Disparities in kidney transplantation accessibility among immigrant populations in Europe: A systematic review and meta-analysis

Background and objectives: Disparities in access to healthcare for patients with an immigration background are well-known. The aim of this study was to determine whether disparities among immigrant populations translate into a relative difference in the number of kidney transplants (KT) performed in documented immigrant patients (first and second generation) relative to native-born patients in Europe. Methods: A literature search was performed in PubMed from inception to 11-10-2022. Studies were eligible if: (1) written in English, (2) included immigrant and native-born KT patients, (3) performed in countries registered as Council of Europe members, (4) focused on documented first- and second-generation immigrant populations [1]. Systematic reviews, literature reviews, and case reports or articles about emigration, non-KT, and undocumented immigrants were excluded. The outcome measurement was a relative percentage of KTs to the total population per 100.000 residents. By dividing the immigrant percentages by the native-born resident percentages, the odds ratio (OR) was calculated in a meta-analysis. The risk of bias was assessed; articles with high risk of bias were excluded in a second meta-analysis. Results: Out of 109 articles, 5 were included (n = 24,614). One Italian study (n = 24,174) had a ratio below 1, being 0.910 (95%CI 0.877-0.945). The other four articles (n = 196, n = 283, n = 77, n = 119) had ratios above 1: 1.36 (95%CI 0.980-1.87), 2.04 (95%CI 1.56-2.68), 2.23 (95%CI 1.53-3.25) and 2.64 (95%CI 1.68-4.15). After performing a meta-analysis, the OR did not show a significant difference: 1.68 (95%CI 1.03-2.75). After bias correction, this remained unchanged: 1.78 (95%CI 0.961-3.31). Conclusions: In our meta-analysis we did not find a significant difference in the relative number of KTs performed in immigrant versus native-born populations in Europe. However, a lesser likelihood for immigrants to receive a pre-emptive kidney transplantation was found. Large heterogeneity between studies (e.g. different sample size, patient origins, study duration, adult vs children patients) was a shortcoming to our analysis. Nevertheless, our article is the first review in this understudied topic. As important questions (e.g. on ethnicity, living donor rate) remain, future studies are needed to address them.