Serum-albumin as a prognostic indicator in oedematous malnutrition

Micronutrients and nutritional status among children living with HIV with and without severe acute malnutrition: IMPAACT P1092

BACKGROUND

Micronutrient deficiencies from malabsorption, gut infections, and altered gut barrier function are common in children living with the human immunodeficiency virus (CLHIV) and may worsen with severe acute malnutrition (SAM). Exploratory data of baseline zinc and selenium levels and changes over 48 weeks in children living with HIV by nutritional status are presented.

METHODS

Zinc, selenium, serum protein and albumin levels measured at study entry and over 48 weeks were compared between children aged 6 to < 36 months who were living with HIV and had SAM or mild malnutrition-normal nutrition. Children with SAM were enrolled after 10-18 days of nutritional rehabilitation. Two-sided t-tests were used to compare levels and changes in levels of micronutrients and proteins by nutritional status.

RESULTS

Fifty-two participants, 25 with and 27 without SAM, of median (Q1,Q3) age 19 (13,25) and 18 (12,25) months respectively, were enrolled. Zinc deficiency was present at entry in 2/25 (8%) of those who had SAM. Mean (SD) baseline zinc levels were [52.2(15.3) and 54.7(12.0) µg/dL] for the SAM and non-SAM cohorts respectively while selenium levels were similar [92.9(25.0), 84.3(29.2) µg/L]. Mean changes of zinc and selenium from study entry to week 48 were similar between the children with and without SAM. There was no significant difference between baseline protein levels [75.2(13.2), 77.3(9.4) g/L] and the mean change from study entry to 48 weeks was also similar between the two groups; with a mean difference of 4.6 g/L [95% CI, (-2.4,11.6)]. Children with SAM compared to those without had significantly lower serum albumin levels at study entry with similar levels at 48 weeks.

CONCLUSIONS

Children with severe malnutrition who were initiated/switched to zidovudine/lamivudine/boosted lopinavir following 10 to 18 days of nutritional rehabilitation showed normal baseline levels of selenium and zinc, and had comparable selenium levels after 48 weeks. There was a strong positive correlation in entry and week 48 selenium levels within each cohort and for zinc in the non-SAM cohort. These data support the current WHO recommended approach to management of severe malnutrition in CLHIV who are initiated on combination antiretroviral treatment.

TRIAL REGISTRATION

Registered with ClinicalTrials.gov Identifier NCT01818258 26/03/2013.

Oedema in kwashiorkor is caused by hypoalbuminaemia

It has been argued that the oedema of kwashiorkor is not caused by hypoalbuminaemia because the oedema disappears with dietary treatment before the plasma albumin concentration rises. Reanalysis of this evidence and a review of the literature demonstrates that this was a mistaken conclusion and that the oedema is linked to hypoalbuminaemia. This misconception has influenced the recommendations for treating children with severe acute malnutrition. There are close pathophysiological parallels between kwashiorkor and Finnish congenital nephrotic syndrome (CNS) pre-nephrectomy; both develop protein-energy malnutrition and hypoalbuminaemia, which predisposes them to intravascular hypovolaemia with consequent sodium and water retention, and makes them highly vulnerable to develop hypovolaemic shock with diarrhoea. In CNS this is successfully treated with intravenous albumin boluses. By contrast, the WHO advise the cautious administration of hypotonic intravenous fluids in kwashiorkor with shock, which has about a 50% mortality. It is time to trial intravenous bolus albumin for the treatment of children with kwashiorkor and shock.

Severe malnutrition is associated with decreased levels of plasma transferrin receptor

Sixty children aged 1-3 years with protein malnutrition were involved in the present study. Measurements were made of plasma transferrin receptor (TfR), haemoglobin (Hb), ferritin, transferrin and Fe in comparison with twenty apparently healthy age- and sex-matched reference children in Nigeria. Plasma TfR was measured by an immunofluorometric assay. The mean plasma concentrations of both albumin (37 g/l) and transferrin (1·88 g/l) were within reference ranges in the ‘healthy’ children. The malnourished children had severe protein deficiency as indicated by their significantly lower mean plasma albumin (24·4-28·2 g/l; P < 0·0001) and transferrin (1·24-1·53 g/l; P < 0·0001) concentrations in comparison with the reference children. In the reference children, the traditional indicators of Fe nutrition (plasma Fe, transferrin Fe saturation and Hb) were within the reference ranges, but ferritin values were raised, indicating acute or chronic infection and/or inflammation. The mean concentrations of plasma TW (4·2-5-2 mg/l) in the malnourished group were significantly lower than the mean (6·1 mgn) of the reference children (P=0·0009). In the children with severe malnutrition, none of the indicators of Fe status except Hb (81·5-86·7 g/l; P<0·0001) showed Fe deficiency, including the serum concentration of TfR and the TfR : ferritin ratio, although the Fe status was lower than in the reference children (for Fe P = 0·009; and ferritin P=0·0004). In the absence of haemodilution, the low Hb values are a clear indication that the malnourished children were Fe deficient; none of the other indices was indicative of Fe deficiency. This is the first report of TfR levels in malnourished and healthy African children.

Laboratory support of the clinical nutrition service

This article critically reviews the role of the laboratory services in assessment, monitoring and management of complications in patients requiring nutritional support. It has broadly been divided into three sections. (i) Assessment of protein and energy status: whilst it is stressed that clinical judgement and anthropometric measurements are the most effective methods of evaluation of nutritional requirements, laboratory tests which can be of use in assessment of protein energy status are discussed in detail, including an appraisal of the value of each test in various clinical situations. (ii) Assessment of micronutrient and electrolyte status: the clinical justification for assessment of the various micronutrients and electrolytes is considered. A few selected examples are discussed in detail including an evaluation of the tests of status available and examples of situations where measurement may be clinically helpful. (iii) Effective use of the laboratory: this section attempts to guide the clinician in the most appropriate use of laboratory tests, firstly in the assessment of requirement for aspects of nutritional support, secondly in the continued monitoring and evaluation of the support provided, and thirdly in prevention and treatment of metabolic complications. It is emphasised that clinical nutrition is a multidisciplinary topic requiring input from the laboratory in conjunction with other specialities to provide the best available patient care.

Development and validation of the Burton Score: a tool for nutritional assessment

This paper describes the development and validation of the Burton Score, a nutritional assessment tool based on the Waterlow score, with the rationale that since nurses already collect data for one score, it would only lead to unnecessary duplication of effort if a totally different scoring scheme were to be used for nutritional assessment. Initial cut offs were determined by a pilot study of 26 patients on an elderly care ward and validated by comparing the nutritional status of 263 patients estimated by the Burton score with a dietitian's assessment of nutrition. The validation study showed that although there was significant correlation between the Burton and Waterlow scores the Burton score correlated more closely with the dietitian's assessments. The King's Fund report of 1992 stated that all patients should have assessment of nutritional status on admission to hospital: we believe the Burton score could provide a simple tool to achieve this goal.

Assessment of plasma fibronectin in malnourished Nigerian children

BACKGROUND

Severe malnutrition is associated with septic infections. The concentrations of fibronectin, albumin, and transferrin in plasma were measured in three groups of children with protein-energy malnutrition, aged 1-3 years, each group comprising 20 children. The aim of which was to test whether plasma fibronectin, being an opsonic protein, was reduced in such children, and if it was a useful index for assessing the severity of malnutrition.

METHODS

The concentrations of fibronectin, albumin, and transferrin in plasma were studied by enzyme immunoassay/ immunoblotting, spectrophotometry and immunoturbidimetry respectively.

RESULTS

All values were significantly lower in the patients with malnutrition than in the age- and sex-matched well-nourished Nigerian reference children. Within the malnourished group, the fibronectin value was evenly reduced in all subgroups. Albumin and transferrin values were lowest in the patients with kwashiorkor, highest in the marasmic patients, and intermediate in the patients with marasmic kwashiorkor; the values correlated mutually in individual cases as well, but not with the fibronectin levels. Neither plasma fibronectin fragmentation nor tissue fibronectin was detected in any patient with malnutrition or in the reference subjects.

CONCLUSIONS

The reduced plasma fibronectin values in these patients may be due to reduced synthesis by the liver, as evidenced by the equally reduced albumin and transferrin concentrations and/or to the multiple infections characteristic of the patients.

International Federation of Clinical Chemistry. Laboratory assessment of protein-energy status

Laboratory and non-laboratory methods for assessing protein-energy nutritional status are reviewed. These are classified into methods for assessing adequacy of recent nutritional intake, methods for assessing whole body status, and tests which assist in the interpretation of these assessments. Each measurement is critically discussed in terms of the rationale for its use, the method of analysis, reference values, technical interference and limitations of methods, the effects of nutritional status and of other factors on the results, its overall usefulness in nutritional assessment, and its value relative to other methods. Non-laboratory tests such as dietary assessment, indirect calorimetry, functional tests and the many methods available for assessment of body composition, including anthropometry, bioelectrical impedance and isotope and imaging techniques, are compared with the clinical chemistry tests in common use, such as nitrogen balance, plasma protein measurements and urinary markers of muscle metabolism. This review provides comprehensive and practical advice on the use and limitations of these tests in the assessment of protein-energy nutritional status of a group, or of an individual patient.

Serum albumin concentration, arm circumference, and oedema and subsequent risk of dying in children in central Africa

OBJECTIVE

To measure the prognostic value of clinical, anthropometric, and biological indicators of protein energy malnutrition in hospitalised children.

DESIGN

Hospital based follow up study from admission to discharge or death of a cohort of children. SETTING-Paediatric hospital in Zaire.

SUBJECTS

1129 children consecutively admitted between August 1986 and October 1988.

MAIN OUTCOME MEASURES

Height, weight, arm circumference, skinfold thicknesses, serum albumin concentration, and mortality.

RESULTS

Mortality was higher in wasted children and in those with a mid-upper arm circumference < 125 mm, a serum albumin concentration < 16 g/l, and oedema. After multivariate analysis, serum albumin concentration was the best predictor of subsequent risk of dying. Mid-upper arm circumference and oedema, however, still contributed considerably to evaluation of mortality.

CONCLUSIONS

In this specific environment of central Africa an isolated clinical sign such as oedema is not enough to detect children with a high risk of dying among those admitted to paediatric wards with severe protein energy malnutrition. Measurement of additional indicators such as arm circumference and serum albumin concentration seems to be of crucial importance.

Whole-body albumin mass and distribution in rats fed on low-protein diets

1. From 5 weeks of age, control and experimental rats were given diets containing 210 and 31 g protein/kg respectively, and killed for analysis at 0, 2, 5, 8, 12 and 20 d after the start of the experiment. At these times estimates were made of plasma albumin concentration, plasma volume and total vascular and extravascular albumin mass. 2. Plasma albumin concentrations were significantly lower in the experimental animals when compared to controls at 8, 12 and 20 d but plasma volumes (ml/kg body-weight) tended to be greater in the former animals. Total vascular albumin mass (g/kg body-weight) was significantly less in experimental animals compared to controls at 8 and 20 d, but was significantly reduced below values at 0 d only at 20 d. 3. extravascular albumin mass (g/kg body-weight) was significantly lower in experimental animals in comparison with controls at 2, 5, 8, 12 and 20 d and significantly reduced below values at 0 d at 5, 8, 12, and 20 d. 4. Whole-body albumin mass was significantly reduced at 5, 8, 12 and 20 d when compared both with controls killed at the same time and animals killed at 0 d. Measurement of the ratio, extravascular albumin mass: vascular albumin mass indicated a significant redistribution of whole-body albumin mass at 5 and 20 d and mean values for this ratio were always lower in experimental animals than in controls. 5. It was concluded that measurement of plasma albumin concentration does not indicate the true extent of whole-body albumin losses in protein deficiency since total vascular albumin mass is, to some extent, maintained at the expense of extravascular albumin mass.