Risk factors influencing survival of acellular porcine corneal stroma in infectious keratitis: a prospective clinical study

Table 3 Possible risk factors for graft failure

Parameter	Therapeutic success (n = 27)	Graft failure (n = 12)	P	Type of statistical test
Indication for graft			0.046	Weighted log-rank test^b
Nonviral	24 (75.0%)	8 (25.0%)
Herpetic	3 (42.9%)	4 (57.1%)
Mean lesion size^a (mm)	4.81 ± 1.17 (2.78–7.34)	5.92 ± 1.00 (3.39–7.18)	0.007	t-test
Mean graft size (mm)	7.59 ± 0.21 (7.25–8.00)	7.95 ± 0.38 (7.25–8.5)	< 0.001	t-test
Graft size group			< 0.001	Log-rank test
< 8.0	25 (83.3%)	5 (16.7%)
≥ 8.0	2 (22.2%)	7 (77.8%)
Preoperative sterile hypopyon			0.198	Log-rank test
Absence	23 (65.7%)	12 (34.3%)
Presence	4 (100%)	0 (0%)

^aLesion size reported as the equivalent circular diameter
^bBecause of the presence of nonproportional hazards, the weighted log-rank test was used to compare the survival distributions between nonviral keratitis and herpetic keratitis groups. Fleming–Harrington weights of P = 0, q = 0.5 were set to emphasize differences occurring later in time

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