Annual frequency of hospitalizations classified as prolonged length-of-stay (PLOS) from 2000–2017.

(A) The vertical, gray bars represent the annual percentage of hospitalization events classified as PLOS. The percentage increased from 2.4% in 2000 to 7.6% in 2007, then declined slightly in the ensuing years and remained stable during 2009–2016 with a later peak in 2017. The black, dotted line, summarizes the annual median length-of-stay (LOS) in days across time, during the study period. The median LOS for all hospitalization events was 8 days in 2000, peaked at 10 days in 2006 and 2007 and then declined to 8 days afterwards and up to 2015, when it declined again by one day (B). The black, vertical, boxplots illustrate the annual adjusted odds ratios (aORs) for prolonged stay of hospitalization (PLOS) using 2000 as the year of reference. We used multinomial logistic regression models to control for age, gender, type of admission, recent hospital discharge, weekday/weekend admission, additional diagnoses, place of residence and socioeconomic status, using inverse probability weights based on diagnosis of admission. The adjusted risk of PLOS increased between 2000 and 2007, then substantially and continuously decrease afterwards despite a sustained percentage of PLOS episodes after 2008.