European Journal of Cardiovascular Medicine

Critically ill patients are in severe catabolic stress and have pro-inflammatory status due to increased release of stress-related hormones and cytokines. The severity of their disease could affect the severity of catabolism and protein loss leading to malnutrition ^[1]. Nutritional therapy has been shown to improve clinical outcomes in critically ill patients who are at rhigh risk of malnutrition. To effectively identify those ICU patients who are at risk and most likely to benefit from nutritional support, validated assessment tools are essential. Traditional nutritional risk scores, however have not been specifically validated for use in ICU setting. In response to this gap, Heyland et al. developed the Nutritional risk in critically ill (NUTRIC) score-the first tool tailored for critically ill patients. This score is designed to identify patients who may benefit from targeted and aggressive protien-energy supplementation during their ICU stay, with goal of reducing mortality and shortening the duration of mechanical ventilation ^[2]. The NUTRIC score integrates both prehospital and ICU admission parameter to assess nutritional risk in critically ill patients. It includes indicators of acute starvation (such as duration of hospitalisation prior to ICU admission), acute inflammation, chronic inflammation and illness severity ^[3].

Nearly 42.5% of mechanically ventilated patients admitted to the ICU were at nutritional risk. Malnutrition negatively affects patients by decreasing quality of life, prolonging length of hospital stay, causing functional impairment, increased incidence of nosocomial infections, increased healthcare costs, higher hospital readmission rates and mortality ^[4]. Hence it is important to assess the nutritional status in critically patients using the best tools available and institute optimal nutrition to these patients.

Rahman et al. (2016) externally validated the mNUTRIC score in 1,199 mechanically ventilated patients with multi-organ dysfunction and confirmed its ability to predict both 28-day and 6-month mortality even without IL-6. Importantly, the score interacted with nutritional adequacy, as patients with higher scores (≥6) showed improved survival with greater protein-calorie intake, while those with lower scores did not. These findings highlight the mNUTRIC score as a practical bedside tool for identifying high-risk patients and guiding targeted nutrition therapy in the ICU. ^[5]

An Observational Cross-Sectional Study carried out in the Intensive Care Unit of Dr. D.Y. Patil Medical College, Hospital & Research Institute, Kolhapur for a duration of 18 months and was commenced after obtaining approval from the Institutional Ethics Committee. The primary objective was to evaluate nutritional risk, using the NUTRIC score and correlate it with clinical outcomes such as mortality, length of ICU stay, time to weaning from ventilation and number of days on mechanical venttilator. Eligible participants included all adult patients (aged ≥18 years) of either gender who were admitted to the ICU and initiated on mechanical ventilation. These patients were enrolled within the first 24 hours of intubation and mechanical ventilation based on pre-defined inclusion and exclusion criteria. Patients with burns, pre-existing neuromuscular disorders, advanced malignancy or AIDS, those readmitted to ICU, or whose duration of mechanical ventilation was more than 24 hours were excluded.

After obtaining informed consent from the patient’s legally authorized representative, detailed clinical data were collected using a structured case record form. The following data were recorded:  Demographic details, Comorbidities, Clinical indications for mechanical ventilation,  Hemodynamic parameters and laboratory results, Glasgow Coma Scale (GCS), APACHE II, and SOFA scores were calculated and the patients were followed up and the outcomes were note down. Serum IL-6 levels were measured using kits from Sunlong Biotech, by Sandwich ELISA method.

The NUTRIC score was calculated using age, APACHE II score, SOFA score, number of comorbidities, days from hospital to ICU admission, and serum IL-6 level. The total score ranges from 0–10, with a score of ≥6 indicating high nutritional risk and accordingly patients were categorised as high and low nutritional risk. Statistical analysis was performed to assess the correlation between nutritional risk (NUTRIC score) and patient outcomes.

Table 1: Mean Demographic and clinical characteristics.

Table 1 shows mean demographic and clinical characteristics. Participants were mostly older adults 59.5±16.09 years, ranging from 22 to 87 years. Mean IL-6 was 89.12±35.77 pg./ml , indicating significant systemic inflammation among the patients. APACHE II score (mean 26.46 ±8) and SOFA score (mean 9.46±3.96) suggest moderate to severe illness. NUTRIC score (mean 5.06±1.87) indicates a moderate risk of malnutrition in critically ill patients. Duration between hospital admission and intubation averaged around 2 days, implying early respiratory deterioration. ICU stay was around 15 days on average. Time to weaning from mechanical ventilation was about 8 days and average days on ventilator wasaround  9 days

Graph 1: Comorbidid conditions

Graph 1 depicts the distribution of comorbidities in the study population. Hypertension (46.9%) and neurological disease (43.8%) were the most frequent, followed by diabetes mellitus (29.4%). Coronary artery disease and chronic obstructive airway disease were each observed in 13.1% of patients, while chronic renal failure (6.9%) and dilated cardiomyopathy (1.3%) were less common.

Table 2: Correlation between Nutritional risk groups, Length of ICU stay, Days on ventilator, Time to weaning from mechanical ventilation, Mortality and IL-6

Table 2 shows the Nutritonal Risk Groups are negatively correlated with ICU stay (r = -0.223, p = 0.005), Days on ventilator (r = -0.193, p = 0.015), Time to weaning (r = -0.192, p = 0.015) and vice versa and positively correlated with mortality (r = 0.389, p = 0.000) and IL-6 (r = 0.319, p = 0.000) and vice versa suggesting higher nutritional risk is associated with higher mortality and higher IL-6 levels but shorter ICU stay, fewer ventilator days, likely due to early mortality.

IL-6 levels demonstrated a significant positive correlation with risk groups (r = 0.319, p < 0.001) and mortality (r = 0.212, p = 0.007), indicating that higher IL-6 values were associated with high risk categories and increased mortality. However, IL-6 showed no significant correlation with ICU stay, days on ventilator, or time to weaning from mechanical ventilation.

ICU Stay is strongly positively correlated with Days on ventilator (r = 0.975, p = 0.000), time to weaning (r = 0.972, p = 0.000) and vice versa and negatively correlated with Mortality (r = -0.692, p = 0.000) and vice versa. Days on Ventilator shows Strong positive correlation wDith Time to weaning (r = 0.999, p = 0.000), Negative correlation with Mortality (r = -0.597, p = 0.000), IL-6 (r = --.069, p = .394) and vice versa. Time to Weaning Shows Strong negative correlation with Mortality (r = -0.591, p = 0.000), IL-6 (r = --.068, p = .396) and vice versa.

Graph 2: Nutritional Risk among the survivors and non survivor; Graph 3: Nutritional Score groups among the survivors and non survivors

Graphs 2 and 3 demonstrate the association between nutritional risk and outcomes. Among survivors, 88.6% had low NUTRIC scores (0–5) and only 11.4% had high scores (6–10), whereas 57.6–58.4% of non-survivors had high nutritional risk. This difference was statistically significant (p = 0.001), indicating that higher nutritional risk strongly correlated with mortality.

Graph 4: System involved among the Nutritional risk groups

Graph 5: IL-6 groups with respect to different system involved

Graphs 4 and 5 compare nutritional risk and IL-6 levels across different systems. Nearly half of patients with respiratory disease (47.1%) were at high nutritional risk, while sepsis, renal, and pancreatic involvement showed 100% high risk. Overall, sepsis demonstrated the strongest association with nutritional deterioration (71.1% high risk; p = 0.001). IL-6 levels also varied by system, with most nervous system (98%) and respiratory patients (94.1%) having IL-6 ≤100 pg/mL, whereas sepsis showed a wider distribution (76.3% ≤100, 18.4% 100–200, 6.2% >200). Hepatobiliary and renal patients also exhibited relatively higher IL-6 levels compared to other groups. This association between IL-6 distribution and system involvement was statistically significant (p = 0.042).

Graph 6: Association of Acute Renal Failure with IL 6 groups

Graph 6 shows the association of Acute Renal Failure with IL 6 groups. Among those with acute renal failure.75.7% had IL-6 levels 0–100, 17.6% had 100–200, 6.8% had IL-6 >200. Among those without acute renal failure. 96.5% had IL-6 levels between 0–100, and none had IL-6 levels >200. P value is 0.001, indicating the difference is statistically significant.

Critically ill patients requiring invasive mechanical ventilation represent one of the sickest subgroups in the ICU, with disproportionately high morbidity and mortality. In our cohort, the mean age closely paralleled findings from South Asia. Kalaiselvan et al. reported a mean age of 55 years in 678 ventilated patients in India ^[2], while Ata ur-Rehman et al. described a similar mean of 55.8 years in Pakistan ^[6]. This similarity underscores that critical illness requiring prolonged respiratory support in this region predominantly affects middle-aged and older adults, in whom the cumulative burden of comorbidities such as diabetes, hypertension, and cardiovascular disease contributes to vulnerability. Illness severity was high, reflected by mean APACHE II and SOFA scores of 26.46 ±8 and 9.46±3.96, respectively. These values indicate moderate-to-severe physiologic compromise and are consistent with international reports. Moretti et al. documented a mean APACHE II of 20.7 among ventilated patients ^[7].

Nutritional risk, a key determinant of ICU outcomes, was high in this cohort. The mean NUTRIC score was 5.06 ± 1.87, indicating that a large proportion of patients were nutritionally vulnerable. Comparable results have been reported regionally and globally. Kalaiselvan et al. observed that 42.5% of ventilated ICU patients had scores ≥5 ^[2], while Ata ur-Rehman et al. reported 45% with elevated mNUTRIC scores, which correlated with longer ICU stays and increased mortality ^[6]. Dadarwal et al. found an even higher prevalence, with 69% of ventilated patients classified as high risk, who subsequently experienced fewer ventilator-free days and prolonged ICU admissions ^[8]. Taken together, these findings emphasize that malnutrition is common among ventilated patients and significantly worsens outcomes. Importantly, the NUTRIC score serves not only as a risk stratification tool but also as a practical guide for initiating early nutritional interventions aimed at mitigating catabolism, preserving lean body mass, and potentially improving survival.

Respiratory outcomes in this study further reflected the interplay between nutrition and critical illness. The mean duration of ventilation was 8.91 days, and the mean time to weaning was 8.0 days. These findings are consistent with Moretti et al., who reported an average ventilator duration of 8.55 days among survivors ^[7]. Sutrisnawati et al. similarly demonstrated that higher NUTRIC scores independently predicted prolonged ventilator dependence ^[9]. Malnutrition impairs respiratory muscle function, delays tissue repair, and increases susceptibility to infection, thereby prolonging ventilator need and complicating weaning. Thus, nutritional optimization is not merely supportive care but an essential element of ventilatory management.

The average ICU stay in our cohort was 15.45 days, considerably longer than that reported in lower-risk groups. Dadarwal et al. observed that high-risk patients stayed an average of 11.75 days, compared with only 6.46 days in low-risk patients ^[8]. While differences in population and ICU practices may account for the absolute durations, the trend is consistent across studies: higher nutritional risk is associated with prolonged ICU admissions and increased healthcare resource utilization. In resource-constrained settings, this has important implications for planning, triage, and optimizing use of critical care beds.

Inflammation, another hallmark of critical illness, was evident in this study, with a mean IL-6 concentration of 89.12± 35.77 pg/mL. IL-6, part of the original NUTRIC score, is a sensitive biomarker of catabolic stress, immune dysregulation, and mortality, although its routine measurement is often limited in many ICUs. Moretti et al. showed that CRP may be an acceptable surrogate, but IL-6 remains superior in sensitivity and specificity ^[7]. Our analysis revealed important system-specific IL-6 patterns. Sepsis demonstrated the widest spread of values, with nearly a quarter of patients above 100 pg/mL, reflecting the systemic inflammatory response. Hepatobiliary conditions also exhibited elevated IL-6, supporting the link between liver dysfunction and exaggerated cytokine release. Renal involvement was associated with the highest values, with nearly two-thirds of patients falling between 100 and 200 pg/mL. Ata ur-Rehman et al. and Khan et al. have both confirmed that acute kidney injury is linked with heightened inflammation, increased nutritional risk, and poor outcomes ^[6,10]. In contrast, neurological and respiratory system patients typically had lower IL-6 values unless complicated by multi-organ dysfunction. These findings reaffirm the pathophysiologic role of IL-6 as a marker integrating organ failure, nutrition, and prognosis.

A male predominance was observed in our study, consistent with regional and global literature. Kalaiselvan et al. reported 67% male ventilated patients in India ^[2], Ata ur-Rehman et al. found 53% in Pakistan ^[6], Khan et al. documented 75.2% in a multicenter study ^[10], and Dadarwal et al. reported 63% ^[8]. Several factors likely contribute to this pattern. Men are more frequently affected by cardiovascular disease, chronic respiratory disorders, and hypertension, and occupational or environmental exposures may further increase their risk. Additionally, sociocultural influences on health-seeking behavior and healthcare access may lead to higher ICU representation among men in South Asia.

Comorbidity burden strongly influenced nutritional risk and outcomes. Patients with hypertension, diabetes, renal disease, chronic lung disease, and neurological disorders were more likely to score ≥5 on the NUTRIC scale. Khan et al. demonstrated that comorbidity count was directly associated with higher nutritional risk and poor ICU outcomes ^[10]. Kalaiselvan et al. found that patients with diabetes and cardiovascular disease were frequently classified as high risk and had higher mortality ^[2], while Ata ur-Rehman et al. similarly observed that diabetic and chronically ill patients had elevated mNUTRIC scores, longer ICU admissions, and greater mortality ^[6]. Dadarwal et al. emphasized the impact of neurological and pulmonary comorbidities, including COPD, on elevated nutritional risk and reduced ventilator-free days ^[8]. Collectively, these data highlight comorbidity burden as a key driver of nutritional vulnerability and adverse prognosis.

Correlation analyses in our study offered further insights. High nutritional risk demonstrated strong positive correlations with mortality (r = 0.389, p < 0.001) and IL-6 levels (r = 0.319, p < 0.001), confirming that malnutrition and inflammation together drive poor outcomes. Unexpectedly, high-risk patients demonstrated negative correlations with ICU stay, ventilator days, and time to weaning. This paradox is explained by early mortality: patients at high risk deteriorate rapidly and die before prolonged support is possible, thus shortening their measured ICU course. Similar trends have been noted by Kalaiselvan et al. and Khan et al. ^[2,10]. ICU stay correlated strongly with ventilator days (r = 0.975, p < 0.001) and time to weaning (r = 0.972, p < 0.001), confirming the interdependence of these measures. Mortality correlated positively with IL-6 (r = 0.212, p = 0.007), further reaffirming inflammation as a central predictor of outcome. Survivors generally required longer ICU care and ventilatory support but eventually achieved successful weaning, while non-survivors experienced rapid decline and early death.

Taken together, these findings validate the NUTRIC score as a robust prognostic tool in mechanically ventilated patients. Elevated scores consistently predicted higher mortality, fewer ventilator-free days, and prolonged ICU stays. IL-6 provided additional prognostic insight, especially in sepsis, hepatobiliary, and renal disease, where inflammatory burden was greatest. From a clinical perspective, the early identification of high-risk patients allows for timely nutritional support, targeted monitoring, and appropriate allocation of ICU resources. In resource-limited environments, such objective risk stratification tools are invaluable. Furthermore, the observed link between comorbidities and nutritional risk underscores the importance of aggressive chronic disease management in the community to reduce the burden of critical illness.

This study demonstrates the critical role of nutritional risk assessment using the NUTRIC score in predicting outcomes among mechanically ventilated ICU patients. A significant proportion of non-survivors had high NUTRIC scores, confirming its strong association with mortality. Additionally, high nutritional risk was linked with elevated IL-6 levels, sepsis, acute renal failure, and longer ICU stays, all of which highlight the interplay between inflammation, organ dysfunction, and malnutrition. In conclusion, the NUTRIC score is a simple yet powerful prognostic tool that should be utilized alongside clinical severity scores to guide individualized patient care and nutritional strategies in critical care setting

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