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Table 3 Subgroup analysis of included studies about PD-L1 and OS in this meta-analysis

From: The prognostic significance of PD-L1 and PD-1 expression in patients with nasopharyngeal carcinoma: a systematic review and meta-analysis

Subgroup No. of studies No. of patients HR (95% CI) p value Heterogeneity Statistical model used
I2 (%) p value
Cut-off value for PD-L1 positive
 ≥ 5% 5 606 0.98 (0.70, 1.35) 0.89 0 0.77 Fixed
 ≥ 1% 2 217 0.83 (0.50, 1.37) 0.47 0 0.59 Fixed
Detection area
 Tumor cells 10 1561 1.55 (0.99, 2.42) 0.06 79 0.000 Random
 Immune cells 3 483 0.68 (0.47, 0.99) 0.04 0 0.57 Fixed
 TC or IC 2 275 0.82 (0.51, 1.31) 0.40 0 1.00 Fixed
Calculation of HRs
 Multivariate 9 1558 1.40 (0.93, 2.10) 0.11 81 0.000 Random
 Univariate 9 1146 1.06 (0.58, 1.91) 0.86 79 0.000 Random
Estimation method of HRs
 Reported 10 1604 1.37 (0.92, 2.03) 0.12 79 0.000 Random
 K–M curve 3 342 3.12 (0.49, 19.83) 0.23 88 0.000 Random
  1. HRs: hazard ratios; IC: immune cells; K–M curve: Kaplan–Meier curve; No: number; OS: overall survival; TC: tumor cells; 0.000, P < 0.001