Usefulness of the CONUT index upon hospital admission as a potential prognostic indicator of COVID-19 health outcomes

Abstract

Background: In-hospital mortality in patients with coronavirus disease 2019 (COVID-19) is high. Simple prognostic indices are needed to identify patients at high-risk of COVID-19 health outcomes. We aimed to determine the usefulness of the CONtrolling NUTritional status (CONUT) index as a potential prognostic indicator of mortality in COVID-19 patients upon hospital admission. Methods: Our study design is of a retrospective observational study in a large cohort of COVID-19 patients. In addition to descriptive statistics, a Kaplan–Meier mortality analysis and a Cox regression were performed, as well as receiver operating curve (ROC). Results: From February 5, 2020 to January 21, 2021, there was a total of 2969 admissions for COVID-19 at our hospital, corresponding to 2844 patients. Overall, baseline (within 4 days of admission) CONUT index could be scored for 1627 (57.2%) patients. Patients’ age was 67.3 ± 16.5 years and 44.9% were women. The CONUT severity distribution was: 194 (11.9%) normal (0–1); 769 (47.2%) light (2–4); 585 (35.9%) moderate (5–8); and 79 (4.9%) severe (9–12). Mortality of 30 days after admission was 3.1% in patients with normal risk CONUT, 9.0% light, 22.7% moderate, and 40.5% in those with severe CONUT ( P < 0.05). An increased risk of death associated with a greater baseline CONUT stage was sustained in a multivariable Cox regression model ( P < 0.05). An increasing baseline CONUT stage was associated with a longer duration of admission, a greater requirement for the use of non-invasive and invasive mechanical ventilation, and other clinical outcomes (all P < 0.05). The ROC of CONUT for mortality had an area under the curve (AUC) and 95% confidence interval of 0.711 (0.676–0746). Conclusion: The CONUT index upon admission is potentially a reliable and independent prognostic indicator of mortality and length of hospitalization in COVID-19 patients.

Poor Nutritional Status and Dynapenia Are Highly Prevalent in Post-Acute COVID-19

“…According to the CONUT score, moderate-severe malnutrition was detected in 21% of our patients, a prevalence lower than that previously observed in acute hospitalized patients (32,36). Interestingly, 33% of the patients were identified as malnourished by one of the two tools, but only 6% by both, suggesting a low agreement between MNA and CONUT.…”

“…Interestingly, 33% of the patients were identified as malnourished by one of the two tools, but only 6% by both, suggesting a low agreement between MNA and CONUT. Finally, the prevalence of malnutrition was related to the number of comorbidities only for MNA but not for CONUT (data not shown), in partial disagreement with previous studies (32,36). As for BC, while obesity and increased FM have frequently been associated with disease severity, length of hospital stay, ICU admission, and death (3,20,(37)(38)(39)(40)(41)(42)(43)(44), only a few studies have yielded data on muscle wasting, low FFM, and appendicular skeletal muscle in COVID-19 patients (4,7,8,14); for instance, a low pectoralis muscle area was found to be a predictor of poor prognosis (45).…”

“…The poor nutritional status in COVID-19 patients may be due to multiple factors such as inflammation, hypercatabolism, increased work of respiratory muscles, etc (2-4); so far, using different tools and criteria, the risk of malnutrition has been estimated between 39 and 86%, and the prevalence of malnutrition from 5 to 69% (2, 28). In the patients we studied, the nutritional assessment was performed with two different tools, MNA and CONUT, which have been already related to hospitalization, adverse outcomes, and mortality in COVID-19 disease (29)(30)(31)(32)(33)(34)(35)(36); For consistency within the sample, MNA was also applied in patients aged <60 years (27% of total). According to the long form of MNA, 62% of the patients were at risk of malnutrition and 18% were malnourished, in agreement with the data of Haray et al (29) in ICU COVID-19 patients, but not with those of Kananen et al (31), who used the MNA short form in elderly hospitalized COVID-19 patients.…”

Nutritional Risk Assessment Scores Effectively Predict Mortality in Critically Ill Patients with Severe COVID-19

“…Our cut-off of 7.5 was significantly higher, placing most of the patients exceeding this cut-off value in the severe malnutrition group. However, in a study including 1627 COVID-19 patients irrespective of disease severity, only 4.9% were classified as severely malnourished based on the CONUT score [ 35 ], compared to 25.5% among the patients with severe COVID-19 in our cohort. This might be explained by the fact that patients with a higher degree of nutritional imbalance are more prone to being admitted to the ICU, thus potentially skewing the cut-off towards higher values.…”

“…Like PNI, CONUT was validated in a wide range of clinical scenarios and was associated with many ICU-related outcomes, from incidence of delirium [ 31 ] to mortality in various conditions such as trauma, heart failure, or irrespective of ICU-admittance cause [ 32 , 33 , 34 ]. While to this point there have been no published articles on the relevance of nutritional evaluation using CONUT in COVID-19 patients hospitalized solely in the ICU, the available data suggests that patients with a higher CONUT score were prone to more severe outcomes, having a more extended hospital stay, required mechanical ventilation more frequently, and had higher in-hospital mortality [ 35 , 36 , 37 ]. In a study including patients across the entire COVID-19 disease severity spectrum, a CONUT score above 5.5 predicted mortality with an AUROC of 0.83, suggesting that even a mild-to-moderate nutritional imbalance might predispose patients to a worse disease trajectory [ 36 ].…”