TKA 使用和结果中基于收入的差异是否会减少？美国和加拿大的大数据库比较

背景 

研究了全膝关节置换术的使用和结果中基于收入的差异；然而，尚不清楚不同的医疗保健系统是否会影响这种关系。尽管加拿大的单一支付者医疗保健系统被认为可以减弱在美国观察到的全膝关节置换术使用中基于财富的差异，但缺乏实证跨境比较。

问题/目的 

(1) 美国宾夕法尼亚州和加拿大安大略省之间的 TKA 使用有何不同？(2) 在 TKA 使用中基于收入的差异在宾夕法尼亚州还是安大略省更大？(3) 宾夕法尼亚州和安大略省的 TKA 结果（90 天死亡率、90 天再入院率和 1 年翻修率）是否不同？(4) 宾夕法尼亚州或安大略省基于收入的全膝关节置换术结果差异是否更大？

方法 

我们使用 2012 年至 2018 年的管理数据，在这项跨境回顾性分析中确定了所有因初次 TKA 住院的患者，发现安大略省总共有 161,244 例初次 TKA，宾夕法尼亚州共有 208,016 例 TKA。我们使用的数据来自美国宾夕法尼亚州哈里斯堡的宾夕法尼亚州医疗保健成本控制委员会和加拿大安大略省多伦多市的 ICES（原临床评估科学研究所）。我们将患者层面的数据与相应的人口普查数据联系起来，使用邮政编码或居住邮政编码确定社区层面的收入，并将患者分层为社区收入五分位数。我们比较了居住在最高收入和最低收入五分位社区的患者的 TKA 使用情况（年龄和性别，每年每 10,000 人的标准化）。同样，对两个地区的次要结局 90 天死亡率、90 天再入院率和 1 年翻修率进行了比较，并按收入组进行了分析。

结果 

宾夕法尼亚州整体和所有收入五分位数的 TKA 使用率均高于安大略省（最低收入四分位数：每年每 10,000 人 31 例与 18 例手术；p < 0.001；最高收入四分位数：每年每 10,000 人 38 例与 23 例手术；p < 0.001）。安大略省最高收入和最低收入五分位数之间的使用相对差异（高出 28%）比宾夕法尼亚州（高出 23%）更大；p < 0.001。与安大略省的患者相比，宾夕法尼亚州接受 TKA 的患者更有可能在 90 天内再次入院，并且在第一年内接受翻修的可能性更大，但 1 年死亡率没有差异。比较收入组时，各国之间的 90 天死亡率、再入院率或 1 年翻修率没有差异 (p > 0.05)。

结论 

这些结果表明，通过单一付款人提供的全民健康保险可能不会减少美国已知存在的基于收入的 TKA 获取差异。未来的研究需要确定我们的结果在其他地理区域和其他外科手术中是否一致。

证据水平 

III级，治疗研究。