Table 3.

Incidence rate of wound closure

Type of ulcer	Group	No of patients	Person‐years	No of events	Event rates per 100 person year
All ulcers	non‐NPWT	171	274·36	118	43·01 (35·91–51·51)
	NPWT	171	131·47	119	90·51 (75·63–108·32)
All ulcers by grade
Grade I	non‐NPWT	67	77·41	51	65·88 (50·07–86·69)
	NPWT	85	56·51	61	107·95 (83·99–138·74)
Grade II	non‐NPWT	100	194·41	65	33·43 (26·22–42·63)
	NPWT	85	74·96	58	77·96 (59·81–100·08)
Type of ulcers
Diabetic ulcers	non‐NPWT	118	205·65	80	38·9 (31·25–48·43)
	NPWT	140	112·01	94	83·92 (68·56–102·72)
Arterial ulcers	non‐NPWT	59	102·89	37	35·96 (26·05–49·63)
	NPWT	114	99·54	78	78·36 (62·56–97·83)
Venous ulcers	non‐NPWT	18	30·69	14	45·62 (27·02–77·03)
	NPWT	15	7·79	12	154·04 (87·48–271·24)
Pressure ulcers	non‐NPWT	17	16·77	13	77·52 (45·01–133·51)
	NPWT	23	11·96	17	142·14 (88·36–228·65)

NPWT, negative pressure wound therapy.