Table 4. Subgroup and sensitivity analysis of the prophylactic effect of GTN on the incidence of PEP.

Subgroup	Patients	RR (95%CI)	Z	P	Heterogeneity
					x2	I2	P
Topical route	184	1.00 [0.28, 3.53]	0.00	1.00	0.61	0%	0.43
Sublingual route	407	0.47 [0.28, 0.78]	2.93	0.003	0.79	0%	0.68
Transdermal route	1596	0.78 [0.55, 1.10]	1.42	0.16	6.22	36%	0.18
Low incidences of PEP	1638	0.88 [0.62, 1.26]	0.69	0.49	3.80	0%	0.58
High incidences of PEP	757	0.48 [0.32, 0.71]	3.63	0.00003	2.16	0%	0.71
Excluded one study[22]	2291	0.66 [0.51, 0.86]	3.08	0.002	9.69	7%	0.38
Excluded two studies[22,26]	2217	0.69 [0.53, 0.90]	2.71	0.007	8.15	2%	0.42