Survival predictors of lung cancer patients in ICU: the importance of acute kidney injury prediction and prevention

Introduction

Patients with cancer may require intensive care unit (ICU) admission owing to complications or treatment-associated side effects (Koutsoukou, 2017; Martos-Benítez et al., 2020). The progression of cancer treatment and ICU management has significantly improved the survival outcomes of patients with cancer. Conversely, longer disease duration and treatment-related events have also increased the number of patients subjected to ICU care (Azoulay et al., 2017; Puxty et al., 2015). Lung cancer represents the most common cause of cancer-related mortality. Additionally, patients with lung cancer may exhibit higher risks of acute respiratory failure and bacterial infection (Cupp et al., 2018; Williams, Ford & Coopersmith, 2023). Therefore, lung cancer remains the most common cancer type among ICU-admitted patients, with solid tumors exhibiting the poorest prognosis (Zarogoulidis et al., 2013).

Previous studies have reported that the short-term mortality rate of ICU-admitted patients with solid tumors averaged approximately 20%–30% (Martos-Benítez, Soto-García & Gutiérrez-Noyola, 2018; Ostermann et al., 2017; Puxty et al., 2014). Studies in ICU-admitted patients with lung cancer have reported various results. A study in newly diagnosed patients with lung cancer who underwent ICU treatment revealed an overall mortality rate of approximately 18.7% (Park et al., 2021). Another study reported ICU and hospital mortality rates of 36% and 51%, respectively, among patients with lung cancer (Soubani & Ruckdeschel, 2011). An analysis of Medical Information Mart for Intensive Care III, a large-scale single-center database, revealed that ICU-admitted patients with lung cancer had 28-day in-hospital and 6-month mortality rates of 30.6% and 68.2%, respectively (Qian et al., 2023). For ICU-admitted patients with advanced or metastatic lung cancer who required mechanical ventilation, the 3-month mortality rate was as high as 67% (Barth et al., 2018).

Owing to the high risk of poor outcomes among ICU-admitted patients with lung cancer, identifying those with more probability to benefit from ICU admission and the timely recognition of prognostic signs during ICU management is crucial. Determining the predictors of these patients may help optimize the admission and treatment strategies. The prognostic characteristics of ICU-admitted patients with lung cancer remain not well elucidated. General factors that are correlated with worse outcomes encompass advanced oncologic disease, poor performance status, and signs of critical complications (Cuenca et al., 2022; Shen et al., 2022). Indicators noted in various studies lack consistency and are very limited in clinical practice (Adam & Soubani, 2008; Jennens et al., 2002; Soares et al., 2004; Zarogoulidis et al., 2013).

Acute kidney injury (AKI) is among the common complications of patients with cancer and has a profound influence on prognosis (Gupta, Gudsoorkar & Jhaveri, 2022). AKI has been suggested to be a significant prognostic factor for ICU patients (Alba Schmidt et al., 2024; Hashemian et al., 2016). Moreover, AKI has been reported to be a significant risk factor for the short-term mortality of ICU-admitted patients with cancer (Nazzal et al., 2022; Seylanova et al., 2020; Yuan et al., 2020). However, studies on AKI incidence and influence on ICU-admitted patients with lung cancer are very limited.

Using the data from a large-scale multicenter cross-sectional study of ICU-admitted patients with cancer, we analyzed the potential predictors of the short-term survival of patients admitted to the ICU. AKI was identified as a critical predictor for the short-term mortality of these patients.

Materials and Methods

Results

Discussion

Data obtained from the 37 ICUs of cancer-specialty hospitals revealed that 269 patients with lung cancer were admitted during the 2-month period. The 90-day mortality rate following ICU admission was 45.4%. Patients with 90-day mortality generally exhibited more severe conditions before admission, a higher number of ICU-related complications, and underwent more intense treatment than survivors. Despite its low recorded incidence, AKI was independently associated with ICU, in-hospital, and 90-day mortality outcomes in the multivariate analysis. Moreover, the condition severity at admission and ICU treatment choices, particularly anti-infection regimen, may be associated with a higher risk of AKI.

Previous studies have reported that the in-hospital and short-term mortalities of ICU-admitted patients with solid tumors varied, accounting for mortality rates of 20%–30% (Martos-Benítez, Soto-García & Gutiérrez-Noyola, 2018; Ostermann et al., 2017; Puxty et al., 2014). Although inconsistent results have been reported, it has been suggested that the mortality rate of lung cancer following ICU admission was higher than that of other solid tumors (Peng et al., 2021), reaching approximately 50% (Andréjak et al., 2011). Results from this study identified a 45.4% 90-day mortality rate, which is consistent with previous studies. These results confirm that ICU-admitted patients with lung cancer have higher mortality risks.

Various characteristics of admitted patients with lung cancer were identified as factors associated with short-term mortality. However, most of these factors were generally correlated with disease severity evaluation, and a clear pattern of predictors was difficult to recognize. Interestingly, in this study, increased BMI was suggested to be associated with better survival prognosis. This finding is not surprising, as higher BMI is associated with better nutrition and health status. In a previous study, a BMI cutoff of 25 kg/m² was suggested for the ICU admission evaluation of patients with cancer (Zarogoulidis et al., 2013). However, the average BMI of the study population was relatively higher than 24 kg/m²; therefore, increased BMI could be associated with a better prognosis. In this study, transfer sources were found to be associated with survival outcomes. Patients with cancer are typically admitted to the ICU due to oncology, treatment-related complications, or precautious postoperative care (Biskup et al., 2017). The source of transfer may be correlated with the severity of complications, indicating different prognostic risks. The choice of anti-infection regimen was correlated with survival outcomes. This finding can be attributed to two reasons. One finding is that the more intense treatment indicates more severe clinical conditions. Additionally, anti-infection regimens were primarily empirical, and certain medications may increase the risks of organ injuries. Previous studies have suggested an association between early empirical antifungal therapy and survival rates in patients with cancer (Kanj et al., 2022).

The results of this study indicate that AKI is significant in predicting adverse survival outcomes. AKI is a frequent complication of critical illness and in patients with cancer and is associated with worse survival outcomes (Córdova-Sánchez et al., 2021; Hoste et al., 2015; Kang et al., 2019; Seylanova et al., 2020). It has been suggested to be a key factor in risk stratification and predicting mortality in ICU patients (Huang et al., 2021; Libório et al., 2011; Wan et al., 2020; Wiersema et al., 2019). Previous studies have suggested that AKI timing onset and progression help to predict the outcomes of sepsis and in-hospital mortality (Wang et al., 2023). Recognition and prompt notification of AKI may help improve the outcomes of patients with critical illness (Atia et al., 2023). From a mechanistic perspective, AKI increased the risks of other adverse outcomes, including stroke, cardiovascular disease, and upper gastrointestinal hemorrhage (Fortrie, de Geus & Betjes, 2019). These results further suggested that AKI evaluation and prevention could serve as a critical strategy in the ICU admission and management of patients with lung cancer.

This study had some limitations. First, this study was conducted in a relatively short period and only in the ICUs of cancer-specialty hospitals, which may have caused the selection bias of patients. Moreover, owing to the nature of an observational study, the data quality should be further improved. For example, the incidence of ICU-associated AKI in this study was significantly lower than previously reported, and the data of corresponding treatment for AKI were missing. The small number of AKI events recorded may limit the certainty of the conclusion, and the small number of AKI events limited the analysis for the potential correlator analysis. Conversely, the statistically independent influence of AKI on mortality being detected even in this small sample size of events may further emphasize that AKI could be among the most critical predictors of prognosis in ICU-admitted patients with lung cancer. Furthermore, as the data were extracted from observational study records from the ICU, certain known prognostic factors, including staging and histological typing of cancer, and performance score were missing. These may introduce further uncertainty to the conclusion. Nevertheless, this study collected data with a relatively large sample size from multiple centers in China. These findings suggest that more large-scale population studies are warranted to clarify the predictors of survival outcomes following ICU care of patients with lung cancer.

Conclusions

The results of this study suggest that predictive tools are essential for ICU-admitted patients with lung cancer owing to their high mortality risks. AKI prediction and prevention should be prioritized in these patients.

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