Prediction of nutritional status by chemical analysis of urine and anthropometric methods

Urinary Organic Acids Increase After Clinical Stabilization of Hospitalized Children With Severe Acute Malnutrition

BACKGROUND

Despite a reduction of child mortality in low-income countries, acutely ill undernourished children still have an elevated risk of death. Those at highest risk are children with severe acute malnutrition (SAM) who often show metabolic dysregulation that remains poorly understood.

OBJECTIVE

We performed a pilot study to examine changes in urinary organic acids during nutritional rehabilitation of children with SAM, and to identify metabolites associated with the presence of edema or with mortality.

METHODS

This study included 76 children aged between 6 and 60 months, hospitalized for SAM at the Moyo Nutritional Rehabilitation and Research Unit in Blantyre, Malawi. Urine was collected at admission and 3 days after clinical stabilization and metabolomics were performed using gas chromatography-mass spectrometry. Metabolite concentrations were evaluated with both uni- and multivariate approaches.

RESULTS

Most metabolites increased 3 days after clinical stabilization, and total urinary concentration changed from 1.2 mM (interquartile range [IQR], 0.78-1.7) at admission to 3.8 mM (IQR, 2.1-6.6) after stabilization (P < .0001). In particular, 6 metabolites showed increases: 3-hydroxybutyric, 4-hydroxyhippuric, p-hydroxyphenylacetic, oxoglutaric, succinic, and lactic acids. Urinary creatinine was low at both time points, but levels did increase from 0.63 mM (IQR, 0.2-1.2) to 2.6 mM (IQR,1.6-4.4; P < .0001). No differences in urinary profiles were found between children who died versus those who survived, nor between children with severe wasting or edematous SAM.

CONCLUSIONS

Total urinary metabolites and creatinine increase after stabilization and may reflect partial recovery of overall metabolism linked to refeeding. The use of urinary metabolites for risk assessment should be furthered explored.

TRIAL REGISTRATION

TranSAM study (ISRCTN13916953).

Urine collection pads: are samples reliable for urine biochemistry and microscopy?

The aim of the study was to validate the reliability of samples obtained with urine collection pads (UCP) for selected laboratory biochemical analyses, urine cell microscopy, and bedside semi-quantitative stick urinalysis. A series of laboratory experiments was performed to test agreement between urine concentrations, or results, before and after passage through a UCP (incubated for 37 degrees C for 15 min). The following urinalyses were performed: electrolytes, calcium, phosphate, urate, osmolality, pH, protein, catecholamines, toxicology for drugs of abuse, stick urinalysis for glucose, ketones, protein, blood, leucocytes and nitrites, and microscopy for red and white cells. Close agreement was shown for all laboratory analyses except proteinuria, which was underestimated by, on average, 10% after UCP passage. However, stick urinalysis for proteinuria remains sufficiently reliable for clinical use. UCP substantially retain or destroy red and white cells, but stick urinalysis for blood and leucocyte esterase remains reliable. In conclusion, urine samples derived from UCP show good agreement across a clinically relevant range for the biochemical analyses undertaken in this study. Microscopy of UCP samples is unreliable for cellular material but semi-quantitative stick urinalysis for red and white cells is a satisfactory alternative.