Prognostic implications of the arginine metabolism in patients at nutritional risk: A secondary analysis of the randomized EFFORT trial

BACKGROUND

Arginine, a conditionally essential amino acid, is key component in metabolic pathways including immune regulation and protein synthesis. Depletion of arginine contributes to worse outcomes in severely ill and surgical patient populations. We assessed prognostic implications of arginine levels and its metabolites and ratios in polymorbid medical inpatients at nutritional risk regarding clinical outcomes and treatment response.

METHODS

Within this secondary analysis of the randomized controlled Effect of early nutritional support on Frailty, Functional Outcomes, and Recovery of malnourished medical inpatients Trial (EFFORT), we investigated the association of arginine, its metabolites and ratios (i.e., ADMA and SDMA, ratios of arginine/ADMA, arginine/ornithine, and global arginine bioavailability ratio) measured on hospital admission with short-term and long-term mortality by means of regression analysis.

RESULTS

Among the 231 patients with available measurements, low arginine levels ≤90.05 μmol/l (n = 86; 37 %) were associated with higher all-cause mortality at 30 days (primary endpoint, adjusted HR 3.27, 95 % CI 1.86 to 5.75, p < 0.001) and at 5 years (adjusted HR 1.50, 95 % CI 1.07 to 2.12, p = 0.020). Arginine metabolites and ratios were also associated with adverse outcome, but had lower prognostic value. There was, however, no evidence that treatment response was influenced by admission arginine levels.

CONCLUSION

This secondary analysis focusing on medical inpatients at nutritional risk confirms a strong association of low plasma arginine levels and worse clinical courses. The potential effects of arginine-enriched nutritional supplements should be investigated in this population of patients.

CLINICAL TRIAL REGISTRATION

clinicaltrials.gov as NCT02517476 (registered 7 August 2015).

ESPEN practical guideline: Nutritional support for polymorbid medical inpatients

BACKGROUND

Disease-related malnutrition in polymorbid medical inpatients is a highly prevalent syndrome associated with significantly increased morbidity, disability, short- and long-term mortality, impaired recovery from illness, and healthcare costs.

AIM

As there are uncertainties in applying disease-specific guidelines to patients with multiple conditions, our aim was to provide evidence-based recommendations on nutritional support for the polymorbid patient population hospitalized in medical wards.

METHODS

The 2023 update adheres to the standard operating procedures for ESPEN guidelines. We undertook a systematic literature search for 15 clinical questions in three different databases (Medline, Embase and the Cochrane Library), as well as in secondary sources (e.g., published guidelines), until July 12th, 2022. Retrieved abstracts were screened to identify relevant studies that were used to develop recommendations (including SIGN grading), which was followed by submission to Delphi voting. Here, the practical version of the guideline is presented which has been shortened and equipped with flow charts for patients care.

RESULTS

32 recommendations (7× A, 11× B, 10× O and 4× GPP), which encompass different aspects of nutritional support were included from the scientific guideline including indication, route of feeding, energy and protein requirements, micronutrient requirements, disease-specific nutrients, timing, monitoring and procedure of intervention. Here, the practical version of the guideline is presented which has been shortened and equipped with flow charts for patients care.

CONCLUSIONS

Recent high-quality trials have provided increasing evidence that nutritional support can reduce morbidity and other complications associated with malnutrition in polymorbid patients. The timely screening of patients for risk of malnutrition at hospital admission followed by individualized nutritional support interventions for at-risk patients should be part of routine clinical care and multimodal treatment in hospitals worldwide. Use of this updated practical guideline offers an evidence-based nutritional approach to polymorbid medical inpatients and may improve their outcomes.

Adaptation of nutritional risk screening tools may better predict response to nutritional treatment: a secondary analysis of the randomized controlled trial Effect of early nutritional therapy on Frailty, Functional Outcomes, and Recovery of malnourished medical inpatients Trial (EFFORT)

BACKGROUND

Nutritional screening tools have proven valuable for predicting clinical outcomes but have failed to determine which patients would be most likely to benefit from nourishment interventions. The Nutritional Risk Screening 2002 (NRS) and the Mini Nutritional Assessment (MNA) are 2 of these tools, which are based on both nutritional parameters and parameters reflecting disease severity.

OBJECTIVES

We hypothesized that the adaptation of nutritional risk scores, by removing parameters reflecting disease severity, would improve their predictive value regarding response to a nutritional intervention while providing similar prognostic information regarding mortality at short and long terms.

METHODS

We reanalyzed data of 2028 patients included in the Swiss-wide multicenter, randomized controlled trial EFFORT (Effect of early nutritional therapy on Frailty, Functional Outcomes, and Recovery of malnourished medical inpatients Trial) comparing individualized nutritional support with usual care nutrition in medical inpatients. The primary endpoint was 30-d all-cause mortality.

RESULTS

Although stratifying patients by high compared with low NRS score showed no difference in response to nutritional support, patients with high adapted NRS showed substantial benefit, whereas patients with low adapted NRS showed no survival benefit [adjusted hazard ratio: 0.55 [95% confidence interval (CI): 0.37, 0.80]] compared with 1.17 (95% CI: 0.70, 1.93), a finding that was significant in an interaction analysis [coefficient: 0.48 (95% CI: 0.25, 0.94), P = 0.031]. A similar effect regarding treatment response was found when stratifying patients on the basis of MNA compared with the adapted MNA. Regarding the prognostic performance, both original scores were slightly superior in predicting mortality than the adapted scores.

CONCLUSIONS

Adapting the NRS and MNA by including nutritional parameters only improves their ability to predict response to a nutrition intervention, but slightly reduces their overall prognostic performance. Scores dependent on disease severity may best be considered prognostic scores, whereas nutritional risk scores not including parameters reflecting disease severity may indeed improve a more personalized treatment approach for nourishment interventions. The trial was registered at clinicaltrials.gov as NCT02517476.

Association of tryptophan pathway metabolites with mortality and effectiveness of nutritional support among patients at nutritional risk: secondary analysis of a randomized clinical trial

Tryptophan is an essential amino acid and is the precursor of many important metabolites and neurotransmitters. In malnutrition, the availability of tryptophan is reduced, potentially putting patients at increased risks. Herein, we investigated the prognostic implications of the tryptophan metabolism in a secondary analysis of the Effect of Early Nutritional Support on Frailty, Functional Outcomes, and Recovery of Malnourished Medical Inpatients Trial (EFFORT), a randomized, controlled trial comparing individualized nutritional support to usual care in patients at risk for malnutrition. Among 238 patients with available measurements, low plasma levels of metabolites were independently associated with 30-day mortality with adjusted hazard ratios (HR) of 1.77 [95% CI 1.05-2.99, p 0.034] for tryptophan, 3.49 [95% CI 1.81-6.74, p < 0.001] for kynurenine and 2.51 [95% CI 1.37-4.63, p 0.003] for serotonin. Nutritional support had more beneficial effects on mortality in patients with high tryptophan compared to patients with low tryptophan levels (adjusted HR 0.61 [95% CI 0.29-1.29] vs. HR 1.72 [95% CI 0.79-3.70], p for interaction 0.047). These results suggest that sufficient circulating levels of tryptophan might be a metabolic prerequisite for the beneficial effect of nutritional interventions in this highly vulnerable patient population.

Red blood cell distribution width (RDW) - A new nutritional biomarker to assess nutritional risk and response to nutritional therapy?

BACKGROUND & AIMS

Red cell distribution width (RDW) has been proposed as a surrogate marker for acute and chronic diseases and may be influenced by nutritional deficits. We assessed the prognostic value of RDW regarding clinical outcomes and nutritional treatment response among medical inpatients at nutritional risk.

METHODS

This is a secondary analysis of EFFORT, a randomized, controlled, prospective, multicenter trial investigating the effects of nutritional support in patients at nutritional risk in eight Swiss hospitals. We examined the association between RDW and mortality in regression analysis.

RESULTS

Among 1,244 included patients (median age 75 years, 46.6 % female), high RDW (≥15 %) levels were found in 38 % of patients (n = 473) with a significant association of higher malnutrition risk [OR 1.48 (95%CI 1.1 to 1.98); p = 0.009]. Patients with high RDW had a more than doubling in short-term (30 days) mortality risk [adjusted HR 2.12 (95%CI 1.44 to 3.12); p < 0.001] and a signficant increase in long-term (5 years) mortality risk [adjusted HR 1.73 (95%CI 1.49 to 2.01); p < 0.001]. Among patients with high RDW, nutritional support reduced morality within 30 days [adjusted OR 0.56 (95%CI 0.33 to 0.96); p = 0.035], while the effect of the nutritional intervention in patients with low RDW was markedly smaller.

CONCLUSIONS

Among medical patients at nutritional risk, RDW correlated with several nutritional parameters and was a strong prognostic marker for adverse clinical outcomes at short- and long-term, respectively. Patients with high baseline RDW levels also showed a strong benefit from the nutritional intervention. Further research is needed to understand whether monitoring of RDW over time severs as a nutritional biomarker to assess effectiveness of nutritional treatment in the long run.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02517476.

Association of Glutamine and Glutamate Metabolism with Mortality among Patients at Nutritional Risk-A Secondary Analysis of the Randomized Clinical Trial EFFORT

Glutamine and its metabolite glutamate serve as the main energy substrates for immune cells, and their plasma levels drop during severe illness. Therefore, glutamine supplementation in the critical care setting has been advocated. However, little is known about glutamine metabolism in severely but not critically ill medical patients. We investigated the prognostic impact of glutamine metabolism in a secondary analysis of the Effect of Early Nutritional Support on Frailty, Functional Outcomes, and Recovery of Malnourished Medical Inpatients Trial (EFFORT), a randomized controlled trial comparing individualized nutritional support to usual care in patients at nutritional risk. Among 234 patients with available measurements, low plasma levels of glutamate were independently associated with 30-day mortality (adjusted HR 2.35 [95% CI 1.18-4.67, p = 0.015]). The impact on mortality remained consistent long-term for up to 5 years. No significant association was found for circulating glutamine levels and short- or long-term mortality. There was no association of glutamate nor glutamine with malnutrition parameters or with the effectiveness of nutritional support. This secondary analysis found glutamate to be independently prognostic among medical inpatients at nutritional risk but poorly associated with the effectiveness of nutritional support. In contrast to ICU studies, we found no association between glutamine and clinical outcome.

Inflammation and response to nutrition interventions

The complex interplay between nutrition and inflammation has become a major focus of research in recent years across different clinical settings and patient populations. Inflammation has been identified as a key driver for disease-related malnutrition promoting anorexia, reduced food intake, muscle loss, and on a cellular level, insulin resistance, which together stimulate catabolism. However, these effects may well be bidirectional, and there is strong evidence showing that nutrition influences inflammation. Several single nutrients and dietary patterns with either proinflammatory or anti-inflammatory properties have been studied, such as the long-chain ω-3 fatty acids eicosapentaenoic acid or docosahexaenoic acid. The Mediterranean diet combines several such nutrients and has been shown to improve medical outcomes in the outpatient setting. In addition, there is increasing evidence suggesting that inflammation affects the metabolism and modulates the response to nutrition support interventions. In fact, recent studies from the medical inpatient setting suggest that inflammation, mirrored by high levels of C-reactive protein, diminishes the positive effects of nutrition support. This may explain the lack of positive effects of some nutrition trials in severely ill patients, whereas similar approaches to nutritional support have shown positive results in less severely ill patients. The use of biomarkers, such as C-reactive protein, may help to identify patients with a lower response to nutrition, in whom other treatment options need to be used. There is need for additional research to understand how to best address the malnourished patient with inflammation by specifically lowering inflammation through anti-inflammatory medical treatments and/or nutrition interventions.

Association of admission cortisol levels with outcomes and treatment response in patients at nutritional risk : A secondary analysis of a randomized clinical trial

INTRODUCTION

Cortisol is a metabolically active stress hormone that may play a role in the pathogenesis of malnutrition. We studied the association between admission cortisol levels and nutritional parameters, disease severity, and response to nutritional support among medical inpatients at nutritional risk.

METHODS

Admission cortisol was measured in a subset of 764 patients participating in the Effect of Early Nutritional Support on Frailty, Functional Outcomes, and Recovery of Malnourished Medical Inpatients Trial (EFFORT), a multicentre, randomized-controlled trial that compared individualized nutritional support with usual nutritional care.

RESULTS

Overall, mean cortisol levels were 570 (± 293) nmol/L and significantly higher in patients with high nutritional risk (NRS ≥ 5) and in patients reporting loss of appetite. Cortisol levels in the highest quartile (> 723 nmol/l) were associated with adverse outcomes including mortality at 30 days and 5 years (adjusted HR 2.31, [95%CI 1.47 to 3.62], p = 0.001 and 1.51, [95%CI 1.23 to 1.87], p < 0.001). Nutritional treatment tended to be more effective regarding mortality reduction in patients with high vs. low cortisol levels (adjusted OR of nutritional support 0.54, [95%CI 0.24 to 1.24] vs. OR 1.11, [95%CI 0.6 to 2.04], p for interaction = 0.134). This effect was most pronounced in the subgroup of patients with severe malnutrition (NRS 2002 ≥ 5, p for interaction = 0.047).

CONCLUSION

This secondary analysis of a randomized nutritional trial suggests that cortisol levels are linked to nutritional and clinical outcome among multimorbid medical patients at nutritional risk and may help to improve risk assessment, as well as response to nutritional treatment.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02517476.

Changes in serum albumin concentrations over 7 days in medical inpatients with and without nutritional support. A secondary post-hoc analysis of a randomized clinical trial

BACKGROUND

Serum albumin concentrations are frequently used to monitor nutritional therapy in the hospital setting but supporting studies are largely lacking. Within this secondary analysis of a randomized nutritional trial (EFFORT), we assessed whether nutritional support affects short-term changes in serum albumin concentrations and whether an increase in albumin concentration has prognostic implications regarding clinical outcome and response to treatment.

METHODS

We analyzed patients with available serum albumin concentrations at baseline and day 7 included in EFFORT, a Swiss-wide multicenter randomized clinical trial that compared individualized nutritional therapy with usual hospital food (control group).

RESULTS

Albumin concentrations increased in 320 of 763 (41.9%) included patients (mean age 73.3 years (SD ± 12.9), 53.6% males) with no difference between patients receiving nutritional support and controls. Compared with patients that showed a decrease in albumin concentrations over 7 days, those with an increase had a lower 180-day mortality [74/320 (23.1%) vs. 158/443 (35.7%); adjusted odds ratio 0.63, 95% CI 0.44 to 0.90; p = 0.012] and a shorter length of hospital stay [11.2 ± 7.3 vs. 8.8 ± 5.6 days, adjusted difference -2.2 days (95%CI -3.1 to -1.2)]. Patients with and without a decrease over 7 days had a similar response to nutritional support.

CONCLUSION

Results from this secondary analysis indicate that nutritional support did not increase short-term concentrations of albumin over 7 days, and changes in albumin did not correlate with response to nutritional interventions. However, an increase in albumin concentrations possibly mirroring resolution of inflammation was associated with better clinical outcomes. Repeated in-hospital albumin measurements in the short-term is, thus, not indicated for monitoring of patients receiving nutritional support but provides prognostic information.

TRAIL REGISTRATION

ClinicalTrials.gov Identifier: NCT02517476.

ESPEN guideline on nutritional support for polymorbid medical inpatients

BACKGROUND

Disease-related malnutrition in polymorbid medical inpatients is a highly prevalent syndrome associated with significantly increased morbidity, disability, short- and long-term mortality, impaired recovery from illness, and cost of care.

AIM

As there are uncertainties in applying disease-specific guidelines to patients with multiple conditions, our aim was to provide evidence-based recommendations on nutritional support for the polymorbid patient population hospitalized in medical wards.

METHODS

This update adheres to the standard operating procedures for ESPEN guidelines. We did a systematic literature search for 15 clinical questions in three different databases (Medline, Embase and the Cochrane Library), as well as in secondary sources (e.g. published guidelines), until July 12th. Retrieved abstracts were screened to identify relevant studies that were used to develop recommendations (incl. SIGN grading), which was followed by submission to Delphi voting.

RESULTS

From a total of 3527 retrieved abstracts, 60 new relevant studies were analyzed and used to generate a guideline draft that proposed 32 recommendations (7x A, 11x B, 10x O and 4x GPP), which encompass different aspects of nutritional support including indication, route of feeding, energy and protein requirements, micronutrient requirements, disease-specific nutrients, timing, monitoring and procedure of intervention. The results of the first online voting showed a strong consensus (agreement of >90%) on 100% of the recommendations. Therefore, no final consensus conference was needed.

CONCLUSIONS

Recent high-quality trials have provided increasing evidence that nutritional support can reduce morbidity and other complications associated with malnutrition in polymorbid patients. The timely screening of patients for risk of malnutrition at hospital admission followed by individualized nutritional support interventions for at-risk patients should be part of routine clinical care and multimodal treatment in hospitals worldwide. Use of this updated guideline offers an evidence-based nutritional approach to the polymorbid medical inpatients and may improve their outcomes.