Prognostic capability of the Maximum Acute Gastrointestinal Injury Score and of caloric intake in patients requiring vasopressors: A multicenter prospective cohort study

PURPOSE

Our main objective was to use the Maximum Acute Gastrointestinal Injury Score (AGI_max) to evaluate the prognostic capability of gastrointestinal dysfunction (GID), on hospital mortality in patients on mechanical ventilation (MV) requiring vasopressors. A secondary goal was to analyze the relationship between AGI_max and vasopressor dosage with increasing caloric intake.

MATERIALS AND METHODS

Prospective multicenter cohort study in ten ICUs across Argentina. Consecutive adult patients on MV, requiring vasopressors and receiving enteral nutrition (EN) were included. AGI_max was identified (I-IV) using a modified AGI score. Comparisons of clinical and outcome variables were performed in 3 predetermined EN-groups: <10 kcal/kg/d, ≥10 to <20 kcal/kg/d, or ≥ 20 kcal/kg/d.

RESULTS

A total of 494 patients met all inclusion criteria. Forty-four percent of patients had severe AGI_max and 17% received <10 kcal/kg/day, indicating more severity and higher mortality. Notable independent predictors of mortality were AGI_max, vasopressors, and caloric intake. PN was the only factor which had an inverse relationship to mortality.

CONCLUSIONS

In this population, patients with AGI_max III-IV were significantly associated with lower caloric intake and greater hospital mortality, highlighting the importance of AGI as a prognostic tool. As PN was linked with lower mortality, it could be an option to explore in further studies.

Prescribed hypocaloric nutrition support for critically-ill adults

BACKGROUND

There are controversies about the amount of calories and the type of nutritional support that should be given to critically-ill people. Several authors advocate the potential benefits of hypocaloric nutrition support, but the evidence is inconclusive.

OBJECTIVES

To assess the effects of prescribed hypocaloric nutrition support in comparison with standard nutrition support for critically-ill adults SEARCH METHODS: We searched the Cochrane Central Register of Controlled Trials (CENTRAL, Cochrane Library), MEDLINE, Embase and LILACS (from inception to 20 June 2017) with a specific strategy for each database. We also assessed three websites, conference proceedings and reference lists, and contacted leaders in the field and the pharmaceutical industry for undetected/unpublished studies. There was no restriction by date, language or publication status.

SELECTION CRITERIA

We included randomized and quasi-randomized controlled trials comparing hypocaloric nutrition support to normo- or hypercaloric nutrition support or no nutrition support (e.g. fasting) in adults hospitalized in intensive care units (ICUs).

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane. We meta-analysed data for comparisons in which clinical heterogeneity was low. We conducted prespecified subgroup and sensitivity analyses, and post hoc analyses, including meta-regression. Our primary outcomes were: mortality (death occurred during the ICU and hospital stay, or 28- to 30-day all-cause mortality); length of stay (days stayed in the ICU and in the hospital); and Infectious complications. Secondary outcomes included: length of mechanical ventilation. We assessed the quality of evidence with GRADE.

MAIN RESULTS

We identified 15 trials, with a total of 3129 ICU participants from university-associated hospitals in the USA, Colombia, Saudi Arabia, Canada, Greece, Germany and Iran. There are two ongoing studies. Participants suffered from medical and surgical conditions, with a variety of inclusion criteria. Four studies used parenteral nutrition and nine studies used only enteral nutrition; it was unclear whether the remaining two used parenteral nutrition. Most of them could not achieve the proposed caloric targets, resulting in small differences in the administered calories between intervention and control groups. Most studies were funded by the US government or non-governmental associations, but three studies received funding from industry. Five studies did not specify their funding sources.The included studies suffered from important clinical and statistical heterogeneity. This heterogeneity did not allow us to report pooled estimates of the primary and secondary outcomes, so we have described them narratively.When comparing hypocaloric nutrition support with a control nutrition support, for hospital mortality (9 studies, 1775 participants), the risk ratios ranged from 0.23 to 5.54; for ICU mortality (4 studies, 1291 participants) the risk ratios ranged from 0.81 to 5.54, and for mortality at 30 days (7 studies, 2611 participants) the risk ratios ranged from 0.79 to 3.00. Most of these estimates included the null value. The quality of the evidence was very low due to unclear or high risk of bias, inconsistency and imprecision.Participants who received hypocaloric nutrition support compared to control nutrition support had a range of mean hospital lengths of stay of 15.70 days lower to 10.70 days higher (10 studies, 1677 participants), a range of mean ICU lengths of stay 11.00 days lower to 5.40 days higher (11 studies, 2942 participants) and a range of mean lengths of mechanical ventilation of 13.20 days lower to 8.36 days higher (12 studies, 3000 participants). The quality of the evidence for this outcome was very low due to unclear or high risk of bias in most studies, inconsistency and imprecision.The risk ratios for infectious complications (10 studies, 2804 participants) of each individual study ranged from 0.54 to 2.54. The quality of the evidence for this outcome was very low due to unclear or high risk of bias, inconsistency and imprecisionWe were not able to explain the causes of the observed heterogeneity using subgroup and sensitivity analyses or meta-regression.

AUTHORS' CONCLUSIONS

The included studies had substantial clinical heterogeneity. We found very low-quality evidence about the effects of prescribed hypocaloric nutrition support on mortality in hospital, in the ICU and at 30 days, as well as in length of hospital and ICU stay, infectious complications and the length of mechanical ventilation. For these outcomes there is uncertainty about the effects of prescribed hypocaloric nutrition, since the range of estimates includes both appreciable benefits and harms.Given these limitations, results must be interpreted with caution in the clinical field, considering the unclear balance of the risks and harms of this intervention. Future research addressing the clinical heterogeneity of participants and interventions, study limitations and sample size could clarify the effects of this intervention.

HIV Lipodystrophy Case Definition using Artificial Neural Network Modelling

Objective

A case definition of HIV lipodystrophy has recently been developed from a combination of clinical, metabolic and imaging/body composition variables using logistic regression methods. We aimed to evaluate whether artificial neural networks could improve the diagnostic accuracy.

Methods

The database of the case-control Lipodystrophy Case Definition Study was split into 504 subjects (265 with and 239 without lipodystrophy) used for training and 284 independent subjects (152 with and 132 without lipodystrophy) used for validation. Back-propagation neural networks with one or two middle layers were trained and validated. Results were compared against logistic regression models using the same information.

Results

Neural networks using clinical variables only (41 items) achieved consistently superior performance than logistic regression in terms of specificity, overall accuracy and area under the ROC curve. Their average sensitivity and specificity were 72.4 and 71.2%, as compared with 73.0 and 62.9% for logistic regression, respectively (area under the ROC curve, 0.784 vs 0.748). The discriminating performance of the neural networks was largely unaffected when built excluding 13 parameters that patients may not have readily available. The average sensitivity and specificity of the neural networks remained the same when metabolic variables were also considered (total 60 items) without a clear advantage against logistic regression (overall accuracy 71.8%). The performance of networks considering also body composition variables was similar to that of logistic regression (overall accuracy 78.5% for both).

Conclusions

Neural networks may offer a means to improve the discriminating performance for HIV lipodystrophy, when only clinical data are available and a rapid approximate diagnostic decision is needed. In this context, information on metabolic parameters is apparently not helpful in improving the diagnosis of HIV lipodystrophy, unless imaging and body composition studies are also obtained.

Agreement analysis of variables involved in lipodystrophy syndrome definition in HIV-infected patients

BACKGROUND

Lipodystrophy studies in HIV-infected patients have usually defined abnormalities in body fat by clinical evaluation and patient questionnaires. Despite the risk for bias with these subjective approaches, agreement analysis among the large number of variables employed was seldom performed.

OBJECTIVE

To analyze consistency between the usual approaches for definition of abnormalities in body fat distribution.

DESIGN

We evaluated agreement between the clinical and questionnaire findings for abnormalities in body fat in an HIV patient population under antiretroviral treatment followed in our institution, using different criteria for definitions of body fat abnormalities within the same data set.

METHODS

Kappa analysis for consistency and receiver-operator characteristic (ROC) curve analysis were performed.

RESULTS

Low levels of agreement between clinical and patient perspectives were observed. Only one combination of criteria showed adequate agreement results. The waist/hip ratio showed low levels of agreement with all other variables, and no clear discriminative point was observed by ROC curve analysis. The ratio between the trunk fat content and the leg fat content assessed by dual energy x-ray absorptiometry (DEXA) scan demonstrated better agreement and more clear discriminative values for both male and female patients.

CONCLUSION

Agreement analyses may help in the selection of the subjective variable methodology and in the inclusion of consistent and nonredundant objective measurements for diagnosis of abnormalities in body fat.