Impact of nutritional status on the outcome of critically ill pediatric patients

Abstract

BACKGROUND

Malnutrition among patients admitted to a pediatric intensive care unit (PICU) is common. However, there is a lack of data on its impact on the critically ill.

AIM

To assess the impact of nutritional status on the outcome of critically ill children admitted to PICU.

METHODS

This observational study was conducted in a tertiary care teaching institute for one year, including 210 children aged 1 month to 14 years admitted to a 15-bed PICU for a minimum of 24 hours. Patients with less than 24 hours of PICU stay, who received palliative care, or with syndromic short stature were excluded. Relevant data were collected including anthropometric details, demographic data, duration of mechanical ventilation (MV), PICU, and hospital stay and outcome. Malnourished and well-nourished groups were compared using an independent t-test, one-way analysis of variance, and χ² test.

RESULTS

Among 210 patients, there were 129 males and 81 females. There were 57 (27.1%) children less than 6 months of age, 95 (45.2%) between 6 months and 5 years, and 58 (27.6%) more than 5 years of age. The prevalence of malnutrition in the study sample was 51.9% (n = 109). The overall mortality was 22.9% (48/210), 26.6% (29/109) among malnourished, and 18.8% (19/101) among well-nourished children (P = 0.241). A significant association was found between the severity of malnutrition and duration of MV (P = 0.001), PICU stay (P = 0.001), and hospital stay (P = 0.021).

CONCLUSION

Malnutrition is common in critically ill children and contributes to poor clinical outcomes such as duration of MV, PICU, and hospital stay. However, mortality was comparable in both groups.

Key Words: Well-nourished; Malnourished; Pediatric intensive care unit; Mortality; Critically ill; Child

Core Tip: Malnutrition is prevalent among critically ill children admitted to pediatric intensive care unit (PICU). This study aimed to assess the impact of malnutrition on patient outcomes. Researchers analyzed data from 210 children aged 1 month to 14 years and malnutrition was identified in 51.9% of patients. While mortality rates were similar between malnourished and well-nourished groups, the former experienced significantly longer durations of mechanical ventilation, PICU stay, and overall hospital stay. These findings highlight the importance of early nutritional assessment and intervention in critically ill children to improve clinical outcomes.

INTRODUCTION

Malnutrition is a common finding in critically ill children admitted to the pediatric intensive care unit (PICU) but is often under-reported or neglected, which may adversely affect the clinical outcome in such patients as these children are at increased risk of infection/sepsis, and have impaired immunity, wound healing, and gut integrity[1]. The exact prevalence of malnutrition in critically ill children is not documented. However, about 20% to 25% of the children admitted to PICU are reported to be malnourished at the time of admission, and their nutritional status may be further compromised during their stay in PICU[2].

The physical growth is rapid in young children and thus the growth faltering among them is also rapid. Malnutrition in critically ill children has been attributed to both the disease itself as well as to health-care-related factors. Low intake of protein and calories, pre-existing comorbid conditions, and malabsorption are some of the causes of malnutrition in critically ill children. The nutritional requirements of children depend upon several factors such as energy expenditure at rest, severity of disease, type of disease, metabolism of macronutrients, etc. The discrepancy between the requirement and delivery of nutrients to the child is mainly due to difficulties in nutritional assessment.

Previous studies examining the association between malnutrition and clinical outcomes in PICUs have yielded conflicting results, with limited prospective data available. This body of research is particularly scarce in the Indian context[3,4]. Therefore, this study investigated this relationship in a tertiary care institute in Madhya Pradesh, India, where malnutrition is prevalent. As malnutrition is common in India, the nutritional status may be compromised further during critical illness and hospital stay. The objective of this study was to compare outcomes, including mortality, duration of mechanical ventilation (MV), length of PICU, and hospital stay in malnourished and non-malnourished children.

MATERIALS AND METHODS

This prospective observational study was done in a tertiary care teaching institute in Central India from January 2022 to December 2022. Prior approval from the institutional ethical committee was obtained (IEC Protocol No. 106/IEC/2021). The study included 210 children aged 1 month to 14 years admitted to PICU for a minimum stay of 24 hours. Patients with PICU stay of less than 24 hours, who received palliative care at the end of life, or children with syndromic short stature were excluded.

The required sample size for well-nourished and malnourished groups to achieve 80% power and a 95%CI, was calculated using the standard formula for comparing two proportions: N = (Zα/2 + Zβ)² × [p1 (1-p1) + p2 (1-p2)]/(p1-p2)². The estimated sample size was 190. Informed consent from parents/legal guardians was obtained before recruiting the patients. The children were stabilized as per standard management protocols. The severity of the illness was assessed using the pediatric risk mortality score (PRISM) 3 score[5]. Anthropometric variables were assessed for all the cases including weight, length, mid-upper arm circumference (MUAC), and Weight for length (for children up to 5 years of age)/body mass index (BMI) (for children aged 5 years or more) on the day of admission. Weight was measured using an electronic digital scale to the nearest 0.1 kg. Length was taken in a lying down position owing to the critical nature of the illness using a non-stretchable measuring tape. The child’s head was held facing perpendicular to the horizontal plane, knees and ankles extended, and toes pointing upwards. The measurement was recorded to the nearest 0.1 cm. MUAC was measured to the nearest 0.1 cm, using a flexible non-stretchable tape laid at the midpoint between the acromion and olecranon processes using the cross-tape method. Children were classified as non-malnourished, moderately malnourished, and severely malnourished defined as BMI for age or weight for height (for children less than 5 years of age) for 0 to −2 SD, −2 to −3 SD, and less than −3 SD of World Health Organization growth charts[6]. For children aged 6 months to 5 years, in addition to the above criteria, MUAC 11.5 cm-12.5 cm was taken as moderately malnourished, and MUAC < 11.5 cm was taken as severely malnourished[7]. Post-admission, anthropometric measurements were collected on days 3, 7, and weekly, while vital signs, inotrope score, and PRISM score were monitored continuously until discharge. Due to variable patient stay durations, data analysis for these parameters could not be done.

Data was compiled with the help of Excel and analysis was done using IBM SPSS software version 20. Categorical and continuous variables were expressed as frequency (proportions) and mean (standard deviation), respectively. Study groups were compared using an independent t-test, one-way analysis of variance (ANOVA), and χ² test. A multivariate logistic regression analysis was used to analyze the impact of factors like PRISM score, malnutrition, age, gender, and shock on mortality and other outcome variables. In this analysis, prolonged PICU stay was defined as exceeding 5 days, prolonged hospital stay exceeding 10 days, and prolonged MV exceeding 3 days. A P-value of less than 0.05 was considered statistically significant.

RESULTS

Among 210 patients enrolled, 129 (61.4%) were males and 81 (38.6%) were females. There were 57 (27.1%) children less than 6 months of age, 95 (45.2%) between 6 months and 5 years, and 58 (27.6%) more than 5 years of age. There were 101/210 (48.09%) well-nourished, 42/210 (20%) moderately malnourished, and 67/210 (31.9%) severely undernourished children. Malnutrition was found in 109 (51.9%) children. The most common system involved was the respiratory system (35.7%), followed by the central nervous system, (31.9%) and the gastrointestinal tract (12.9%). Cardiovascular and renal systems were involved in 8.1% and 5.7% of cases, respectively. A total of 48 children expired (22.9%); mortality amongst malnourished was 26.6% (29) and amongst well-nourished was 18.8% (19) (P = 0.241) as shown in Table 1.

Table 1 Outcome variables according to severity of malnutrition, n (%)/mean ± SD.

Outcome variables	Severely malnourished (n = 67)	Moderately malnourished (n = 42)	Well-nourished (n = 101)	P value
Mortality	20 (29.9)	9 (21.4)	19 (18.8)	0.241
MV duration (Days)	1.87 ± 0.7	1.74 ± 0.5	1.3 ± 0.8	0.001
Hospital stay (Days)	9.64 ± 5	9.3 ± 3.2	8.1 ± 3.1	0.021
PICU stay (Days)	5.66 ± 2.5	4.6 ± 2.1	4.2 ± 2.1	0.001
PRISM score	11.28 ± 5.5	8.93 ± 3.8	9.15 ± 4.2	0.147
Inotrope score at admission	10.9 ± 3.6	9.4 ± 4.1	10.09 ± 4.0	0.949

MV: Mechanical ventilation; PICU: Pediatric intensive care unit; PRISM: Pediatric risk mortality score.

On applying ANOVA, the duration of MV, hospital, and PICU stay increased gradually with the increasing severity of malnutrition and were significantly higher among severely malnourished patients than moderately and well-nourished patients (P < 0.05) as shown in Table 1. The same table also shows that there was no significant difference in PRISM score and inotrope score at admission between malnourished and well-nourished children.

After adjusting for potential confounders like age, gender, PRISM score, and inotrope score at admission, the multivariate logistic regression analysis revealed that malnutrition was independently associated with a significantly increased risk of prolonged PICU and hospital stay and longer duration of MV as shown in Table 2. However, mortality risk was not increased in these patients compared to the well-nourished patients.

Table 2 Multivariate logistic regression analysis to assess the relationship between malnutrition and outcome variables.

Outcome	SAM	P value	MAM	P value
	Adjusted OR (95%CI)1		Adjusted OR (95%CI)1
Mortality	1.21 (0.68-2.16)	0.521	1.14 (0.55-2.36)	0.720
Prolonged PICU stay2	2.87 (1.63-5.04)	< 0.001	1.75 (1.02-3.01)	0.042
Prolonged hospital stay2	2.41 (1.38-4.21)	0.002	1.62 (0.96-2.74)	0.070
Prolonged ventilation3	3.25 (1.82-5.79)	< 0.001	1.96 (1.13-3.39)	0.016

¹Adjusted for age, gender, pediatric risk mortality score, and inotrope score at admission.

²Prolonged pediatric intensive care unit stay: > 5 days.

²Prolonged hospital stay: > 10 days.

³Prolonged mechanical ventilation: > 3 days.

OR: Odds ratio; SAM: Severe acute malnutrition; MAM: Moderate acute malnutrition; PICU: Pediatric intensive care unit.

DISCUSSION

The present study was conducted on 210 critically ill children to assess the impact of nutritional status on the outcome of these children. Malnutrition was reported in 109 (51.9%) cases and the overall mortality was 22.9%. There was no significant difference in mortality between malnourished and well-nourished children (P = 0.241); however, the length of MV (P = 0.001), PICU stay (P = 0.001), and hospital stay (P = 0.021) was significantly higher in malnourished children.

Despite the massive burden of malnutrition in developing nations, there is scanty data regarding its impact on critically ill pediatric patients. We found no significant association of malnutrition with the outcome (P > 0.05). Our findings are similar to those reported by de Souza Menezes et al[8] who found no significant association of malnutrition with mortality. Bagri et al[4] observed mortality in 38.8% of the children admitted to PICU and no significant association of mortality with the nutritional status of critically ill children like our study.

Malnourished children required a significantly longer duration of MV than the well-nourished children (1.8 ± 0.5 vs 1.3 ± 0.8 days; P < 0.0001). Bagri et al[4] also reported the significantly prolonged duration of MV in severely malnourished cases (> 7 days) (P < 0.05)[4]. de Souza Menezes et al[8] documented a higher MV duration in malnourished children on univariate and multivariate analysis (6.30 ± 3.18 vs 5.14 ± 3.43 days; P = 0.003)[8]. Grippa et al[9] also reported a significant difference in MV duration between malnourished and adequately nourished patients as per the Kaplan-Meier survival curves. Bechard et al[10] found that underweight was associated with 1.3 (P = 0.001) fewer ventilator-free days than normal-weight children. In a study by Nangalu et al[11], underweight children needed prolonged MV (P = 0.0063) as compared to children with normal nutrition.

The length of PICU stay (5.3 ± 2.5 vs 4.2 ± 2.1 days), and hospital stay (9.5 ± 3.5 vs 8.1 ± 3.1 days) was documented to be significantly higher in malnourished children as compared to well-nourished children. De Souza Menezes et al[8] reported a significant association of length of PICU stay > 5 days with malnutrition (93/175 malnourished vs 90/210 well-nourished patients (P < 0.05)[8]. Valla et al[12] documented a prolonged PICU stay in children experiencing faltering growth. Chaitra et al[3] reported higher odds of prolonged hospital and PICU stay in overweight/ obese and underweight children, though the difference was statistically insignificant (P > 0.05). A study by Nangalu et al[11] found that underweight children had a longer hospital stay (P = 0.0332) than children with normal nutrition.

Recently in a meta-analysis analyzing data from 17 observational studies with 10638 patients, Albadi et al[13] reported a slightly higher risk of mortality [risk difference (RD) = 0.02, P = 0.05] in undernourished than in well-nourished children. However, this finding contrasts with the findings of our research which may be due to the small sample size and different nutritional assessment methods adopted in various studies. They reported a longer PICU stay (RD = 0.07, P = 0.007) and duration of MV (RD = 0.13, P < 0.0001) in under-nourished children which aligns with our findings[13]. In another meta-analysis analyzing 21558 patients from 20 studies, Toh et al[14] found that children’s weight (BMI) upon entering the PICU may not be a good predictor of the outcomes including mortality, duration of MV, PICU, and hospital stay. However, the authors found higher mortality odds in underweight and overweight/obese patients when they focused on studies of mixed patient cohorts which is the most common setup for PICUs worldwide including ours[14].

Nutritional status at PICU admission can be an important predictor of morbidity and mortality. Poorer clinical outcomes in malnourished children can be attributed to their impaired humoral and cell-mediated immunity, due to reductive adaptation, and micronutrient deficiencies. Malnutrition in critically ill children can significantly impact clinical outcomes through a complex interplay of physiological and metabolic factors. Reduced nutrient intake leads to impaired protein synthesis, hindering tissue repair and immune function. This weakens the body's ability to fight infections, prolonging hospital stays and increasing the risk of complications. Moreover, malnutrition can disrupt the delicate balance of hormones, leading to increased inflammation and oxidative stress. This chronic inflammatory state further weakens organ function, delays recovery, and increases the risk of complications such as sepsis and organ dysfunction, ultimately contributing to prolonged ICU stays and potentially increased mortality.

Our study had certain limitations. A small sample size limited the study; however, a post hoc power analysis revealed that the study had sufficient power to detect large differences between the groups. This was a single-center study, so results cannot be extrapolated to larger populations. The Patients were monitored only till discharge; long-term follow-up of these children might have helped in assessing the effect of nutritional status on long-term outcomes such as physical growth and neurodevelopment. Malnourishment was defined based on anthropometry only, and other factors like albumin, muscle mass thickness, and calorie and protein deficit were not considered.

CONCLUSION

Undernutrition is common in children admitted to PICU and it was associated with a longer duration of PICU and hospital stay, as well as the prolonged need for MV. However, the association between malnutrition and mortality was not significant. Nutritional status assessment should be considered an important component in the care and management of critically ill children. Comprehensive care including nutrition interventions should be provided to improve their health outcomes.