Table 1.

Description of each study design and quality assessment using the Newcastle-Ottawa Quality Assessment Scale, listed by order of online publication date

Study	Study design	Selection	Comparability	Outcome
Manganaro et al.16	Single-center case series	☆☆★★	☆☆	☆☆☆
Boyarksy et al.18	Cross-sectional national survey	☆☆☆★	☆☆	☆☆☆
Pereira et al.21	Two-center case series	★☆★★	☆☆	⋆☆☆
Sánchez-Álvarez et al.12	National registry cohort	★★☆★	★☆	☆★☆
Vistoli et al.19	Cross-sectional national survey	★☆☆★	☆☆	☆☆☆
Rodriguez-Cubillo et al.23	Single-center case series	★☆★★	☆☆	★★★
Pascual. et al.13	National registry case series	★☆★★	☆☆	★☆☆
Chen et al.27	Single-center case series	★☆★★	☆☆	★★★
Mehta et al.28	Single-center case series	★☆★★	☆☆	★★★
Bossini et al.25	Multicenter case series	★☆★★	☆☆	★★★
Cravedi et al.17	Multicenter case series	★☆★★	☆☆	★★☆
Chaudhry et al.26	Multicenter case series	★☆★★	☆☆	★☆☆
Pérez-Sáez et al.14	National registry case series	★☆★★	☆☆	★★★
Demir et al.24	Multicenter case series	☆☆★★	☆☆	★☆☆
Lubetzky et al.22	Single-center case series	★☆★★	☆☆	★★★
Bell et al. (preprint)15	National registry case series	★☆★★	☆☆	★★★
Mohamed et al.20	Single-center case series	★☆★★	★☆	★★★
Kates et al.10	Multicenter case series	☆☆★★	☆☆	★★★
Benotmane et al.29	Single-center case series	★☆★★	☆☆	★★★
Ravanan et al.11	National registry cohort	★★★★	★☆	★★★

From left to right, quality items were starred black if they fulfilled predefined criteria: selection was starred on representativeness of patients with the exposure of interest (kidney transplant), selection of the nonexposed group, ascertainment of exposure, and demonstration that outcome of interest (death) was not present at start of the study; comparability was starred on the study controlling for the exposure of interest, and any additional factor; outcome was starred on how the outcome was assessed, whether follow-up was long enough for the outcome to occur, and whether loss to follow-up was adequate enough to be unlikely to introduce bias.