Evaluation of different bioimpedance methods for assessing body composition in Asian non-dialysis chronic kidney disease patients

BACKGROUND: Chronic kidney disease (CKD) is associated with fluid retention, which increases total body water (TBW) and leads to changes in intracellular water (ICW) and extracellular water (ECW). This complicates accurate assessments of body composition. Analysis of bioelectrical impedance may improve the accuracy of evaluation in CKD patients and multiple machines and technologies are available. We compared body composition by bioimpedance spectroscopy (BIS) against multi-frequency bioimpedance analysis (BIA) in a multi-ethnic Asian population of stable, non-dialysis CKD patients. METHODS: We recruited 98 stable CKD patients comprising 54.1% men and 70.4% Chinese, 9.2% Malay, 13.3% Indian, and 8.2% other ethnicities. Stability was defined as no variation in serum creatinine > 20% over three months. Patients underwent BIS analyses using a Fresenius body composition monitor, while BIA analyses employed a Bodystat Quadscan 4000. RESULTS: Mean TBW values by BIS and BIA were 33.6 ± 7.2 L and 38.3 ± 7.4 L; mean ECW values were 15.8 ± 3.2 L and 16.9 ± 2.7 L; and mean ICW values were 17.9 ± 4.3 L and 21.0 ± 4.9 L, respectively. Mean differences for TBW were 4.6 ± 1.9 L (P < 0.001), for ECW they were 1.2 ± 0.5 L (P < 0.001), and for ICW they were 3.2 ±1.8 L (P < 0.001). BIA and BIS measurements were highly correlated: TBW r = 0.970, ECW r = 0.994, and ICW r = 0.926. Compared with BIA, BIS assessments of fluid overload appeared to be more associated with biochemical and clinical indicators. CONCLUSION: Although both BIA and BIS can be used for body water assessment, clinicians should be aware of biases that exist between bioimpedance techniques. The values of body water assessments in our study were higher in BIA than in BIS. Ethnicity, sex, body mass index, and estimated glomerular filtration rate were associated with these biases.

Genomics and disease progression in IgA nephritis

Apart from clinical, histological and biochemical indices, genomics are now being employed to unravel the pathogenetic mechanisms in the disease progression of IgA nephritis (IgAN). The results of angiotensin converting enzyme (ACE) gene polymorphism have been controversial. Those patients with the DD genotype seem to have a poorer prognosis. However, with high dose angiotensin receptor blocker (ARB) therapy, the ACE gene polymorphism status of a patient may no longer be a matter for concern as those with the DD genotype would also respond favourably to high dose ARB therapy. Association studies with gene sequencing and haplotypes have suggested that multiple genes are involved in the pathogenesis of IgAN. Some workers have reported a synergistic effect in the combined analysis of AGT-M235T and ACE I/D polymorphism. With the use of deoxyribo nucleic acid (DNA) microarray, tens of thousands of gene expressions genome-wide can be examined together simultaneously. A locus of familial IgAN has been described with strong evidence of linkage to IgAN1 on chromosome 6q22-23. Two other loci were reported at 4q26-31 and 17q12-22. DNA microarray techniques could also help in the identification of specific pathogenic genes that are up- or down-regulated and this may allow genome wide analyses of these genes and their role in the pathogenesis and progression of IgAN. Recently, using genome-wide association studies (GWAS) more loci for disease susceptibility for IgAN have been identified at 17p13, 8p23, 22q12, 1q32 and 6p21.

National Health Survey on the prevalence of urinary abnormalities in the population: then and now (1975 to 2012)

<p><b>INTRODUCTION</b>This paper presents the results of a community survey on urinary abnormalities which covered 1/80th of the population of Singapore in 1975. These findings were compared with the data from the Singapore National Service Registrants in 1974 as well as data from a recent survey in Singapore and that of other Asian and Western countries.</p><p><b>MATERIALS AND METHODS</b>The study covered 18,000 persons aged 15 years and above, representing a sampling fraction of 1/80th of the population. A total of 16,808 respondents attended the field examination centres, of whom 16,497 had their urine sample tested representing 92.7% of the sample population.</p><p><b>RESULTS</b>In the dipstick urine testing at the field examination centres, 769 subjects (4.6%) were found to have urinary abnormalities. Two hundred and eighty-two (36.7%) of these 769 subjects were found to have urinary abnormalities based on urine microscopy constituting a prevalence of 1.71%. The prevalence of proteinuria was 0.63% and for both haematuria and proteinuria was 0.73%. The prevalence for hypertension was 0.43% and renal insufficiency was 0.1%.</p><p><b>DISCUSSION</b>The consensus is that routine screening for chronic kidney disease (CKD) in the general population is not cost effective as the yield is too low. Whilst, most studies showed that screening of the general population was not cost effective, it has been suggested that screening for targeted groups of subjects could help to identify certain risk groups who may benefit from early intervention to prevent or retard the progression of CKD.</p><p><b>CONCLUSION</b>The prevalence of urinary abnormalities in Singapore has remained the same, now and three decades ago.</p>