Predictors of in-ICU Mortality among Older Patients with Healthcare-Associated Infection: A Cohort Study

Background: Deaths occur frequently in intensive care units (ICUs), especially in older adults, and healthcare-associated infections (HCAIs) can increase mortality risk in this age range. Identifying the underlying factors that lead to HCAI is crucial for preventing and mitigating the risk of premature deaths. Objectives: This study aimed to identify predictors of in-ICU mortality among older adult patients with HCAI. Methods: This prospective cohort study was conducted in two general hospitals in Tehran, Iran, where 461 individuals aged 60 years and older were meticulously observed over a 6-month in March 2021. Mortality was considered the outcome, and the Apache II questionnaire, the frailty index, and demographic information were completed. The data were analyzed using binary logistic regression with a significance level of P < 0.05. Results: Older adult patients with HCAI had a 77% death rate out of 461 eligible individuals. Half of HCAIs were reported as ventilator-associated pneumonia. The most significant death percentages were observed in Klebsiella (37%) and Acinetobacter (21%). Ventilator-associated pneumonia (OR = 50.90, CI = 1.22 - 214.95), frailty status (OR = 45.94, CI = 17.51 - 120.52), COVID-19 (OR = 2.87, CI = 1.24 - 6.66), Apache-II (OR = 1.192, CI = 1.13 - 1.25) and length of hospital stays (OR = 1.05, CI = 1.02 - 1.07) significantly predicted mortality in older adult patients with HCAI. Conclusions: The mortality of older adults with HCAI is affected by factors such as Ventilator-associated pneumonia, frailty, COVID-19, disease severity, and length of hospital stay. Identifying risk factors for mortality is helpful for treatment planning, resource allocation, and identifying at-risk patients.