Nutritional Status and Mortality in the Critically Ill

Characteristics and Outcomes of Adult Inpatients With Malnutrition

BACKGROUND

The diagnosis of malnutrition remains controversial. Furthermore, it is unknown if physician diagnosis of malnutrition impacts outcomes. We sought to compare outcomes of patients with physician diagnosed malnutrition to patients recognized as malnourished by registered dietitians (RDs), but not physicians, and to describe the impact of each of 6 criteria on the diagnosis of malnutrition.

METHODS

We conducted a retrospective cohort study of adult patients identified as meeting criteria for malnutrition. Pediatric, psychiatric, maternity, and rehabilitation patients were excluded. Patient demographics, clinical data, malnutrition type and criteria, nutrition interventions, and outcomes were abstracted from the electronic medical record.

RESULTS

RDs identified malnutrition for 291 admissions during our study period. This represents 4.1% of hospital discharges. Physicians only diagnosed malnutrition on 93 (32%) of these cases. Physicians diagnosed malnutrition in 43% of patients with a body mass index <18.5 but only 26% of patients with body mass index higher than 18.5. Patients with a physician diagnosis had a longer length of stay (mean 14.9 days vs 7.1 days) and were more likely to receive parenteral nutrition (PN) (20.4% vs 4.6%). Of the patients, 62% had malnutrition due to chronic illness. Of the 6 criteria used to identify malnourished patients, weight loss and reduced energy intake were the most common.

CONCLUSIONS

Malnutrition is underrecognized by physicians. However, further research is needed to determine if physician recognition and treatment of malnutrition can improve outcomes. The most important criteria for identifying malnourished patients in our cohort were weight loss and reduced energy intake.

Phase angle is related to outcome after ICU admission; an observational study

INTRODUCTION

Malnutrition at the time of ICU admission is associated with an increased morbidity and mortality. Malnutrition is most often assessed by a questionnaire but can also be determined with bio-impedance and measurement of phase angle. In a single-centre observational study we compared the percentage of malnutrition in patients admitted to our ICU, according to the Short Nutritional Assessment Questionnaire (SNAQ) with the phase angle measured with bio-impedance. Furthermore, we questioned whether malnutrition is related to outcome parameters.

METHODS

In a 15 week period consecutive patients admitted to the ICU were included. Exclusion criteria included age <18 years, anatomical and/or neurological abnormalities of the limbs and an ICU stay less than 6 h. Bio-impedance measurements were performed shortly after admission, the SNAQ was obtained from the patient or legal representative. Malnutrition is considered with a SNAQ ≥2 or a phase angle of <5° for men and <4.6° for women. The study was approved by our local ethical committee (MCL, nWMO 77, April 18, 2015).

RESULTS

299 Patients were included (66% male, age 66 ± 12 year, BMI 27 ± 4 kg/m² and APACHE II score 14 [11-17]), of which 64% elective and 36% acute admissions. Hospital mortality was 7.4%. Malnutrition was present in 16% according to the SNAQ and in 36% according to phase angle. There was a fair accordance between the SNAQ and phase angle. Phase angle was significantly higher in patients with a SNAQ score of 0-1 (5.5°±1.3) in comparison with patients with a SNAQ score ≥2 (4.4°± 1.1) (p < 0.001). Logistic regression analysis showed a significant relation between SNAQ and BMI, malignant disease and hospital length of stay and between phase angle and age, sex, BMI, malignant disease, hospital length of stay and hospital mortality.

CONCLUSION

Malnutrition was present in 16% according to the SNAQ and in 36% according to phase angle in our IC population. Malnutrition was associated with prolonged hospital length of stay. In this small population of mixed ICU patients, a low phase angle was found to independently predict hospital mortality. CLINICAL TRIALS.

GOV NUMBER

NCT02911181.

Malnutrition, Critical Illness Survivors, and Postdischarge Outcomes: A Cohort Study

BACKGROUND

We hypothesized that preexisting malnutrition in patients who survived critical care would be associated with adverse outcomes following hospital discharge.

METHODS

We performed an observational cohort study in 1 academic medical center in Boston. We studied 23,575 patients, aged ≥18 years, who received critical care between 2004 and 2011 and survived hospitalization.

RESULTS

The exposure of interest was malnutrition determined at intensive care unit (ICU) admission by a registered dietitian using clinical judgment and on data related to unintentional weight loss, inadequate nutrient intake, and wasting of muscle mass and/or subcutaneous fat. The primary outcome was 90-day postdischarge mortality. Secondary outcome was unplanned 30-day hospital readmission. Adjusted odds ratios were estimated by logistic regression models adjusted for age, race, sex, Deyo-Charlson Index, surgical ICU, sepsis, and acute organ failure. In the cohort, the absolute risk of 90-day postdischarge mortality was 5.9%, 11.7%, 15.8%, and 21.9% in patients without malnutrition, those at risk of malnutrition, nonspecific malnutrition, and protein-energy malnutrition, respectively. The odds of 90-day postdischarge mortality in patients at risk of malnutrition, nonspecific malnutrition, and protein-energy malnutrition fully adjusted were 1.77 (95% confidence interval [CI], 1.23-2.54), 2.51 (95% CI, 1.36-4.62), and 3.72 (95% CI, 2.16-6.39), respectively, relative to patients without malnutrition. Furthermore, the presence of malnutrition is a significant predictor of the odds of unplanned 30-day hospital readmission.

CONCLUSIONS

In patients treated with critical care who survive hospitalization, preexisting malnutrition is a robust predictor of subsequent mortality and unplanned hospital readmission.

The Obesity Paradox Is Not Observed in Critically Ill Patients on Early Enteral Nutrition

OBJECTIVES

To investigate the association between body mass index and mortality in a large, ICU population and determine if the relationship is observed among a subgroup of patients ordered early enteral nutrition.

DESIGN

Retrospective cohort study within a national clinical mixed ICU database of patients admitted between January 1, 2008, and June 30, 2015.

SETTING

Initial ICU admissions among patients monitored by tele-ICU programs and recorded in the Philips eICU Research Institute database.

PATIENTS

A total of 1,042,710 adult patient stays with ICU length of stay more than 24 hours, of which 74,771 were ordered enteral nutrition within the first 48 hours.

INTERVENTION

None.

MEASUREMENTS AND MAIN RESULTS

Patient stays from 409 ICUs were included. The average age, Acute Physiology and Chronic Health Evaluation IV score, and hospital mortality were 63.6 years, 56.7, and 9.0%, respectively. Hospital mortality among body mass index categories was estimated by multivariable modified Poisson regression models. Compared with the body mass index category 25.0-29.9 kg/m, hospital mortality was higher among underweight (body mass index, < 18.5; relative risk, 1.35; 95% CI, 1.32-1.39), normal weight (body mass index, 18.5-24.9; relative risk, 1.10; 95% CI, 1.09-1.12), and the extremely obese (body mass index, ≥ 50.0; relative risk, 1.10; 95% CI, 1.05-1.15). However, the risk was not statistically different from patients with body mass index 30.0-49.9 kg/m. Among patients ordered early enteral nutrition, the risk of mortality in the body mass index category 25.0-29.9 kg/m was not statistically different from those in the normal weight or extremely obese groups.

CONCLUSIONS

A survival advantage for overweight and obese patients was observed in this large cohort of critically ill patients. However, among those ordered early enteral nutrition, the survival disadvantage for body mass index categories less than 25.0 kg/m was minimal or unobservable when compared with higher body mass index categories.

Prognostic Importance of Low Admission Serum Creatinine Concentration for Mortality in Hospitalized Patients

OBJECTIVE

The study objective was to assess the association between low serum creatinine value at admission and in-hospital mortality in hospitalized patients.

METHODS

This was a retrospective single-center cohort study conducted at a tertiary referral hospital. All hospitalized adult patients between 2011 and 2013 who had an admission creatinine value available were identified for inclusion in this study. Admission creatinine value was categorized into 7 groups: ≤0.4, 0.5 to 0.6, 0.7 to 0.8, 0.9 to 1.0, 1.1 to 1.2, 1.3 to 1.4, and ≥1.5 mg/dL. The primary outcome was in-hospital mortality. Logistic regression analysis was performed to obtain the odds ratio of in-hospital mortality for the various admission creatinine levels, using a creatinine value of 0.7 to 0.8 mg/dL as the reference group in the analysis of all patients and female patients and of 0.9 to 1.0 mg/dL in the analysis of male patients because it was associated with the lowest in-hospital mortality.

RESULTS

Of 73,994 included patients, 973 (1.3%) died in the hospital. The association between different categories of admission creatinine value and in-hospital mortality assumed a U-shaped distribution, with both low and high creatinine values associated with higher in-hospital mortality. After adjustment for age, sex, ethnicity, principal diagnosis, and comorbid conditions, very low creatinine value (≤0.4 mg/dL) was significantly associated with increased mortality (odds ratio, 3.29; 95% confidence interval, 2.08-5.00), exceeding the risk related to a markedly increased creatinine value of ≥1.5 mg/dL (odds ratio, 2.56; 95% confidence interval, 2.07-3.17). The association remained significant in the subgroup analysis of male and female patients.

CONCLUSIONS

Low creatinine value at admission is independently associated with increased in-hospital mortality in hospitalized patients.

The differential diagnosis for failure to wean from mechanical ventilation

PURPOSE OF REVIEW

In this review, we discuss the causes for a failed weaning trial and specific diagnostic tests that could be conducted to identify the cause for weaning failure. We briefly highlight treatment strategies that may enhance the chance of weaning success.

RECENT FINDINGS

Impaired respiratory mechanics, respiratory muscle dysfunction, cardiac dysfunction, cognitive dysfunction, and metabolic disorders are recognized causes for weaning failure. In addition, iatrogenic factors may be at play. Most studies have focused on respiratory muscle dysfunction and cardiac dysfunction. Recent studies demonstrate that both ultrasound and electromyography are valuable tools to evaluate respiratory muscle function in ventilated patients. Sophisticated ultrasound techniques and biomarkers such as B-type natriuretic peptide, are valuable tools to identify cardiac dysfunction as a cause for weaning failure. Once a cause for weaning failure has been identified specific treatment should be instituted. Concerning treatment, both strength training and endurance training should be considered for patients with respiratory muscle weakness. Inotropes and vasodilators should be considered in case of heart failure.

SUMMARY

Understanding the complex pathophysiology of weaning failure in combination with a systematic diagnostic approach allows identification of the primary cause of weaning failure. This will help the clinician to choose a specific treatment strategy and therefore may fasten liberation from mechanical ventilation.

Functional Status in ICU Survivors and Out of Hospital Outcomes: A Cohort Study

OBJECTIVES

Functional status at hospital discharge may be a risk factor for adverse events among survivors of critical illness. We sought to examine the association between functional status at hospital discharge in survivors of critical care and risk of 90-day all-cause mortality after hospital discharge.

DESIGN

Single-center retrospective cohort study.

SETTING

Academic Medical Center.

PATIENTS

Ten thousand three hundred forty-three adults who received critical care from 1997 to 2011 and survived hospitalization.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The exposure of interest was functional status determined at hospital discharge by a licensed physical therapist and rated based on qualitative categories adapted from the Functional Independence Measure. The main outcome was 90-day post hospital discharge all-cause mortality. A categorical risk-prediction score was derived and validated based on a logistic regression model of the function grades for each assessment. In an adjusted logistic regression model, the lowest quartile of functional status at hospital discharge was associated with an increased odds of 90-day postdischarge mortality compared with patients with independent functional status (odds ratio, 7.63 [95% CI, 3.83-15.22; p < 0.001]). In patients who had at least 7 days of physical therapy treatment prior to hospital discharge (n = 2,293), the adjusted odds of 90-day postdischarge mortality in patients with marked improvement in functional status at discharge was 64% less than patients with no change in functional status (odds ratio, 0.36 [95% CI, 0.24-0.53]; p < 0.001).

CONCLUSIONS

Lower functional status at hospital discharge in survivors of critical illness is associated with increased postdischarge mortality. Furthermore, patients whose functional status improves before discharge have decreased odds of postdischarge mortality.

Metabolites Associated With Malnutrition in the Intensive Care Unit Are Also Associated With 28-Day Mortality

BACKGROUND

We hypothesized that metabolic profiles would differ in critically ill patients with malnutrition relative to those without.

MATERIALS AND METHODS

We performed a prospective cohort study on 85 adult patients with systemic inflammatory response syndrome or sepsis admitted to a 20-bed medical intensive care unit (ICU) in Boston. We generated metabolomic profiles using gas and liquid chromatography and mass spectroscopy. We followed this by logistic regression and partial least squares discriminant analysis to identify individual metabolites that were significant. We then interrogated the entire metabolomics profile using metabolite set enrichment analysis and network model construction of chemical-protein target interactions to identify groups of metabolites and pathways that were differentiates in patients with and without malnutrition.

RESULTS

Of the cohort, 38% were malnourished at admission to the ICU. Metabolomic profiles differed in critically ill patients with malnutrition relative to those without. Ten metabolites were significantly associated with malnutrition ( P < .05). A parsimonious model of 5 metabolites effectively differentiated patients with malnutrition (AUC = 0.76), including pyroglutamine and hypoxanthine. Using pathway enrichment analysis, we identified a critical role of glutathione and purine metabolism in predicting nutrition. Nutrition status was associated with 28-day mortality, even after adjustment for known phenotypic variables associated with ICU mortality. Importantly, 7 metabolites associated with nutrition status were also associated with 28-day mortality.

CONCLUSION

Malnutrition is associated with differential metabolic profiles early in critical illness. Common to all of our metabolome analyses, glutathione and purine metabolism, which play principal roles in cellular redox regulation and accelerated tissue adenosine triphosphate degradation, respectively, were significantly altered with malnutrition.

Serum creatinine level, a surrogate of muscle mass, predicts mortality in critically ill patients

Serum creatinine (SCr) has been widely used to estimate glomerular filtration rate (GFR). Creatinine generation could be reduced in the setting of low skeletal muscle mass. Thus, SCr has also been used as a surrogate of muscle mass. Low muscle mass is associated with reduced survival in hospitalized patients, especially in the intensive care unit (ICU) settings. Recently, studies have demonstrated high mortality in ICU patients with low admission SCr levels, reflecting that low muscle mass or malnutrition, are associated with increased mortality. However, SCr levels can also be influenced by multiple GFR- and non-GFR-related factors including age, diet, exercise, stress, pregnancy, and kidney disease. Imaging techniques, such as computed tomography (CT) and ultrasound, have recently been studied for muscle mass assessment and demonstrated promising data. This article aims to present the perspectives of the uses of SCr and other methods for prediction of muscle mass and outcomes of ICU patients.