To print: Select File and then Print from your browser's menu --------------------------------------------------------------------------------------- Title: DG DISPATCH - ASN: Body Mass Index Poor Outcome Predictor For Dialysis Patients URL: http://www.pslgroup.com/dg/1E4A12.htm Doctor's Guide October 17, 2000
By Cameron Johnston Special to DG News
TORONTO, CANADA -- October 17, 2000 -- Body mass index might not be as good a predictor of outcome from dialysis as nephrologists have previously thought, researchers report.
According to Dr. Rita Suri, the new research challenges that long-held idea that larger people with end-stage renal disease -- even those who in other situations would be considered obese -- fare better from dialysis than people who have normal Body mass index (BMI).
Dr. Suri, a fellow in nephrology at London Health Sciences Centre, in London, Canada, conducted the study while she was a resident at the University of Alberta, in Edmonton. She presented her findings at the annual meeting of the American Society of Nephrology, held in Toronto, Canada, over the weekend.
The study was done as a retrospective chart analysis, in which the records for 168 dialysis patients were charted and analyzed over a three-year period.
Subjects were divided into three groups according to body mass index: BMI= <21, BMI = 22-25, and BMI = >25, which are standard divisions used by life insurance companies.
Overall, there was a 26 percent mortality rate across the three-year analysis, but there were no differences in mortality or in the number of hospital admissions between the BMI groups. This was surprising and contradicts other studies, which found that heavier subjects respond more favorably to dialysis than thin or under-weight subjects, Dr. Suri said.
There was, however, a strong correlation between cardiovascular disease and serum albumin levels.
Existing cardiovascular disease carries with it a risk ratio of 3.2, while serum albumin of less than 30 g/L brings with a risk ratio of 5.4.
Asked to explain why these data varied from that seen in other studies, Dr. Suri said that, upon closer look, it appeared that subjects in the group with the lowest BMI also had the lowest incidence for cardiovascular disease, and this would have changed the mortality data.
"The lowest BMI group, in whom we expected to see the highest mortality, actually had the lowest incidence of cardiovascular disease," Dr. Suri said, adding that this might have protected them from having a higher mortality rate. On the other hand, 55 percent of those in the highest BMI group had established cardiovascular disease, as compared with a 35 percent cardiovascular disease rate in the lowest BMI group.
The second important factor was that the lowest BMI group had a higher Kt/V score, which is a means of measuring the adequacy of dialysis. This holds true with other trials showing that smaller people respond better to dialysis in general and that, according to their Kt/V scores, they are also healthier to begin with.
"Body mass index, while it's an important measure to follow, I don't think can be used as an absolute marker of somebody's morbidity and mortality, because it is confounded by so many variables," Dr. Suri said. "Mortality and morbidity are not related to one thing in hemodialysis patients -- they are multi-factorial."
"This is not an intervention study, so we can't say that because somebody has a high BMI, they will do better on dialysis -- or that, if we made them fatter, they would do better. This is not a cause and effect study. It is only a correlational study," she explained. "There are many other factors contributing to the BMI that are also contributing to morbidity and mortality, as opposed to one causing the other."
A more important goal, she said, might be to launch a study aimed at finding interventions to improve the overall nutritional status of all dialysis patients, and in the case of those who do have a high BMI, finding interventions to help them manage their cardiovascular disease. --------------------------------------------------------------------------------------------- Copyright © 1999 P\S\L Consulting Group Inc. All rights reserved. Republication or redistribution of P\S\L content is expressly prohibited without the prior written consent of P\S\L. P\S\L shall not be liable for any errors, omissions or delays in this content or any other content on its sites, newsletters or other publications, nor for any decisions or actions taken in reliance on such content. --------------------------------------------------------------------------------------------- This news story was printed from *Doctor's Guide to the Internet* located at http://www.docguide.com --------------------------------------------------------------------------------------- Return to News Story Page This site is maintained by webmaster@pslgroup.com Please contact us with any comments, problems or bugs. All contents Copyright (c) 1998 P\S\L Consulting Group Inc. All rights reserved.