Table 3.

APU Rates and Relative Rates, by Care Setting

Care Setting	Number of Patients with APUs	Person- Days at Risk	APU Rate per 100 Person-Days (95% CI)	Relative Rate (95% CI), Model 1 (n=658)	Relative Rate (95% CI), Model 2 (n=619)	Relative Rate (95% CI), Model 3 (n=614)	Relative Rate (95% CI), Model 4 (n=614)
Acute hospital	96	1984	4.8 (4.0–5.9)	8.6 (5.6–13.3)	6.2 (4.0–9.5)	4.1 (2.5–6.7)	2.2 (1.3–3.7)
Rehabilitation	18	1457	1.2 (0.8–2.0)	2.2 (1.4–3.6)	2.2 (1.3–3.4)	1.9 (1.1–3.1)	1.4 (0.8–2.3)
Nursing home	81	5405.5	1.5 (1.2–1.9)	2.7 (1.7–4.1)	2.1 (1.4–3.3)	1.5 (0.9–2.4)	1.3 (0.8–2.1)
Home	6	1072	0.6 (0.2–1.2)	1 (reference)	1 (reference)	1 (reference)	1 (reference)
Re-admission to acute hospital	7	236.5	3.0 (1.3–6.1)	5.3 (3.0–9.3)	4.0 (2.2–7.1)	2.2 (1.1–4.2)	2.2 (1.1–4.2)

Notes: APU=acquired pressure ulcer

Model 1: Unadjusted

Model 2: Adjusted for baseline covariates (age, sex, Mini-Mental State Exam score, pre-admission residence, incontinence, history of chronic cognitive deficit, nutritional risk, body mass index, activity level, presence of pre-existing pressure ulcers, Rand Sickness at Admission score, Charlson Comorbidity Index score, albumin level, arterial insufficiency, and admission hospital)

Model 3: Adjusted for baseline covariates and time-dependent covariates (acute mental status, activity level, and incontinence)

Model 4: Adjusted for baseline covariates, time-dependent covariates, and days since initial hospital admission