This Month in AJKD

Article Outline

• Obesity and CKD
• Self-Reported Health and Mortality
• Mutations in Factor H in aHUS
• A Review of Drug-Induced Hyponatremia

Back to Article Outline

Obesity and CKD 

See Ritz, pages 1-6. See also pages 29-73.

Obesity is a risk factor for incident diabetes as well as cardiovascular events; however, the relationship between obesity and both subsequent kidney disease as well as cardiovascular outcomes in individuals with kidney disease is less certain, particularly given the distinct survival advantage among dialysis patients with a higher body mass index. This month in AJKD, a series of manuscripts assesses obesity in kidney disease, highlighting the diagnosis of obesity as well as the interplay among obesity, kidney disease, and outcomes. An editorial by Dr Ritz introduces this topic with 2 important observations: not all body fat is created equal with visceral fat conferring a substantially greater cardiovascular risk than subcutaneous fat, and both albuminuria and decreased GFR are manifestations of CKD that may be due to obesity. Among the 5 obesity-related articles in this issue of AJKD are a report from the Framingham Heart Study showing a 68% increased odds of developing CKD stage 3 among obese individuals, which was attenuated after multivariable adjustment as well as an 56% increased risk of incident dipstick proteinuria among obese individuals in adjusted models; reports from the Atherosclerosis Risk in Communities Study and the Cardiovascular Health Study demonstrating a significant relationship between waist-to-hip ratio but not body mass index and incident CKD in a generalizable US cohort as well as a significant relationship between waist-to-hip ratio but not body mass index and subsequent cardiovascular events and death among individuals with stage 3-4 CKD; a report from Sao Paolo, Brazil demonstrating better agreement between visceral fat and waist circumference than body mass index in a diverse CKD population; and a report from Nanjing, China reviewing 90 cases of obesity-related glomerulopathy on kidney biopsy between 2002 and 2006.

• 
  • View Large Image
  • Download to PowerPoint

• Figure reproduced with permission from David Gregory & Debbie Marshall/Wellcome Images. Available at: http://images.wellcome.ac.uk. Last accessed: May 15, 2008

Back to Article Outline

Self-Reported Health and Mortality 

See Cavanaugh et al, pages 118-127 and Thong et al, pages 111-117.

“The patient knows best” is a slogan that has gained increasing acceptance in modern medicine. Included this month are 2 large prospective cohort studies that explore this statement in dialysis patients. In data from the CHOICE Study, Cavanaugh et al report a higher risk of mortality among patients who inaccurately report their heart disease history. In data from 1,443 participants in the Netherlands Cooperative Study on the Adequacy of Dialysis (NECOSAD 2), Thong et al report that a patient's response to the simple question: “How would you say your health is in general?” is a strong, graded, independent predictor of mortality.

• 
  • View Large Image
  • Download to PowerPoint

Back to Article Outline

Mutations in Factor H in aHUS 

See Aberrategui-Garrido et al, pages 171-180.

Nearly half of all patients with atypical hemolytic uremic syndrome (aHUS) have mutations in the compliment proteins factor H, factor I, factor B, or C3, or in membrane cofactor protein. The prognosis in patients with these mutations, specifically a factor H mutation, is poor, and kidney transplant often fails in these individuals due to recurrent aHUS affecting the graft. Current therapy for aHUS requires rapid recognition of this disease; accordingly, most genetic studies are too time-consuming to guide initial therapy. In this month's In Translation feature, Abarrategui-Garrido et al describe a case of aHUS where an in vitro factor H-dependent hemolytic assay detected anomalous regulation of the alternative pathway, suggesting dysfunction of factor H; this was later confirmed with genetic testing. The authors then review recent advances in understanding molecular mechanisms contributing to aHUS and the benefits of functional analyses of factor H activity to guide treatment in aHUS patients.

• 
  • View Large Image
  • Download to PowerPoint

Back to Article Outline

A Review of Drug-Induced Hyponatremia 

See Liamis et al, pages 144-153.

Hyponatremia is the most common electrolyte disturbance in clinical practice and is associated with considerable morbidity and mortality. Many drugs are commonly associated with hyponatremia, including thiazide diuretics, antidepressants, and antiepilectics; notably, other newer agents have also been associated with hyponatremia, including antibiotics, proton pump inhibitors, and IVIg. In this issue, Liamis et al review the epidemiology and pathophysiology of drug-induced hyponatremia.

• 
  • View Large Image
  • Download to PowerPoint

• Image reproduced with permission from Pham PC, Pham PM, Pham PT: Vasopressin excess and hyponatremia. Am J Kidney Dis 47:727-737, 2007