Unit-level time trends and seasonality in the rate of hospital-acquired pressure ulcers in US acute care hospitals.

Abstract

This is a longitudinal study of the trend and seasonality in unit-level hospital-acquired pressure ulcer (HAPU) rates from 2004 to 2011, for 5447 acute care nursing units in 733 US hospitals. Unit-level HAPU rates decreased significantly during 2004-2007 (OR = 0.91, 95% CI [0.90, 0.91]) and the decreasing trend was much stronger during 2008-2011 (OR = 0.84 [0.83, 0.85]). Seasonal variations in HAPU rates were strong and consistent during 2004-2008, with the highest HAPU rate in Quarter 1 (Jan-Mar) and the lowest rate in Quarter 3 (Jul-Sep). During 2009-2011, the magnitude of this seasonality was greatly reduced, and only HAPU rate in Quarter 1 remained significantly higher than HAPU rates in other quarters.