Individual Organ Failure and Concomitant Risk of Mortality Differs According to the Type of Admission to ICU - A Retrospective Study of SOFA Score of 23,795 Patients

Abstract

Introduction: Organ dysfunction or failure after the first days of ICU treatment and subsequent mortality with respect to the type of intensive care unit (ICU) admission is poorly elucidated. Therefore we analyzed the association of ICU mortality and admission for medical (M), scheduled surgery (ScS) or unscheduled surgery (US) patients mirrored by the occurrence of organ dysfunction/failure (OD/OF) after the first 72h of ICU stay.

Methods: For this retrospective cohort study (23,795 patients; DIVI registry; German Interdisciplinary Association for Intensive Care Medicine (DIVI)) organ dysfunction or failure were derived from the Sequential Organ Failure Assessment (SOFA) score (excluding the Glasgow Coma Scale). SOFA scores were collected on admission to ICU and 72h later. For patients with a length of stay of at least five days, a multivariate analysis was performed for individual OD/OF on day three.

Results: M patients had the lowest prevalence of cardiovascular failure (M 31%; ScS 35%; US 38%), and the highest prevalence of respiratory (M 24%; ScS 13%; US 17%) and renal failure (M 10%; ScS 6%; US 7%). Risk of death was highest for M- and ScS-patients in those with respiratory failure (OR; M 2.4; ScS 2.4; US 1.4) and for surgical patients with renal failure (OR; M 1.7; ScS 2.7; US 2.4).

Conclusion: The dynamic evolution of OD/OF within 72h after ICU admission and mortality differed between patients depending on their types of admission. This has to be considered to exclude a systematic bias during multi-center trials.

Fig 1. Study protocol.

ICU length of stay ≥ 5 days, classifying patients according to the type of admission (percent of patients), followed by an evaluation of individual organ dysfunction/organ failure on ICU day three. ScS, scheduled surgery; US, unscheduled surgery; M, medical; SOFA; OD, organ dysfunction (SOFA score 1–2 points); OF organ failure (SOFA score 3–4 points).

Fig 2. Number of organ failure on admission and day 3.

Number of patients with n organ failure ad admission (rectangle); Number of patients with n organ failure on day 3 (triangle); ICU Mortality (mean group ± 95% CI) in respect to number of organ failure for 23,795 cases with an ICU length of stay of at least five days.

Fig 3. Organ failure on admission and day three of ICU treatment in the ScS-, the US- and the M-patients.

Bars depict the ICU mortality rate of each organ failure (group mean ± 95% CI). Mortality increased with an increasing number of organ failures while the same number of organ failures on day three had a higher mortality rate compared to the day of ICU admission for every type of admission. M patients had higher mortality rates than surgical admitted patients. Lines depict the number of cases with an organ failure. ScS, scheduled surgery; US, unscheduled surgery; M, medical patients; Adm, ICU Admission day; day 3, third day of ICU treatment.

Fig 4. Prevalence of Organ dysfunction and failure per organ at admission to ICU and at day 3.

Depicted are the prevalences (mean group ± 95% CI) of organ dysfunction (SOFA score 1–2 points) and organ failure (SOFA score 3–4 points) on admission and on day 3 of ICU in respect to the type of admission in patients with an ICU LOS of at least five days. M-patients had on admission to ICU and on day 3 less heart failure (B) and less coagulation dysfunction (D), but a higher proportion of respiratory (A) and renal failure (C) than the ScS and the US patients. ScS, scheduled surgery; US, unscheduled surgery; M, medical; Adm, admission to ICU; day 3 day 3 of ICU treatment; normal, individual organ SOFA score 0 points; dysfunction, individual organ SOFA score 1–2 points; failure, individual organ SOFA score 3–4 points.

Fig 5. Multivariate, forward stepwise logistic regression analysis with intensive care unit mortality as the dependent factor and OD/OF at day 3.

All data are adjusted to age, gender and organ dysfunction/organ failure at admission. Odds ratio is depicted in a logarithmic plotting (n = 23,795). In organ dysfunction only a significantly increased risk of death is observed in the M-patients with lung dysfunction. The highest risk of death is found in M-patients with cardiovascular or liver failure, as well as in ScS patients with liver or renal failure. In US-patients renal failure was accompanied with the highest risk of death. OR, odds ratio; CI, confidence interval; OD, organ dysfunction; OF, organ failure; CV, cardiovascular; ScS, scheduled surgery; US, unscheduled surgery; M, medical.