Table 4.

Comparison of the median number of procedures and hospitalization days between the UVPR and PVPR groups with effect size (r) and p-value.

Variable	Effect size (r)	p-value
Number of VPR with complications	0.408	<0.0001
Number of VPR without complications	0.530	<0.0001
Days of hospitalization due to complications	0.387	<0.0001

Effect size (r) was calculated based on the Mann–Whitney U test, using the formula r = Z/√N, where Z is the Z-score from the Mann–Whitney U test, and N is the total number of observations. Interpretation of r: small effect = 0.1, medium effect = 0.3, large effect ≥ 0.5. Significance level set at α = 0.05.VPR, voice prosthesis replacement; UVPR, unscheduled voice prosthesis replacement; PVPR, prophylactic voice prosthesis replacement.