TNF and obstructive sleep apnea syndrome: The forest plot outcome indicated that CPAP therapy would lower the TNF-α levels in OSAHS patients, with a weighted mean difference (WMD) of 1.08 (95% CI: 0.62–1.55; P < 0.001) based on the REM since there is highly significant heterogeneity (I2 = 90%) among the studies.