Pressure ulcers in secondary care: incidence, prevalence, and relevance.

Objective: To compare point and period prevalence rates.

Design: Descriptive, cohort, cross-sectional survey.

Participants: From a cohort of 25,075 cases, information on pressure ulcer status on admission was recorded for 20,283 cases. From 3237 selected cases, the pressure ulcer team made 2234 assessments.

Main Outcome Measures: Point prevalence, period prevalence, and incidence rates.

Main Results: The cohort showed a period prevalence rate of 1.4% and an incidence rate of 0.6%. Patients with a pressure ulcer were older, were more likely to have had surgery, had longer hospital stays, and had a higher cost weight. The cross-sectional survey revealed a point prevalence rate of 5.3%. Patients within the cross-sectional survey had longer lengths of stay, were more likely to have had surgery, and presented a higher cost weight in comparison with the cohort.

Conclusions: In an unselected hospital sample one can expect a period prevalence rate of 2% and a point prevalence rate of 10%. As demonstrated by the present study, differences between the 2 prevalence measurements are mainly due to the confounding of point prevalence rates by length of stay. Length of stay determines the probability of inclusion in a cross-sectional study and should be considered in pressure ulcer trials in the future.