Table 2.

Outcomes of the subgroup analysis

Subgroup	Early AVF failure	12-months primary patency
Overall	0.56 (0.37–0.84)	1.33 (1.19–1.47)
Study location
Europe	0.59 (0.32–1.08)	1.35 (1.12–1.63)
Asia	0.57 (0.30–1.09)	1.22 (1.12–1.31)
North America	–	1.55 (1.32–1.82)
South America	0.33 (0.17–0.67)	–
P value for subgroup effect	0.757	0.351
Sample size
≤ 150 patients	0.46 (0.24–0.88)	1.22 (0.99–1.50)
> 150 patients	0.62 (0.37–1.06)	1.34 (1.19–1.51)
P value for subgroup effect	0.468	0.590
Year of publication
≤ 2010	0.45 (0.32–0.64)	1.33 (1.14–1.55)
> 2010	0.75 (0.40–1.39)	1.33 (1.16–1.52)
P value for subgroup effect	0.091	0.964
Study design
Cohort study	0.83 (0.50–1.38)	1.34 (1.19–1.51)
Randomized controlled trial	0.37 (0.25–0.54)	1.26 (1.02–1.56)
P value for subgroup effect	0.013	0.744
Risk of bias
Low	0.62 (0.27–1.40)	1.15 (0.99–1.35)
Moderate	0.49 (0.28–0.86)	1.31 (1.18–1.46)
Serious	0.69 (0.36–1.31)	1.48 (1.00–2.19)
P value for subgroup effect	0.783	0.412

Routine ultrasound examination is compared to physical examination (reference group). Data presented as risk ratio (95% confidence intervals). Bold text indicates statistical significance

AVF arteriovenous fistula