Table 2. Results of Random Effects Analysis: Risk Ratio for Each Clinical Risk Factor for Local Recurrence, Nodal Metastasis, and Disease-Specific Death.

Risk factor	Risk ratio (95% CI)	P value	Studies, No.	I2statistic, %
Local recurrence
HIV	7.0 (2.1-23.1)	.001	2	0
Organ transplantation	4.0 (2.2-7.0)	<.001	4	5
Chronic lymphocytic leukemia	3.8 (1.5-9.8)	.005	1	0
Age >65 y	2.3 (0.5-9.9)	.26	1	0
Tumor on ear or lip	2.0 (0.6-6.8)	.26	1	0
Tumor on head or neck	1.9 (0.9-3.9)	.09	5	0
Ulceration	1.7 (1.2-2.4)	.001	4	0
Tumor on scalp	1.7 (0.8-3.6)	.21	3	0
Age >70 y	1.6 (0.5-5.0)	.46	2	0
Tumor on ear	1.5 (0.8-3.1)	.23	6	0
Immunosuppression	1.5 (1.1-2.2)	.03	14	0
Growth rate ≥4 mm/mo	1.4 (0.5-4.1)	.50	1	0
Tumor on lip	1.4 (0.6-3.6)	.45	4	0
Male sex	1.2 (0.9-1.6)	.13	10	0
Age >60 y	1.0 (0.4-2.9)	.96	1	0
Age >75 y	0.9 (0.5-1.5)	.91	3	9
Nodal metastasis
Organ transplant	38.6 (21.2-70.3)	<.001	2	0
Chronic lymphocytic leukemia	4.5 (2.1-9.5)	<.001	1	0
Hypothyroidism	4.0 (2.8-5.7)	<.001	1	0
Age >65 y	3.9 (1.7-8.9)	.001	1	0
Growth rate ≥4 mm/mo	3.2 (1.1-9.7)	.04	1	0
Tumor on ear or lip	2.9 (1.4-5.9)	.003	1	0
HIV	2.8 (0.8-10.3)	.11	1	0
Age >70 y	2.7 (1.4-5.0)	.003	1	0
Immunosuppression	2.6 (2.2-3.0)	<.001	8	17
Tumor on scalp	2.5 (1.3-4.6)	.004	4	0
Tumor on lip	2.3 (1.4-3.9)	.002	6	5
Hematologic malignant tumor	2.1 (0.4-11.3)	.38	1	0
Diabetes	1.8 (0.3-12.1)	.53	1	0
Tumor on ear	1.8 (1.4-2.2)	<.001	9	12
Male sex	1.5 (1.1-1.9)	.002	8	3
Tumor on head or neck	1.3 (0.9-2.0)	.14	4	0
Age >75 y	1.3 (0.3-5.9)	.76	2	0
Smoking history	1.1 (0.7-1.7)	.75	1	0
Disease-specific death
Tumor on head or neck	4.4 (1.6-12.2)	.005	1	0
Organ transplant	4.1 (0.7-24.2)	.12	1	0
Immunosuppression	2.7 (1.6-4.5)	<.001	9	36
Ulceration	2.2 (1.2-4.1)	.01	1	0
Male sex	1.8 (0.4-8.6)	.45	3	0
Tumor on ear	1.4 (0.5-3.9)	.58	2	8
Tumor on lip	1.0 (0.7-1.3)	.94	2	0
Tumor on ear or lip	0.9 (0.2-3.8)	.90	1	0
Age >65 y	0.5 (0.2-1.1)	.10	1	0