Statistical Analysis
All statistical analyses were carried out on Comprehensive Meta-Analysis
software (version 3.3.070, Biostat Inc, New Jersey, USA).
P<0.05 was considered statistically significant.
The pooled HRs for PFS and OS were
calculated to evaluate the effect of PPIs exposure on ICIs therapy
compared to non-PPIs users. The pooled HR>1.0 indicated an
adverse influence of PPIs exposure undergoing ICIs therapy.
HR<1.0 denoted a
beneficial influence of PPIs
exposure undergoing ICIs therapy.
The χ2-based Q
test and I2 statistic were applied to detect and
quantize heterogeneity (18, 19). I2>50%
(I2 <25%: no heterogeneity;
I2 = 25–50%: moderate heterogeneity;
I2 >50%: large heterogeneity) and/or P
<0.1 for Q test represented statistically significant
heterogeneity, in this situation, the random model was used, in other
cases, fixed models were applied. We use funnel plot and Egger’s test as
well as Begg’s test to detect publication bias. Publication bias is
suspected if p<0.05 for the Egger’s and Begg’s tests(20, 21).
Sensitivity analysis were conducted using one study removed to assess
stability of pooled outcome of HR.