Table 2. Summary of meta-analysis results for the numbers of dissected lymph nodes and bladder cancer outcomes.

Analysis specification	Highest category vs. lowest category
	Studies	SRRE (95% CI)	p−het	I2
Overall survival
All	13	0.72 (0.64−0.80)	0.000	67.2
Year of publication
≥ 2011	9	0.75 (0.66−0.84)	0.000	71.7
< 2011	4	0.61 (0.49−0.76)	0.663	0.0
Sample size (cases)
≥ 500	8	0.74 (0.67−0.83)	0.003	68.0
< 500	5	0.66 (0.48−0.91)	0.029	62.8
Mean age (years)
≥ 65	10	0.72 (0.64−0.81)	0.000	69.8
< 65	3	0.76 (0.53−1.11)	0.052	66.2
Geographical region
America	7	0.74 (0.69−0.80)	0.539	0.0
Europe	1	0.63 (0.46−0.87)	/	/
Asia	3	0.68 (0.40−1.16)	0.009	78.8
Cancer-specific survival
All	14	0.66 (0.54−0.80)	0.000	73.3
Year of publication
≥ 2011	6	0.79 (0.65−0.95)	0.011	66.6
< 2011	8	0.53 (0.37−0.75)	0.003	67.9
Sample size (cases)
≥ 500	6	0.74 (0.59−0.93)	0.001	75.3
< 500	8	0.57 (0.41−0.80)	0.002	68.3
Mean age (years)
≥ 65	10	0.75 (0.61−0.93)	0.001	69.1
< 65	3	0.56 (0.42−0.75)	0.271	23.5
Geographical region
America	6	0.62 (0.49−0.79)	0.004	70.7
Europe	3	0.91 (0.62−1.34)	0.016	75.7
Asia	6	0.49 (0.29−0.84)	0.010	70.1
Recurrence-free survival
All	9	0.64 (0.50−0.82)	0.000	72.5
Year of publication
≥ 2011	5	0.67 (0.47−0.96)	0.000	80.1
< 2011	4	0.58 (0.37−0.89)	0.029	66.7
Sample size (cases)
≥ 500	4	0.65 (0.53−0.80)	0.158	42.3
< 500	5	0.59 (0.34−1.03)	0.000	82.9
Mean age (years)
≥ 65	7	0.63 (0.51−0.78)	0.038	55.0
< 65	2	0.74 (0.21−2.55)	0.000	93.2
Geographical region
America	5	0.53 (0.36−0.77)	0.006	72.3
Europe	1	0.70 (0.56−0.88)	/	/
Asia	2	0.59 (0.09−4.06)	0.016	82.7

SRRE: summary relative risk estimate.