Improving the quality of pressure ulcer care with prevention: a cost-effectiveness analysis.

To the Editor: Padula et al 1 address an important patient safety issue but the analysis contains assumptions that are not consistent with existing data. The untenable assumptions pertain to patient population, model structure, and the prevention program they evaluated. First, the authors simulated a patient cohort with an assumed average of 56 years of age. As we understand it, the burden of pressure ulcers is more pronounced in older patients. According to 1 set of national estimates, patients with hospitalacquired pressure ulcers are on average 71.9 years of age and overall, the mean age of all inpatients is 61.5 years. The model structure allows reverse staging, namely allowing a transition from stage 3 to 4 pressure ulcers to stage 1 to 2 pressure ulcers. According to a position statement on reverse staging by the National Pressure Ulcer Advisory Panel, pressure ulcers heal to progressively more shallow depth, they do not replace lost muscle, subcutaneous fat, or dermis before they re-epithelialize. Also, stage 2 pressure ulcers (eg, a loss of partial thickness of skin appearing as an abrasion, blister, or shallow crater) are typically treated, whereas stage 1 (eg, persistent redness of skin) are often not reported reliably, and naturally healed. Consequently, these 2 stages are not typically considered as a single entity. The authors assumed an odds ratio for the prevention effect estimate on pressure ulcer incidence, citing a literature review of observational studies. A large body of clinical evidence from 52 randomized controlled trials included in a systematic review of prevention by Reddy et al in 2006 for which the authors cited was not perused at all as input to the analysis. We are interested in the association between the above assumptions and the projected cost-effectiveness. How could a prevention program of pressure ulcers in 1 single episode of hospitalization lead to a mortality rate of 15.1% with prevention and 29.5% without prevention, and a lifetime health benefit with prevention of approximately 2 QALYs?