Prevalence of obesity in an intensive care unit patient population

The obesity paradox and 90 day mortality in chronic critically ill patients: a cohort study using a large clinical database

BACKGROUND

This study investigates the obesity paradox, where obesity is linked to lower mortality in certain patient groups, focusing on its impact on long-term mortality in chronic critically ill (CCI) patients.

METHODS

We retrospectively analyzed CCI patients from the Medical Information Mart for Intensive Care-IV (MIMIC-IV) database's Intensive Care Unit, categorizing them into six groups based on Body Mass Index (BMI). Using stepwise multivariable Cox regression and restricted cubic spline models, we examined the association between BMI and 90 day mortality, accounting for confounding variables through subgroup analyses.

RESULTS

The study included 1996 CCI patients, revealing a 90 day mortality of 34.12%. Overweight and obese patients exhibited significantly lower mortality compared to normal-weight individuals. Adjusted analysis showed lower mortality risks in overweight and obese groups (HRs 0.60 to 0.72, p < 0.001). The cubic spline model indicated a negative correlation between BMI and 90 day mortality, with subgroup analyses highlighting interactions with age.

CONCLUSION

Our findings confirm the obesity paradox in CCI patients, especially among the elderly (65-85 years) and very elderly (≥ 85 years). The results suggest a beneficial association of higher BMI in older CCI patients, though caution is advised for those under 45.

Obesity Alters cytokine signaling and gut microbiome in septic mice

Sepsis is a leading cause of mortality. Plasma cytokine levels may identify those at increased risk of mortality from sepsis. Our aim was to understand how obesity alters cytokine levels during early sepsis and its correlation with survival. Six-week-old C57BL/6 male mice were randomized to control (non-obese) or high fat diet (obese) for 5-7 weeks. Sepsis was induced by cecal ligation and perforation (CLP). Cytokine levels were measured from cheek bleeds 8 h after CLP, and mice were monitored for survival. Other cohorts were sacrificed 1 h after CLP for plasma and tissue. Septic obese mice had higher survival. At 8 h after sepsis, obese mice had higher adiponectin, leptin, and resistin but lower TNFα and IL-6 compared to non-obese mice. When stratified by 24-h survival, adipokines were not significantly different in obese and non-obese mice. TNFα and IL-6 were higher in non-obese, compared to obese, mice that died within 24 h of sepsis. Diet and to sepsis significantly impacted the cecal microbiome. IL-6 is a prognostic biomarker during early sepsis in non-obese and obese mice. A plausible mechanism for the survival difference in non-obese and obese mice may be the difference in gut microbiome and its evolution during sepsis.

Mortality in Patients with Obesity and Acute Respiratory Distress Syndrome Receiving Extracorporeal Membrane Oxygenation: The Multicenter ECMObesity Study

Rationale: Patients with obesity are at increased risk for developing acute respiratory distress syndrome (ARDS). Some centers consider obesity a relative contraindication to receiving extracorporeal membrane oxygenation (ECMO) support, despite growing implementation of ECMO for ARDS in the general population. Objectives: To investigate the association between obesity and mortality in patients with ARDS receiving ECMO. Methods: In this large, international, multicenter, retrospective cohort study, we evaluated the association of obesity, defined as body mass index ⩾ 30 kg/m2, with ICU mortality in patients receiving ECMO for ARDS by performing adjusted multivariable logistic regression and propensity score matching. Measurements and Main Results: Of 790 patients with ARDS receiving ECMO in our study, 320 had obesity. Of those, 24.1% died in the ICU, compared with 35.3% of patients without obesity (P < 0.001). In adjusted models, obesity was associated with lower ICU mortality (odds ratio, 0.63 [95% confidence interval, 0.43-0.93]; P = 0.018). Examined as a continuous variable, higher body mass index was associated with decreased ICU mortality in multivariable regression (odds ratio, 0.97 [95% confidence interval, 0.95-1.00]; P = 0.023). In propensity score matching of 199 patients with obesity to 199 patients without, patients with obesity had a lower probability of ICU death than those without (22.6% vs. 35.2%; P = 0.007). Conclusions: Among patients receiving ECMO for ARDS, those with obesity had lower ICU mortality than patients without obesity in multivariable and propensity score matching analyses. Our findings support the notion that obesity should not be considered a general contraindication to ECMO.

The relationship between obesity and nursing care problems in intensive care patients in Austria

OBJECTIVES

To describe the characteristics and nursing care problems of intensive care patients in Austria stratified by obesity.

BACKGROUND

Obese people in intensive care units (ICUs) present nurses with special challenges. Therefore, nurses need to receive education and training regarding how to treat obese patients to provide them with the best care. Most studies on obesity in ICU patients have not specifically addressed the problems and challenges from the nurses' perspective. This may be because nursing science programmes in Europe rarely introduce the topic of obesity.

DESIGN

This was a secondary data analysis of a longitudinal study.

METHODOLOGY

The "Nursing Quality Measurement 2.0" is the Austrian version of the "International Prevalence Measurement of Care problems". It is an annual cross-sectional study, which has been carried out since 2009. Data from all ICU patients for 2009 to 2018 were extracted and combined into one file (n = 460). The main outcome measures were obesity and various nursing care problems, including care dependency.

RESULTS

Of the ICU patients. 25% were obese. Obese ICU patients suffered significantly more often from diabetes mellitus and endocrine, nutritional, or metabolic diseases than non-obese patients. About 30% of the ICU patients were totally care dependent, and 85.6% of the ICU patients were at risk of developing pressure ulcers, whereas the risk was higher for non-obese than obese patients. ICU patients with a risk of pressure ulcer (measured with the Braden Scale) had a reduced risk of being obese (OR = 0.544).

CONCLUSION

Overall, the prevalence of nursing care problems found in this study was high. No significant differences in the prevalence of nursing care problems between obese and non-obese patients were found. However, because of the increase in the number of obese patients in all nursing settings, a stronger focus on obesity research in the area of nursing science is recommended.

Obesity and the Survival of Critically Ill Patients with Acute Kidney Injury: A Paradox within the Paradox?

The obesity epidemic is reflected by the rising number of obese patients requiring intensive care. Obesity is a recognized risk factor for the development of acute kidney injury (AKI) in critically ill patients. Both acute critical illness and AKI are associated with higher in-hospital mortality rates, and intensive care unit (ICU) patients suffering from AKI have an elevated risk of death. The relationships between obesity and mortality in critically ill paediatric and adult patients with or without AKI are less clear. Conflicting evidence exists regarding the potential impact of body mass index on the mortality of ICU patients with AKI. Some studies looking at the ICU outcomes of critically ill obese patients with AKI show reduced mortality and others show either no association or elevated mortality. Despite a high biologic plausibility of the proposed causal mechanisms, such as a greater haemodynamic stability and the protective cytokine, adipokine, and lipoprotein defence profiles associated with obesity, the inconsistency of the data suggests that the obesity paradox is a statistical fallacy and the result of chance, bias, and residual confounding variables in retrospective cohort analyses. Further prospective randomized trials are essential to elucidate the role of obesity and the mechanisms underlying a potential survival benefit of obesity in critically ill patients with AKI.

Diabetes-Specific Formulae Versus Standard Formulae as Enteral Nutrition to Treat Hyperglycemia in Critically Ill Patients: Protocol for a Randomized Controlled Feasibility Trial

Background

During critical illness, hyperglycemia is prevalent and is associated with adverse outcomes. While treating hyperglycemia with insulin reduces morbidity and mortality, it increases glycemic variability and hypoglycemia risk, both of which have been associated with an increase in mortality. Therefore, other interventions which improve glycemic control, without these complications should be explored. Nutrition forms part of standard care, but the carbohydrate load of these formulations has the potential to exacerbate hyperglycemia. Specific diabetic-formulae with a lesser proportion of carbohydrate are available, and these formulae are postulated to limit glycemic excursions and reduce patients’ requirements for exogenous insulin.

Objective

The primary outcome of this prospective, blinded, single center, randomized controlled trial is to determine whether a diabetes-specific formula reduces exogenous insulin administration. Key secondary outcomes include the feasibility of study processes as well as glycemic variability.

Methods

Critically ill patients will be eligible if insulin is administered whilst receiving exclusively liquid enteral nutrition. Participants will be randomized to receive a control formula, or a diabetes-specific, low glycemic index, low in carbohydrate study formula. Additionally, a third group of patients will receive a second diabetes-specific, low glycemic index study formula, as part of a sub-study to evaluate its effect on biomarkers. This intervention group (n=12) will form part of recruitment to a nested cohort study with blood and urine samples collected at randomization and 48 hours later for the first 12 participants in each group with a secondary objective of exploring the metabolic implications of a change in nutrition formula. Data on relevant medication and infusions, nutrition provision and glucose control will be collected to a maximum of 48 hours post randomization. Baseline patient characteristics and anthropometric measures will be recorded. A 28-day phone follow-up will explore weight and appetite changes as well as blood glucose control pre and post intensive care unit (ICU) discharge.

Results

Recruitment commenced in February 2015 with an estimated completion date for data collection by May 2018. Results are expected to be available late 2018.

Conclusions

This feasibility study of the effect of diabetes-specific formulae on the administration of insulin in critically ill patients and will inform the design of a larger, multi-center trial.

Trial Registration

Australian New Zealand Clinical Trial Registry (ANZCTR):12614000166673; https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?ACTRN=12614000166673 (Archived by WebCite at http://www.webcitation.org/6xs0phrVu)

Prevalence of obesity and the effect on length of mechanical ventilation and length of stay in intensive care patients: A single site observational study

OBJECTIVES

To provide a snapshot of the prevalence of abnormal body mass index (BMI) in a sample of intensive care unit (ICU) patients; to identify if any medical specialty was associated with abnormal BMI and to explore associations between BMI and ICU-related outcomes.

BACKGROUND

Obesity is an escalating public health issue across developed nations but there is little data pertaining to critically ill patients who require care that is expensive.

METHODS

Retrospective observational audit of 735 adult patients (median age 58 years) admitted to the Sir Charles Gairdner Hospital 23 bed tertiary ICU between November 2012 and June 2014. Primary outcome measure was patient BMI: underweight (<18.5kg/m²), normal weight (18.5-24.99kg/m²), overweight (25-29.99kg/m²), obese (30-39.99kg/m²) or extreme obese (40kg/m² or above). Other measures included gender, acute physiology and chronic health evaluation II score, admission specialty, length of mechanical ventilation (MV), length of stay (LOS) and mortality.

RESULTS

Compared to the general population there was a higher proportion of obese patients within the cohort with the majority of patients overweight (33.9%) or obese (36.5%) and median BMI of 27.9 (IQR 7.9). There were no significant differences between specialties for BMI (p=0.103) and abnormal BMI was not found to impact negatively on mortality (ICU, p=0.373; hospital, p=0.330). Normal BMI patients had shorter length of MV than other BMI categories and the impact of BMI on ICU LOS was dependent on length of MV. Overweight patients ventilated for five days or more had a shorter LOS, and extremely obese non-ventilated patients had a longer LOS, compared to normal weight patients.

CONCLUSIONS

Although the obesity-disease relationship is increasingly complex and data presented reflects categorical BMI for patients admitted to a single ICU site it may be important to consider the cost implications of caring for this cohort especially with regard to MV and LOS.