Table 2.

Results of meta-analysis by using different methods of dichotomising volume groups

	Lowest volume group vs all others	Even dichotomy, middle group as HV	Even dichotomy, middle group as LV (primary analysis)	Highest volume group vs all others
Mortality
Radical nephrectomy	OR: 0.82 95% CI 0.71 to 0.94, p=0.01	OR: 0.83 95% CI 0.72 to 0.95, p<0.01	OR: 0.74 95% CI 0.61 to 0.90, p<0.01	OR: 0.72 95% CI 0.61 to 0.85, p<0.01
Partial nephrectomy	OR: 0.48 95% CI 0.18 to 1.31, p=0.15	OR: 0.67 95% CI 0.17 to 2.75, p=0.58	OR: 0.84 95% CI 0.31 to 2.26, p=0.73	OR: 0.93 95% CI 0.31 to 2.77, p=0.90
Nephrectomy with venous thrombectomy	OR: 0.59 95% CI 0.35 to 0.99, p=0.045	OR: 0.46 95% CI 0.27 to 0.80, p<0.01	OR: 0.48 95% CI 0.29 to 0.81, p=0.01	OR: 0.48 95% CI 0.25 to 0.92, p=0.03
Complications
Radical nephrectomy	OR: 0.89 95% CI 0.78 to 1.01, p=0.07	OR: 0.84 95% CI 0.68 to 1.05, p=0.13	OR: 0.82 95% CI 0.73 to 0.92, p<0.01	OR: 0.82 95% CI 0.73 to 0.92, p<0.01
Partial nephrectomy	OR: 0.82 95% CI 0.55 to 1.41, p=0.60	OR: 0.80 95% CI 0.47 to 1.36, p=0.40	OR: 0.85 95% CI 0.55 to 1.30, p=0.44	OR: 0.81 95% CI 0.53 to 1.24, p=0.33

HV, high volume; LV, low volume.