Multidimensional assessment of hand hygiene compliance and its association with healthcare-associated infection incidence in intensive care units

Background Previous studies have reported heterogeneous associations between average hand hygiene (HH) compliance and healthcare-associated infection (HAI) incidence, suggesting that monthly mean compliance alone may not fully characterize clinically relevant patterns of HH performance. We aimed to evaluate whether complementary metrics derived from the same HH dataset could provide additional contextual information on the relationship between HH performance and HAI incidence. Methods We conducted a prospective observational study using HH audit data collected across three intensive care units with differing operational and staffing profiles. Monthly HAI incidence data were obtained from a parallel prospective surveillance program conducted by the same infection prevention team. Monthly HH performance was characterized using predefined metrics representing overall compliance level, day-to-day variability, critical low-compliance episodes, and lower-tail performance. These included weighted monthly HH compliance, coefficient of variation, the proportion of critical HH days defined as observed days with daily compliance below 40%, and the 25th percentile of daily compliance values. Associations with HAI incidence were explored using correlation analyses. Results Weighted monthly HH compliance demonstrated the strongest pooled inverse association with HAI incidence. Complementary metrics reflecting day-to-day variability, critical low-compliance days, and lower-tail performance were also associated with HAI incidence, although their relative informativeness differed across units. These findings suggest that average compliance remains an important surveillance metric, while additional metrics may help characterize operational instability and episodes of distinctly poor HH performance. Conclusions Average HH compliance remains an informative surveillance metric and should not be replaced by complementary indicators. However, measures reflecting day-to-day variability, critical low-compliance days, and lower-tail performance may provide additional operational context for interpreting HH surveillance data. Incorporating multiple HH performance dimensions may support more targeted infection prevention and workforce-management strategies.