Characteristics and outcomes of frail patients with suspected infection in intensive care units: a descriptive analysis from a multicenter cohort study

Background: Frailty is associated with morbidity and mortality in patients admitted to intensive care units (ICUs). However, the characteristics of frail patients with suspected infection remain unclear. We aimed to investigate the characteristics and outcomes of frail patients with suspected infection in ICUs. Methods: This is a secondary analysis of a multicenter cohort study, including 22 ICUs in Japan. Adult patients (aged ≥16 years) with newly suspected infection from December 2017 to May 2018 were included. We compared baseline patient characteristics and outcomes among three frailty groups based on the Clinical Frailty Scale (CFS) score: fit (score, 1–3), vulnerable (score, 4), and frail (score, 5–9). We conducted subgroup analysis of patients with sepsis defined as per Sepsis-3 criteria. We also produced Kaplan–Meier survival curves for 90-day survival. Results: We enrolled 650 patients with suspected infection, including 599 (92.2%) patients with sepsis. Patients with a median CFS score of 3 (interquartile range [IQR] 3–5) were included: 337 (51.8%) were fit, 109 (16.8%) were vulnerable, and 204 (31.4%) were frail. The median patient age was 72 years (IQR 60–81). The Sequential Organ Failure Assessment scores for fit, vulnerable, and frail patients were 7 (IQR 4–10), 8 (IQR 5–11), and 7 (IQR 5–10), respectively (p = 0.59). The median body temperatures of fit, vulnerable, and frail patients were 37.5 °C (IQR 36.5 °C–38.5 °C), 37.5 °C (IQR 36.4 °C–38.6 °C), and 37.0 °C (IQR 36.3 °C–38.1 °C), respectively (p < 0.01). The median C-reactive protein levels of fit, vulnerable, and frail patients were 13.6 (IQR 4.6–24.5), 12.1 (IQR 3.9–24.9), 10.5 (IQR 3.0–21.0) mg/dL, respectively (p < 0.01). In-hospital mortality did not statistically differ among the patients according to frailty (p = 0.19). Kaplan–Meier survival curves showed little difference in the mortality rate during short-term follow-up. However, more vulnerable and frail patients died after 30-day than fit patients; this difference was not statistically significant (p = 0.25). Compared with the fit and vulnerable groups, the rate of home discharge was lower in the frail group. Conclusion: Frail and vulnerable patients with suspected infection tend to have poor disease outcomes. However, they did not show a statistically significant increase in the 90-day mortality risk.