Influence of Calorie Protein Delivery on Outcomes and Body Composition. Changes in the Intensive Care Unit. Sarah Peterson

Influence of Calorie Protein Delivery on Outcomes and Body Composition Changes in the Intensive Care Unit BY Sarah Peterson B.A., Nutrition and Dietetics, The College of St. Scholastica, Duluth, MN 1999 M.S., Clinical Nutrition, Rush University, Chicago, IL 2002 Dissertation Submitted as partial fulfillment of the requirements for the degree of Doctor of Philosophy in Kinesiology, Nutrition and Rehabilitation Sciences in the Graduate College of the University of Illinois at Chicago, 2015 Defense Committee: Carol Braunschweig, PhD, RD Chair and Advisor Giamila Fantuzzi, PhD Sally Freels, PhD; Biostatistics Jake Haus, PhD Omar Lateef, DO; Rush University Medical Center

TABLE OF CONTENTS I. REVIEW OF LITERATURE... 1 A. Outcomes Linked with Provision of Increased Calorie and Protein Delivery... 2 A.1. Results from Observational Cohorts... 2 A.2. Results from Prospective Randomized Controlled Trials... 6 A.3. Postulated Mechanism Relating Calorie and Protein Delivery to Worse Outcomes in the Intensive Care Unit...16 A.3.a. Estimation of Calorie and Protein Requirements...16 A.3.b. Blood Glucose Control...20 A.3.c. Study Population and Setting...20 A.3.d. Summary of Calorie and Protein Delivery...22 B. Body Composition in the Intensive Care Unit...22 B.1. Sarcopenic Obesity...22 B.1.a. Prevalence of Sarcopenia Defined by Diagnostic Abdominal Computed Tomography...25 B.1.b. Consequences of Sarcopenic Obesity...28 B.1.c. Summary of Sarcopenia...31 B.2. Changes in Body Composition during Critical Illness...31 B.2.a. Change in Muscle and Adipose Depots Measured by In vivo Neutron Activation Analysis/Dual-Energy X-ray Absorptiometry...31 B.2.b. Change in Muscle Depots Measured by Ultrasound...35 B.2.c. Change in Muscle and Adipose Depots Computed Tomography...37 B.2.e. Summary of Muscle/Adipose Depots...41 II. METHODS...43 A. Study Design...43 B. Study Population and Setting...43 B.1. Nutrition Exposure Assessment Time Frame...44 C. Data Collection...45 C.1. Demographics/Medical Information...45 C.2. Severity of Illness...45 C.3. Nutritional Status...46 C.4. Nutrition Support Delivery...46 C.5. Laboratory Values...46 C.6. Clinical Variables...47 C.7. Computed Tomography Data...48 C.8. Outcome Variables...49 D. Fidelity of Data Collection...50 F. Results from the INTACT Post-Hoc Study...50 G. Statistical Analysis...52 G.1. Statistical Analysis for Specific Aim One...52 G.2. Statistical Analysis for Specific Aim Two...54 G.3. Statistical Analysis for Specific Aim Three...56 III. RESULTS...59 A. Summary of Demographic/Baseline Data, Average Daily Calorie and Protein Delivery and Intensive Care Unit Outcomes...59 B. Results for Specific Aim One...66 B.1. Primary Outcome: Mortality...66 B.2. Secondary Outcomes: Mechanical Ventilation, Length of Stay and Infection...67 C. Results for Specific Aim Two...75 C.1. Prevalence of Sarcopenic and Influence on Primary and Secondary Outcomes...75 C.2. Misclassification between Sarcopenia and Subjective Global Assessment...76 ii

C.3. Influence of Calorie Delivery on Mechanical Ventilation, Length of Stay, Infection and Mortality among Sarcopenic Patients...77 D. Results for Specific Aim Three...85 D1. Change in Skeletal muscle and Adipose Depots...85 D2. Prediction of Percent Changes in Skeletal Muscle and Adipose Depots per Day...86 IV. DISCUSSION...94 A. Discussion for Specific Aim One...94 A.1. Relationship between Calorie Exposure and Mortality Observed in the Current Study and INTACT...94 A.2. Relationship between Calorie Exposure and Mortality Observed in Clinical Trials... 100 A.3. Relationship between Calorie Exposure and Mortality Observed in Observational Studies... 106 A.4. Relationship between Calorie Exposure and Secondary Outcomes... 110 Mechanical ventilation... 110 ICU and hospital length of stay... 114 Infectious complications... 116 B. Discussion for Specific Aim Two... 120 B.1. Prevalence and Characteristics of Sarcopenic Patients... 120 B.2. Consequences of Sarcopenia... 124 C. Discussion for Specific Aim Three... 130 C.1. Changes in Skeletal Muscle Cross-Sectional Area... 130 C.2. Impact of Calorie and Protein on Skeletal Muscle Change... 131 C.3. Adipose Depots... 135 C.3.a. Visceral Adipose Tissue... 135 C.3.b. Intramuscular Adipose Tissue... 135 C.3.c.Subcutaneous Adipose Tissue... 136 D. Limitations of the Current Research... 137 E. Conclusion... 138 F. Implications for Future Research... 140 V. REFERENCES... 142 APPENDIX A: Approval of Research... 161 APPENDIX B: Intensive Nutrition in ARDS: A Clinical Trial (INTACT) grant... 164 VITA... 184 iii

LIST OF TABLES Table I: Description of study design and demographic characteristics among recent prospective randomized controlled trials evaluating effect of aggressive calorie delivery in the ICU... 7 Table II: Outcomes with calorie delivery in the ICU reported by recent clinical trials... 9 Table III: Standardization of calorie and protein delivery across recent prospective randomized clinical trials evaluating effect of aggressive calorie delivery in the ICU...18 Table IV: Relationship between body mass index and intensive care outcome...23 Table V: Agreement between measured and estimated energy expenditure among critically ill obese patients...29 Table VI: Description of body composition changes among patients in the ICU...32 Table VII: Summary of demographic and severity of illness characteristics for the ENP study sample of 298 patients with ALI...62 Table VIII: Daily calorie and protein prescription and average daily delivery for the ENP study sample of 298 patients with ALI...63 Table IX: Summary of primary and secondary outcomes for the ENP (n=298) patients with ALI...64 Table X: Comparison of demographic and severity of illness characteristics between INTACT subjects and the ENP (n=298) patients with ALI...65 Table XI: Demographic and outcome data for all patients with ALI and comparison of demographic and outcome data between those who received less than 18 versus greater/equal 18 calories/kg...69 Table XII: Calorie delivery and sample size for patients who discharged alive versus died in the ICU...70 Table XIII: Comparison of demographic and outcome data between those who discharged alive versus died in the ICU...71 Table XIV: Logistic regression model of mortality (yes/no) with average Kcal/Kg delivery and significant predictors (n=298)...72 Table XV: Relationship between likelihood of death with average Kcal/Kg delivery over increasing study days, modeled via logistic regression^...72 Table XVI: Linear regression model of duration of mechanical ventilation with average Kcal/Kg delivery and significant predictors (n=298)...73 Table XVII: Linear regression model of ICU length of stay with average Kcal/Kg delivery and significant predictors (n=298)...73 iv

Table XVIII: Linear regression model of hospital length of stay with average Kcal/Kg delivery and significant predictors (n=298)...74 Table XIX: Logistic regression model of total infections (yes/no) with average Kcal/Kg delivery (n=298)...74 Table XX: Demographic/severity of illness characteristics and ICU outcomes for the ENP patients with a baseline L3 CT and comparison of variables between sarcopenic versus nonsarcopenic patients...79 Table XXI: Linear regression model of duration of mechanical ventilation with difference between dosing weight-elbm and significant predictors among ENP patients with a baseline L3 CT scan (n=95)...80 Table XXII: Linear regression model of ICU length of stay with difference between dosing weight-elbm and significant predictors among ENP patients with a baseline L3 CT scan (n=95)...80 Table XXIII: Linear regression model of hospital length of stay with difference between dosing weight-elbm and significant predictors among ENP patients with a baseline L3 CT scan (n=95)...81 Table XXIV: Comparison of demographic/severity of illness and calorie and protein delivery in sarcopenic patients misclassified as normally nourished, non-sarcopenic patients classified as normally nourished and sarcopenic patients classified as moderately/severely malnourished via SGA among ENP patients with a baseline L3 CT scan...82 Table XXV: Linear regression model of duration of mechanical ventilation with average Kcal/ELBM, difference between dosing weight-elbm and significant predictors among ENP patients with a baseline L3 CT scan (n=95)...83 Table XXVI: Linear regression model of ICU length of stay with average Kcal/ELBM delivery, difference between dosing weight-elbm, proportion of ICU length of stay that nutrient intake was not known and significant predictors among ENP patients with a baseline L3 CT scan (n=95)...83 Table XXVII: Linear regression model of hospital length of stay with average Kcal/ELBM delivery, difference between dosing weight-elbm and significant predictors among ENP patients with a baseline L3 CT scan (n=95)...84 Table XXVIII: Demographic, severity of illness characteristics, calorie and protein delivery and body composition depots for the ENP patients with two L3 CT scans^...89 Table XXIX: Mean difference (SD) of skeletal muscle, intermuscular adipose tissue (IMAT) and visceral adipose tissue and skeletal muscle attenuation between CT1 and CT2 (N = 37)...90 Table XXX: Linear regression model of skeletal muscle cross-sectional area percent loss per day with calorie delivery and significant predictors among ENP patients with two L3 CT scans (n = 37)...91 v

Table XXXI: Linear regression model of skeletal muscle cross-sectional area percent loss per day with protein delivery and significant predictors among ENP patients with two L3 CT scans (n = 37)...91 Table XXXII: Linear regression of skeletal muscle cross-sectional area percent loss per day among ENP patients with two L3 CT scans both completed within 8 days of study enrollment (n=8)...92 Table XXXIII: Linear regression model of calorie delivery and skeletal muscle cross-sectional area percent loss per day among ENP patients with two L3 CT scans both completed after 7 days of study enrollment (n=9)...92 Table XXXIV: Linear regression model of protein delivery and skeletal muscle cross-sectional area percent loss per day among ENP patients with two L3 CT scans both completed after 7 days of study enrollment (n=9)...92 Table XXXV: Linear regression model of IMAT cross-sectional area percent loss per day among ENP patients with a baseline L3 CT scan with two L3 CT scans (n=37)...93 Table XXXVI: Linear regression model of visceral cross-sectional area percent loss per day among ENP patients with a baseline L3 CT scan with two L3 CT scans (n = 37)...93 Table XXXVII: Linear regression model of skeletal muscle Hounsfield unit percent loss per day among ENP patients with a baseline L3 CT scan with two L3 CT scans (n = 37)...93 vi

LIST OF FIGURES Figure 1: Flow diagram of subject eligibility...61 Figure 2: Estimation of daily calorie prescription of feeding clinical trials in the ICU... 102 vii

LIST OF ABBREVIATIONS ALI/ARDS Acute lung injury/acute respiratory distress syndrome APACHE II Acute Physiology and Chronic Health Evaluation II BMI Body mass index CT Computed tomography DXA Dual x-ray absorptiometry ELBM Estimated lean body mass EN Enteral nutrition ENP Eligible non-participating patients IBW Ideal body weight ICU Intensive care unit IMAT Intramuscular adipose tissue INTACT Intensive Nutrition in Acute Lung Injury viii

IVNAA In vivo neutron activation analysis Kcal/Kg Calories per kilogram L3 Third lumbar region mg/dl milligrams per deciliter PaO2/FiO2 ratio of partial pressure arterial oxygen and fraction of inspired oxygen PN Parenteral nutrition PRCT Prospective randomized controlled trial REE Resting energy expenditure SAPS Simplified acute physiology score SGA Subjective global assessment SMI Skeletal muscle index SOFA Sequential organ failure assessment VAT Visceral adipose tissue ix

I. SUMMARY A. Overview Non-volitional enteral (EN) and parenteral nutrition (PN) is provided to critically ill patients under the assumption that the increased nutrient delivery improves clinical outcomes. 1-3 However, prospective randomized controlled trials (PRCT) published over the past four years have raised doubts regarding the benefits of this therapy within Intensive Care Unit (ICU) populations. 4-12 Our research group conducted a PRCT (Intensive Nutrition in Acute Lung Injury (ALI/ARDS): A Clinical Trial (INTACT) 4, Clinicaltrial.gov Identifier: R01HL093142-04) to assess the impact of intensive medical nutrition therapy from diagnosis of ALI through hospital discharge versus standard care on clinical outcomes. The outcomes assessed included infections, changes in immune parameters, duration of mechanical ventilation, ICU/hospital length of stay and mortality. After enrolling 78 subjects (40 intervention, 38 control) the trial was stopped early due to significantly higher mortality in the intervention group (16/40, 40% versus 6/38, 16%). Randomization resulted in equal distribution of demographic and severity of illness characteristics between groups. The percent of estimated energy and protein requirements delivered was significantly higher in participants randomized to the intervention compared to the control group. Specifically, participants in the intervention group received 1798 calories ± 509 (85% of requirements/25.4 calories per kilogram (Kcal/kg)) and controls received 1221 calories ± 423 (55% of requirements/16.6 Kcal/kg; p<0.0001). The intervention group received 82.0 grams ± 23 and controls received 60.4 grams ± 24 protein (p<0.0001). 4 The outcome of our research corroborates findings from three recently published PRCTs 5-7 that reported worse ICU outcomes with significantly higher calorie delivery in the intervention groups. However, dissimilarities in patient populations (severity of illness, medical ICU versus medical/surgical ICU, single as opposed to multicenter) and inconsistencies in calorie and protein prescription (specifically the different prediction equations utilized to estimate daily calorie and protein requirement) make it difficult to generalize findings between studies. x

A post-hoc study of the INTACT data was recently completed to further explore the characteristics of participants who died vs survived and discern the impact of the dose of Kcal/Kg received and timing on mortality risks. We observed (1) increased nutrition support delivery increased overall likelihood of death; (2) timing of calorie delivery influenced the relationship between energy exposure and mortality, Kcal/Kg received during days 1-7 increased hazards of subsequent death for days 8+ while Kcal/Kg received on days 8+ were associated with lower hazard of death and (3) exposure to more than 18 Kcal/Kg during days 1-7 significantly increased the likelihood of death on day 8+. Despite these highly significant and consistent findings of the INTACT trial and post-hoc study, the early termination and small sample size raise concerns these findings are a reflection of a type I statistical error. In an attempt to discern if these results could be reproduced in a larger similar population the current retrospective cohort study was conducted. The first aim of the current study was to further explore the associations between calorie exposure and timing of delivery with ICU outcomes in a cohort of 298 ICU patients who had been prospectively identified as eligible for INTACT, based on severity of illness, baseline biochemistry profiles and nutritional status, but were not enrolled (eligible non-participating (ENP) patients). Mortality within this group was 33%, a rate similar to the overall rate (28%, 22/78) in the INTACT trail. Data for medical records were collected to explore the associations between the exposure to calorie and protein intake and iatrogenic infections, mechanical ventilation duration and length of stay. We recently reported a 60% prevalence of sarcopenia in a convenience sample of critically ill respiratory patients with a diagnostic abdominal computed tomography (CT) completed while in the ICU. 13 Notably, sarcopenia was not detected by subjective global assessment (SGA), the nutrition assessment tool considered to be the gold standard for hospitalized patients. 14 Within this sample, 60% (18/30) of patients classified as normally nourished by SGA were sarcopenic; 67% of these misclassified patients were overweight (6/18) xi

or obese (6/18). Accurately predicting energy and protein requirements in all ICU patients is difficult, particularly among overweight/obese patients. When sarcopenia accompanies obesity/overweight and is not detected the estimations of energy and protein needs will exceed actual requirements due to the depletion of lean body mass. We propose the greater mortality found in our INTACT trial may have occurred by our failure to detect these overweight/obese sarcopenic individuals leading to subsequent over prescription and delivery of nutritional support. To investigate this relationship the second specific aim of the current study assessed the prevalence of low muscle mass and outcomes associated with calorie delivery in 95 ENP patients with a diagnostic abdominal CT scan completed within four days of INTACT eligibility. The impact of feeding ICU patients on body depots of skeletal muscle and adipose tissue has not been previously assessed in a PRCT. Sequential diagnostic abdominal CT scans have been utilized to describe these body composition changes in various patient populations. 15-23 We recently reported changes in muscle, visceral adipose tissue (VAT) and intramuscular fat (IMAT) depots associated with nutrition support delivery in a convenience sample of 33 ICU patients that had two abdominal CT scans completed while hospitalized. 24 These exploratory results revealed a 0.49% decline per day in skeletal muscle and energy delivery between CT scans was the only significant predictor of this change. No change in VAT or IMAT depots was observed between scans. The third aim of the current study expanded these preliminary results to describe the relationship between calorie and protein delivery with changes to muscle and fat depots in a subset of 37 patients who had two diagnostic abdominal CT scans completed while receiving nutrition support in the ICU. The overall objective of this research proposal is to describe the relationship between calorie and protein delivery, ICU outcomes, and body composition changes. Our central hypothesis was that a higher percentage of estimated energy/protein provision is associated with higher morbidity/mortality, particularly in sarcopenic ICU patients that were misclassified as normally nourished. Additionally, we hypothesize that calorie and protein delivery influences the xii

rate of change in muscle and fat depots. We objectively tested our hypothesis by pursing the following specific aims: Specific Aim One To determine if exposure to elevated energy delivery via nutrition support is associated with higher morbidity and mortality rates among a large cohort of ICU patients prospectively identified as eligible for INTACT but not enrolled (ENP patients). Hypothesis: Increasing average Kcal/kg (dosing weight) delivery will increase mortality and result in longer duration of mechanical ventilation, prolonged hospital and ICU length of stay, more infectious complications and more blood glucose complications. Specific Aim Two To discern the prevalence of sarcopenia and the influence of increased energy delivery among sarcopenic patients on morbidity and mortality rates within a subset of patients who have an abdominal CT scan during hospitalization Hypothesis 2a: At least 50% of patients will be classified as sarcopenic Hypothesis 2b: At least 50% of patients with sarcopenia will not have been identified by SGA as malnourished Hypothesis 2c: Sarcopenic patients who received greater than 18 Kcal/Kg (dosing weight) will have higher mortality rates compared to sarcopenic patients who received less than 18 Kcal/Kg. Specific Aim Three To describe changes in abdominal skeletal muscle and adipose depots in relation to energy/protein delivery in a subset of patients with two or more abdominal CT scans. Hypothesis 3a: Patients who received less than 18 Kcal/Kg (dosing weight) of estimated energy needs will have greater loss of skeletal muscle cross-sectional area compared to those receiving greater than 18 Kcal/Kg xiii

Hypothesis 3b: Patients who received greater than 18 Kcal/Kg of estimated energy needs will have greater increase of IMAT and VAT cross-sectional area compared to those who received less than 18 Kcal/Kg xiv

I. REVIEW OF LITERATURE The depletion in muscle depots that occurs in critical illness has been attributed to low calorie and protein intake and viewed as an obstacle to improved ICU outcomes. 25-30 This clinical dogma has been based largely on results from small clinical trials and observational studies that found significant associations between underfeeding and infectious complications, 31 prolonged duration of mechanical ventilation 1,3 and mortality. 2,32 From 2011-2013, findings from high quality PRCTs contradict the benefits of aggressive calorie delivery in the ICU. 5-9 Three PRCTs reported worse outcomes in patients randomized to receive greater percentage of daily calorie requirements from EN or PN compared to standard care, 5-7 and two found no difference in outcomes between groups. Although these trials consistently demonstrated worse outcomes or no benefit from nutrition support, the dose of calorie delivery that elicits these effects is not known. Additionally, none of the researchers reported how increasing calorie and protein delivery influenced participants nutritional status. A possible mechanism linking increased energy/protein delivery to negative outcomes may be its influence on muscle/fat depots. However, longitudinal changes to fat and muscle tissue among ICU patients have only been described in observational studies and a post-hoc analysis including a small subset of patients enrolled in a PRCT. 24,33 The following review of literature will examine outcomes and changes in body composition associated with calorie and protein delivery in the ICU. This review has been separated into two sections. The first section reviews results associated with nutrition delivery in the ICU to establish the rationale for Specific Aim One. The second section provides justification for Specific Aims Two and Three. It reviews (a) the challenges in classifying nutritional status and potential risks for worse outcome when estimating calorie and protein requirements among sarcopenic obese critically ill patients and (b) studies that explored the relationship between calorie and protein delivery and changes in muscle and fat depots among the critically ill. 1

A. Outcomes Linked with Provision of Increased Calorie and Protein Delivery A.1. Results from Observational Cohorts Observational studies describing the association between calorie delivery and ICU outcomes have reported divergent results. 1-3,31,32,34-37 There have been over 300 observational studies published since 2010 that describe the relationship between calorie delivery and outcomes in the ICU. Approximately 75 have included mortality as a primary outcome. It is not feasible or necessary to present the finding for each study. We have limited our discussion to observational studies that are frequently cited in the nutrition research to justify feeding recommendations. Specifically we have reviewed observational studies that described outcomes associated with calorie deficits 1-3 and those that included outcomes 31,32,34-37 that are explored in the current study. Villet et al. 1, Dvir et al. 3 and Faisy et al. 2 all utilized convenience samples to describe outcomes associated with calorie deficit in the ICU. Villet et al. 1 prospectively calculated daily calorie deficit for consecutive patients admitted to the surgical ICU for at least 5 days. Energy balance was calculated daily as energy delivery minus energy target (defined by indirect calorimetry for 69% of the sample and 30 Kcal/admit weight for the remainder). Cumulative energy balance was calculated at ICU discharge and multiple linear regression models were used to determine if cumulative energy balance was associated to outcome. A total of 48 patients with an average Simplified Acute Physiology Score 38 (SAPS II) score of 45 were included. Average length of stay was 15 days, however 24, 5 and 4 patients remained in the ICU for more than 2,3 and 4 weeks, respectively. Average calorie deficit during week one and four was -1270 and -625 calories per day, respectively. They concluded higher calorie deficits were associated with longer length of stay (p<0.001), more complications (p=0.0003), more days of antibiotics (p=0.003) and longer duration of mechanical ventilation. 2

Similarly, Dvir et al. 3 determined calorie deficits for ICU patients expected to require mechanical ventilation for at least 72 hours. Indirect calorimetry was conducted for all subjects and daily energy balance was calculated as daily calorie intake minus measured resting energy expenditure. The endpoint for data collection was not specified and mean days of nutrition support was not reported. Pearson correlation coefficients were used to describe the relationship among energy deficit and clinical outcome. A total of 50 patients were included with a mean Acute Physiology and Chronic Health Evaluation II 39 (APACHE II) score of 23. Patients stayed in the ICU for an average of 15 days and accrued a cumulative energy balance -4767 kcal. Increasing calorie deficit was associated with a new complication (including new renal failure/renal replacement therapy, vasopressor administration, ALI, liver failure, septic shock, unplanned surgery and new pressure wound). No relationship was observed between cumulative energy balance and duration of ventilation, length of stay or death. Finally, Faisy et al. 2 retrospectively measured calorie deficits among IUC patients requiring mechanical ventilation for at least seven days. Similar to Dvir et al. 3 indirect calorimetry was used to measure energy requirements and daily energy balance was calculated as daily calorie intake minus measured resting energy expenditure. The endpoints for data collection were not specified and mean days of nutrition support were not reported. Logistic regression models were used to determine the relationship between energy deficit and mortality. A total of 48 patients with a SAPS II score of 47 were included. Patients were in the ICU for an average of 28 days and mean energy deficit was -1300 calories per day. Mortality rates were very high (72%) and patients who died had higher mean energy deficit compared to patients discharged alive. Patients with an energy deficit of at least 1200 after 14 days had a higher mortality rate. Based on the assumption that large calorie deficits lead to worse ICU outcomes nutrition support guidelines have proposed early initiation of nutrition support to avoid long intervals if inadequate intake 40,41. However, observational studies by Krishnan et al. 34, Arabi et al. 35 and Weijs et al. 36 all reported higher mortality with increased calorie delivery. Krishnan et al. 34 3

evaluated the influence of energy delivery on outcomes in a retrospective cohort study of ICU patients recruited from a community (n=46) and tertiary care hospital (n=141). Patients were included in the study if they remained in the ICU for more than 96 hours and could not have an oral diet started. Outcome variables included mean calorie intake relative to estimated needs derived from the American College of Chest Physician guidelines of 25 calories per kilogram 42 and mortality. All feeding decisions, including route of nutrition support delivery and calorie and protein prescription, were made at the discretion of the ICU team. Patients had a median age of 54.7 years interquartile range: 43.4-70.1), body mass index (BMI) of 25.0 (19.7-30.4) and 94% required mechanical ventilation. Severity of illness was measured by SAPS II; the median score for the group was 50 (41-62), representing a predicted hospital mortality of approximately 50%. After controlling for severity of illness, nutritional status and route of nutrition support, receiving greater than 66% of estimated energy requirements was associated with a significant decrease in likelihood of discharge alive from the hospital (OR 0.82 95% CI 0.70-0.94, p<0.05) compared to patients who received less than 33%. 34 Arabi et al. 35 investigated the relationship between exposure to EN calorie and protein intake and morbidity/mortality within a nested cohort study (n=523) of patients enrolled in a PRCT designed to compare intensive versus conventional insulin therapy. Caloric target was estimated via the Harris-Benedict equation with stress factors. The average APACHE II score was 22.8 and 65% of the sample required vasopressors for hypotension. Average energy delivery was 873 ± 506 calories per day, the authors did not report Kcal/Kg and did not provide average weight for the participants. Provision of greater than 65% of calories was associated with higher hospital mortality (40% versus 21%, p=0.003), longer duration of mechanical ventilation (12.8 ± 10.4 versus 4.7 ± 7.0 days, p<0.0001), higher ICU length of stay (13.9 ± 11.4 versus 6.1 ± 6.9, p<0.0001) and more ICU-acquired infections (55% versus 18%, p<0.0001) compared to patients who received <33% of estimated energy requirements. 35 4

Weijs et al. 36 conducted a retrospective cohort of intubated ICU patients with an average APACHE II score of 23.0 to examine the relationship between calorie and protein delivery for the first four days in the ICU on mortality (n=843). Indirect calorimetry was utilized to measure resting energy expenditure; patients were categorized as overfed if average calorie delivery over ICU days 1-4/measure resting energy expenditure was greater than 1.1. Overfeeding for the first four ICU days was significantly associated with higher mortality (OR 1.62 95% CI 1.07-2.44, p=0.02). Alternatively, Alberda et al. 32 and Cahill et al. 37 observed improved survival and no difference in mortality among ICU patients, respectively. Alberda et al. 32 utilized a multi-icu cohort and described the relationship between mortality and average calorie intake. Participating ICUs enrolled patients who required mechanical intubation within the first 48 hours of admission. Daily calorie intake was recorded for a minimum of 12 days or until discharge/death. Patients (n=2722) had an average APACHE II score of 22 and a variety of admitting diagnoses (respiratory disease (including asthma/copd exacerbations, 27%), cardiovascular compromise (18%), GI (16%), neurologic impairment (12%), trauma (10%), septic (9%), and other (8%)). Patients received 1034 calories per day (59% of estimated requirements or approximately 13 Kcal/Kg). They reported a 24% reduction in mortality for every 1,000 increase in calorie delivery (OR 0.76 95% CI 0.61-0.94, p=0.01). Cahill et al. 37 utilized a similar multi-national cohort as the one described by Alberda et al. 32 and did not find an association between calorie exposure and mortality. Patients were included if they had a contraindication to early EN (n=703). The sample had a high severity of illness (APACHE II score: 25) and reason for admission included sepsis (27%), respiratory disease (24%), cardiovascular/vascular (15%), GI (12%), pancreatitis (11%), neurologic disorder (2%), trauma (2%), renal (2%), metabolic (1%) and other (2%). Patients were categorized to either the early PN (started within 48 hours of ICU admission, n=83), late PN (started 48 hours after ICU admission, n=79) or late EN (started 48 hours after ICU admission, 5

n=541) group. Average calorie delivery was determined for the first 12 days in the ICU and was significantly different between groups, the early PN, late PN and late EN groups received 17.5 ± 5.8, 13.6 ± 6.3 and 9.9 ± 5.5 Kcal/kg, respectively. No association between mortality and calorie exposure was observed. Approximately 77% of the participants were included in the late EN group (541/703). A.2. Results from Prospective Randomized Controlled Trials Between 2011 and 2013 results from six PRCTs 4-9 were available to describe the relationship between calorie delivery and ICU outcomes. Arabi et al. 5, Casaer et al. 6 and our INTACT 4 data all reported higher mortality with increasing calorie exposure. While Singer et al. 7, Rice et al. 8 and Doig et al. 9 observed no difference in mortality. Findings for these trials and the INTACT trial are summarized in TABLES I and II and additional details are described below. Based on the results of their observational study, 35 Arabi et al. 5 conducted a 2x2 factorial PRCT at a single medical/surgical ICU to examine the effect of EN calorie delivery and blood glucose control over a two year period of time. Eligibility included anticipated ICU length of stay greater than 48 hours, initiation of EN and serum glucose of greater than 110 mg/dl. Caloric target was estimated via the Harris-Benedict equation (using actual weight) with stress factors and protein requirements were estimated at 0.8-1.5 grams per kilogram. Subjects were randomized to one of four groups: (1) 60-70% EN delivery with intensive insulin therapy until ICU discharge (n=59), (2) 60-70% EN delivery with conventional insulin therapy until ICU discharged (n=61), (3) 90-100% EN nutrition delivery with intensive insulin therapy until ICU discharged (n=61) and (4) 90-100% EN nutrition delivery with conventional insulin therapy until ICU discharged (n=59). Data were analyzed via pooled analysis comparing outcomes among subjects randomized to the 90-100% intervention group (n=120) versus the 60-70% control group (n=120). Gender distribution and mean age, weight and BMI were similar between groups (TABLE I). Average APACHE II and Sequential Organ Failure Assessment 43 (SOFA) score for both groups were approximately 25 and 10, respectively, indicating an average expected 6

TABLE I: DESCRIPTION OF STUDY DESIGN AND DEMOGRAPHIC CHARACTERISTICS AMONG RECENT PROSPECTIVE RANDOMIZED CONTROLLED TRIALS EVALUATING EFFECT OF AGGRESSIVE CALORIE DELIVERY IN THE ICU Demographic characteristics INTACT 4 Arabi 5 Singer 7 Casaer 6 Rice 8 Doig 9 ALI requiring ventilation ICU, receiving enteral Expected ICU/ventilation ICU, nutrition risk screen Acute lung injury requiring ICU 2 days, no plan for Eligibility 72 hours & not immune nutrition with blood more than 3 days 3 & BMI >17 ventilation 72 hours enteral/parenteral nutrition criteria suppressed glucose 110 mg/dl & central access Setting Single ICU Single ICU Single ICU Multi-center (7 ICUs) Multi-center (44 ICUs) Multi-center (31 ICUs) Sample size Intervention: n=40 Intervention: n=120 Intervention: n=65 Intervention: n=2312 Intervention: n= 492 Intervention: n= 686 Energy Requirement Control: n=38 30 calorie per kilogram of dosing body weight Dosing body weight: BMI<25=actual weight BMI>25=(actual weigh ideal body weight) x 0.25 + ideal body weight Control: n=120 Intervention: prescribed 90-100% Harris-Benedict equation with stress factor Control: prescribed 60-70% Harris-Benedict equation with stress factor Control: n=65 Intervention: indirect calorimetry Control: 25 calorie per kilogram of pre-admit weight Control: n=2328 Dosing weight x caloric need Dosing weight BMI< 18.5 = (ideal body weight + actual)/2 BMI 18.5-27= ideal body weight BMI >27= ideal body weight x 1.2 Control: n=508 25-30 calorie per kilogram of ideal body weight/day of non-protein energy Control: n=686 Harris-Benedict with stress factor dosing weight: BMI <30 =actual weight BMI = calorie per kilogram (BMI=21) Calories goals were capped at 35 calorie per kilogram Protein Requirement Intervention protocol 1.2-1.5 grams protein per kilogram of dosing body weight >80% of calories delivered via EN or PN until hospital discharge 0.8-1.5 grams protein per kilogram 90-100% of calories via enteral nutrition until ICU discharge Caloric need: female >60 years=24 female 60 years=30 male >60 years=30 male 60 years=36 Protein goal not set Protein goal not set 1.2-1.6 grams protein per ideal body weight EN and PN to reach REE until ICU discharge EN and PN until ICU discharge Goal EN first 6 study days 1.0-1.5 grams protein per kilogram EN and PN started, goal by ICU day 3 until ICU discharge Control protocol Age Gender (%male) Severity of illness Standard care until hospital discharge Intervention: 52.5 ± 17.1 Control: 58.6 ± 16.2 Intervention: 49% Control: 55% APACHE II Intervention: 23.4 ± 9.3 Control: 27.7 ± 7.9 SOFA Intervention: 9.6 ± 3.5 Control: 10.0 ± 3.8 60-70% of calories via enteral nutrition until ICU discharge Intervention: 50.3 ± 21.3 Control: 51.9 ± 22.1 Intervention: 65% Control: 72% APACHE II Intervention: 25.2 ± 7.5 Control: 25.3 ± 8.2 SOFA Intervention: 10.3 ± 3.3 control: 10.2 ± 3.3 Standard care until ICU discharge Intervention: 59 ± 18 Control: 62 ± 17 Intervention: 54% Control: 63% APACHE II Intervention: 22.1 ± 7.4 Control: 22.4 ± 6.8 SOFA Intervention: 6.4 ± 2.9 Control: 6.6 ± 3.5 EN and 5% dextrose until ICU discharge, PN after 7 day until ICU discharge Intervention: 64 ± 15 Control: 64 ± 14 Intervention: 64% Control: 64% APACHE II Intervention: 23 ± 10 Control: 23 ± 11 Trophic enteral nutrition first 6 study days Intervention: 52 ± 16 Control: 52 ± 17 Intervention: 49% Control: 53% APACHE III Intervention: 90 ± 27 Control: 92 ± 28 SOFA not measured Nutrition support per ICU team until ICU discharge Intervention: 68.4 ± 15.1 Control: 68.6 ± 14.3 Intervention: 59% Control: 62% APACHE II Intervention: 20.5 ± 7.4 Control: 21.5 ± 7.8 7

Demographic characteristics Mechanical ventilation Weight (kg) BMI (kilogram/ meter 2 ) INTACT 4 Arabi 5 Singer 7 Casaer 6 Rice 8 Doig 9 Intervention: 100% Control: 100% Intervention: 86.3 ± 27.6 Control: 88.6 ± 27.2 Intervention: 29.8 ± 9.3 Control: 30.1 ± 8.9 Intervention: 99% Control: 99% Intervention: 76.3 ± 21.1 Control: 77.0 ± 17.8 Intervention: 28.5 ± 7.4 Control: 28.5 ± 8.4 Intervention: 100% Control: 100% Intervention: 79.8 ± 19.5 Control: 78 ± 18.2 Intervention: 27.8 ± 6.3 Control: 27.4 ± 7.3 Intervention: 36% Control: 40% Intervention: 76 ± 16 Control: 75 ± 15 Intervention: BMI <20:6% BMI 20-25: 38% BMI 25-30: 37% BMI 30-40: 17% BMI >40: 1% Control: BMI <20:6% BMI 20-25: 37% BMI 25-30: 37% BMI 30-40: 17% BMI >40: 2% Intervention: 100% Control: 100% Intervention: 87.0 ± 25.8 Control: 85.9 ± 23.5 Intervention: 30.4 ± 8.2 Control: 29.9 ± 7.8 Intervention: 81% Control: 84% Weight not provided Intervention: 27.9 ± 6.8 Control: 28.5 ± 6.9 8

TABLE II: OUTCOMES WITH CALORIE DELIVERY IN THE ICU REPORTED BY RECENT CLINICAL TRIALS Outcome Variables Infectious complications Duration of mechanical ventilation ICU Length of stay (LOS) Hospital Length of stay (LOS) Mortality Mean daily calorie requirement Mean calorie delivery Mean calorie per kilogram delivery Mean percent energy delivery Mean daily protein requirement (grams) INTACT 4 Arabi 5 Singer 7 Casaer 6 Rice 8 Doig 9 No difference between groups No difference between groups No difference between groups No difference between groups Intervention group had higher mortality (39% vs. 16%, p=0.02) Estimated Intervention: 2056.4± 333.6 Control: 2056.5 ± 315.1 Intervention: 1797.7 ± 509.3 Control: 1221.7 ± 422.9 No difference between groups No difference between groups No difference between groups No difference between groups Intervention group had higher mortality (42.5% vs. 30%, RR: 0.71 95% CI 0.50-0.99, p<0.05) Estimated Intervention: 1767.6 ± 311.3 Control: 1833.0 ± 335.8 Intervention: 1251.7 ± 432.5 Control: 1066.6 ± 306.1 Intervention group had more infection (57% vs. 31%, p<0.05) Intervention group had longer duration mechanical ventilation (16.1 ± 14.7 vs. 10.5 ± 8.3 days, p=0.03) Intervention group had higher ICU LOS (17.2 ± 14.6 vs. 11.7 ± 8.4, p=0.04) not primary outcome Intervention group had trend toward lower hospital mortality (32% vs. 48%, p=0.058) Measured Intervention: 1976 ± 468 Control: 1838 ± 468 Intervention: 2086 ± 460 Control: 1480 ± 356 data not reported data not reported data not reported Intervention: 88.4 ± 23.8% Control: 60 ± 21.5% Intervention: 108.8 ±19.7 Control: 111 ± 17.2 Intervention: 71.4 ± 22.8% Control: 59.0 ± 16.1% Intervention: 69.1 ± 14.5 Control: 74.1 ± 17.8 Intervention: 2086/1976 = 106% Control: 1480/1838 = 81% Intervention group had more infections (26% vs. 23%, p=0.008) Intervention group had higher proportion of patients requiring MV more than 2 days (40% vs. 36%, p=0.006) Intervention group longer ICU LOS (median 4 (2-9) vs. 3 (2-7) days, p=0.02) Intervention group longer hospital LOS (median 16 (9-29) vs. 14 (9-27) days, p=0.004) No difference between groups not primary outcome No difference between groups No difference between groups not primary outcome No difference between groups not primary outcome not primary outcome not primary outcome not primary outcome No difference between groups data not reported data not reported data not reported Intervention: a 1576 Control: a 594 Intervention: c 20 Control: c 6 Intervention :c 70% Control: c 20% Intervention: b 1400 Control: b 400 data not reported Intervention: :b 80% Control: b 25% Intervention: d 1250 Control: d 700 data not reported Intervention: d 90% Control: d 50% data not reported data not reported data not reported data not reported 9

Outcome Variables Mean protein delivery Mean grams/kg delivery b Estimated from Figure 4 8 c Estimated from Figure 2 6 d Estimated from Figure 2 9 e Estimated from supplement Figure 1 6 INTACT 4 Arabi 5 Singer 7 Casaer 6 Rice 8 Doig 9 Intervention: 82.2 ± 23.4 Control: 60.4 ± 23.7 Intervention: 43.6 ± 18.9 Control: 47.5 ± 21.2 Intervention: 76 ± 16 Control: 53 ± 16 data not reported data not reported data not reported Intervention: Intervention: 76.1 ± 17.7% 63.7 ± 25.0% Control: Control: 54.4 ± 20.7% 65.2 ± 25.7% a Provided in post-hoc analysis: Average calorie delivery among patients in the ICU for 7 study days (n=1262) 44 Mean percent protein delivery data not reported Intervention: e 0.6 Control: e 0.1 data not reported data not reported Intervention: d 48 Control: d 28 data not reported data not reported data not reported data not reported data not reported 10

hospital mortality of 40-50%. 39,43 Mean estimated energy needs in the intervention were 1767.6 (311.3) calories; (subjects received an average of 1252 ± 432) calories or 71.4 ± 22.8% of daily requirements. The control group had estimated energy needs of 1833.0 ± 335.8 calories per day and received an average 1066.6 ± 306 calories or 59.0 ± 16.1% of daily requirements (TABLE II). Both groups received an average of 0.6 grams of protein per kilogram. Hospital mortality was significantly higher in the intervention group (42.5% versus 30%, RR: 0.71 95% CI 0.50-0.99, p<0.05) compared to the control group. No difference was found in 28-day mortality, 180-day mortality, ICU mortality, hospital/icu length of stay, duration of mechanical ventilation and infectious complications between groups. 5 Singer et al. 7 observed negative outcomes with higher energy exposure in a single center PRCT. Patients were enrolled if they were expected to require mechanical ventilation for at least 72 hours. Subjects were randomized to receive EN or PN to meet energy requirements measured via indirect calorimetry until ICU discharge (intervention, n=65) or EN or PN delivered according to routine feeding protocols at 25 calories per pre-admit weight until ICU discharged (control, n=65). Indirect calorimetry was performed on both study groups every 48 hours while enrolled in the trial. Protein requirements were not established for study groups, protein delivery differed based on the rate and components of EN/PN provided. Mean age, weight and BMI were similar between groups (TABLE I). Average APACHE II and SOFA for both groups were approximately 22 and 6.5, respectively, indicating a hospital mortality of 30-40% for participants. 39,43 Mean measured energy needs in the intervention were 1976 ± 468 calories; subjects received an average of 2086 ± 460 calories, approximately 106% of daily requirements. The control group had measured energy needs of 1838 ± 468 calories per day and received 1480 ± 356 calories, approximately 81% of requirements (TABLE II). Protein delivery was different between groups. The intervention group received 76 ± 16 grams, nearly 1 gram per kilogram. The control group received 53 ± 16 grams or approximately 0.7 grams per kilogram. A trend toward lower hospital mortality in the intervention group (p=0.058) was found, 11

however, duration of mechanical ventilation (16.1 ± 14.7 versus 10.5 ± 8.3 days, p<0.05), ICU length of stay (17.2 ± 14.6 versus 11.7 ± 8.4 days, p<0.05) and total infection rate (28% versus 14%, p<0.05) were higher in the intervention versus control group. No difference was observed in ICU length of stay (TABLE II). 7 The EPaNIC PRCT conducted by Casaer et al. 6 enrolled patients from 7 ICUs to compare early versus late initiation of PN in the ICU. Patients admitted to the ICU with a Nutrition Risk Score 45 greater than three were enrolled. Subjects were randomized to the intervention group (n=2312), EN plus 20% dextrose solution for ICU days 1 and 2 with PN on ICU day 3 to supplement up to the calculated nutritional target until ICU discharge, or the control group (n=2328), EN plus 5% dextrose delivered in equal volume to the intervention group to provide adequate hydration with PN started after seven days if EN delivery remained below calculated nutritional target until ICU discharge. Calorie goals were estimated based on the equation provided in TABLE I. Protein requirements were not established for study groups. Gender and BMI distribution and mean age and weight were similar between groups. Only 40% of the sample required mechanical ventilation. Mean APACHE II was 23 in both groups, suggesting a predicted hospital mortality of 30-40%. 39 Average daily energy requirement and mean calorie delivery were not reported for each group; both percent delivery and calorie per kilogram were estimated from figures provided by the authors. Subjects within the intervention group received approximately 70% of requirements or 20 calories per kilogram and the control group received approximately 20% of requirements or 6 calories per kilogram. As seen in TABLE II, subjects in the intervention group received 0.6 grams protein per kilogram while the control group received 0.1 grams per kilogram. Subjects in the intervention group had more infectious complications (26% versus 23%, p=0.008), were more likely to require mechanical ventilation for more than two days (40% versus 36%, p=0.03) and had longer median ICU length of stay (4 (2-9) versus 3 (2-7) days, p=0.02). 6 12

After publication, a post-hoc analysis 44 of the EPaNIC trial was conducted to determine the influence of increasing calorie delivery (<30%, 30-50%, 50-70%, 70-90% and >90%) on time to discharge alive at ICU day 3, 5 and 7. The analysis revealed an inverse relationship between increasing calorie exposure and reduced likelihood for earlier discharge alive from the ICU at day 3 and 5 among patients randomized to the early PN group. A 1% increase in percentage of calorie delivery at day three and five was associated with an 8% (HR 0.992 95% CI 0.989-0.995, p<0.05) and 7% (HR 0.993 95% CI 0.989-0.997, p<0.05) decrease in likelihood of discharging from the ICU alive, respectively. A similar relationship was observed for calorie delivery in the entire population at ICU day 3. Exposure to the lowest calorie delivery intervals (<30% of needs) was associated with the fastest recovery. Rice et al. 8 reported no difference in outcomes between subjects who received trophic EN versus goal EN feeding for the first six days in the ICU. 8 Initially, a single-center pilot study was conducted among 200 ICU patients expected to require mechanical ventilation for 72 hours. 46 No difference in duration of mechanical ventilation, ICU/hospital length of stay or mortality was detected after randomizing patients to 10 ml/hour per day versus full-energy EN feeding for the first six days in the ICU. 46 Based on these findings a multi-center (44 ICUs) study was conducted; 1000 adults with ALI expected to require mechanical ventilation for at least 72 hours were randomized to 25 ml/hour (n=492) versus full-energy (n=508) EN for the first six days in the ICU. 8 Daily calorie and protein requirements were estimated at 25-30 calories per kilogram of non-protein calories and 1.2-1.6 grams of protein per ideal body weight. Mean age, weight and BMI and gender distribution were similar between groups (TABLE I). Based on APACHE III, anticipated hospital mortality for the study population was approximately 40%. 47 Average daily energy requirement and mean calorie delivery were not reported for each group; both percent delivery and calorie per kilogram were estimated from Figure 4 within the article. Subjects in the intervention group received approximately 1400 calories, representing 80% of estimated energy requirements. The control group received 400 calories, or 25% of 13

estimated energy requirements (TABLE II). Protein delivery was different between groups. The intervention group received approximately 54 grams of protein (0.6 grams per kilogram) and the control group received 11 grams of protein (0.1 grams per kilogram). Despite the divergence in calorie and protein delivery between groups, there was no difference in ventilator free days, ICU length of stay, infection, organ failure or mortality between groups (TABLE 1). 8 Doig et al. 9 conducted a multi-center (31 ICUs) PRCT comparing early PN versus standard care in 1372 subjects who were expected to stay in the ICU for 48 hours and unable to start EN. 9 Nutrition support was started in the intervention group (n=686) on study day one and target calories were achieved by study day three. Within the control group (n=686) determination of the route and timing of nutrition support therapy was left to the judgement of the ICU team. Estimated energy requirements were calculated with the Harris-Benedict equation using ideal body weight and stress factors; calorie goals were limited to 35 calories per kilogram. Protein requirements were estimated at 1.0-1.5 grams of protein per kilogram. Mean age and BMI were similar between groups; average weight was not reported. Mean APACHE II was 20.5 and 21.5 in the intervention and control group, anticipated hospital mortality for the study population was approximately 30-40%. 39 Average daily energy requirement and mean calorie delivery were not reported for each group; both percent delivery and calorie per kilogram were estimated from Figure 2 within the article. Subjects in the intervention group received approximately 1250 calories, representing 90% of estimated energy requirements. The control group received 700 calories or 50% of estimated energy requirements (TABLE 2). Protein delivery was different between groups. The intervention group received approximately 48 grams of protein per day versus 28 grams of protein per day in the control group. No difference in ICU length of stay, organ failure, infections or mortality occurred between groups; however, the intervention group had an improvement in 60-day quality of life (Research and Development-36 General Health Status: 49.8 versus 45.5). 9 14