Associations of Hospital Unit Occupancy with Inpatient Falls and Fall-Risk Assessment Completion: A Retrospective Cohort Study.

Abstract

Background: Inpatient fall assessment and prevention efforts are primarily performed by nursing teams. Operating at high occupancy levels may therefore reduce the care team's ability to deliver these efforts in a timely and effective way. We investigated the associations of unit-level hospital occupancy with the rate of inpatient fall and the completion of patient fall-risk assessment.

Methods: We conducted a retrospective cohort study using data from a large teaching hospital network in Ontario, between 2017-2020. We used a multi-state semi-Markov model to represent the time from admission to inpatient care to primary outcomes of first inpatient fall, and completion of fall-risk assessment in the presence of other competing events. Unit-level occupancy was defined as the time-dependent maximum ratio of unit census to unit capacity and further categorized based on whether it was below or above a given threshold or "tipping point". We estimated the tipping point as well as the association between unit-level occupancy below and above the tipping point with the cause-specific hazard rate of each outcome, adjusting the estimates for confounders.

Results: The final cohort had 83,839 inpatient stays for the fall outcome and 83,853 inpatient stays for the fall-risk assessment outcome. Unit occupancy levels above the estimated tipping point of 95% were associated with an increased rate of falls [Hazard Ratio (HR): 2.10, 95% Confidence Interval (CI): 1.05, 4.20], whereas occupancy levels above the estimated tipping point of 77% were associated with a decreased rate of completion of fall-risk assessment [HR: 0.87, 95% CI: 0.82, 0.91].

Conclusions: Our study provides evidence for a significant increase in the rate of falls and decrease in the rate of assessment completion when occupancy levels exceed certain tipping points. The results motivate the design of safety protocols tailored for periods of high-capacity strain to support nursing teams and prioritize delivery of assessments and interventions to patients at high risk of fall.