Prediction of morbidity and mortality after early cholecystectomy for acute calculous cholecystitis: results of the S.P.Ri.M.A.C.C. study

Table 5 Internal (derivation group) and external (validation group) validation of 25 as POSSUM Physiological Score cutoff to select high-risk patients with acute calculous cholecystitis for early cholecystectomy

Outcome	Group	Derivation group (%)	p value	Validation group (%)	p value
In-hospital mortality	POSSUM PS < 25	0	< 0.001	0	0.003
In-hospital mortality	POSSUM PS > = 25	5	< 0.001	3	0.003
30-day mortality	POSSUM PS < 25	0	< 0.001	0	0.001
30-day mortality	POSSUM PS > = 25	6	< 0.001	4	0.001
In-hospital major morbidity	POSSUM PS < 25	4	< 0.001	3	0.002
In-hospital major morbidity	POSSUM PS > = 25	16	< 0.001	10	0.002
30-day major morbidity	POSSUM PS < 25	5	< 0.001	4	0.002
30-day major morbidity	POSSUM PS > = 25	19	< 0.001	11	0.002