Interview with
Jeffrey H. Burbank
Founder& CEO of NxStage

Hemodialysis.com: What are the main findings of the study?

AN and eating disorders are frequent and affect a young population.

Kidney diseases are very frequent and various in these patients: CKD, AKI, lithiasis and electrolytes disturbance.

However, all these kidney injuries are underestimated. 

Hemodialysis.com: Were any of the findings unexpected?

When we did the literature review for this paper, we noticed that the prevalence of eating disorders is blurry.

This is due to the different definitions of these disorders used by the physicians. Also, it is difficult to diagnose CKD in patients with eating disorders. The frequency and the mechanics of kidney disturbances are neither up to date, nor fully understood.

Once again, it seems that this type of patients is somewhat neglected.

Hemodialysis.com: What should clinicians and patients take away from your report? 

The new definitions of DSM IV should be used more often, by all types of physicians including the nephrologists. They allow a fast detection of the different risk gr

oups (e.g. restricting subtype versus the binge-eating/purging one). It is important to rapidly detect decreased GFR and electrolytes disturbances in AN patients. Using creatinine based equations is misleading and falsely reassuring in AN. Measured GFR with a reference method should be used more frequently.

The use of new biomarkers (like cystatin C) should probably be favored in the future. Measuring proteinuria is also problematic in these patients.  In AN patients, tubulointerstitial disease is more prevalent than glomerular disease.

Low molecular weight globulins are sensitive markers for this type of tubulointerstitial diseases but are not detected by dipstick testing. The use of the urinary spot protein to creatinine ratio is also potentially misleading. In patients with AN, urinary creatinine excretion might be very low compared with patients without AN because of abnormally low muscle mass.

Therefore, using the classical ratio can be falsely reassuring in these patients. In AN, we would recommend measuring proteinuria (and thus urinary cystatin C or β2-microglobulin) on a 24-hours urine collection.

Hemodialysis.com : What recommendations do you have for future research as a result of this study?  

It is essential to develop a clear epidemiology on eating disorders to better detect patients who will develop severe CKD.

Clearly, we also need additional studies with new GFR biomarkers and new urinary markers to better assess and detect CKD in these populations.

Reference:

Anorexia nervosa and the kidney
Schneiter S, Berwert L, Bonny O, Teta D, Burnier M, Vogt B.
Service nephrologie et Consultation d'hypertension, Département de médecine interne, CHUV, 1011 Lausanne.
Rev Med Suisse. 2009 Feb 25;5(192):440, 442-4.