22 September 2011

(Reuters Health) – Kidney damage from diabetes has jumped 34 percent in the last two decades, according to a new study in the Journal of the American Medical Association.

That means nearly seven million Americans have diabetic kidney disease, despite increases in the use of medications to stave off the problem.

“This is clearly a disturbing and highly startling finding,” said Dr. Amy Friedman, who directs of the Transplant Program at SUNY Upstate Medical University and was not involved in this study.

Diabetes is the most common cause of kidney disease, a condition that increases the risk of heart disease and death.

The researchers, based at the University of Washington, used survey data from more than 30,000 adults collected in three intervals: 1988 to 1994, 1999 to 2004, and 2005 to 2008.

The number of people who had diabetes rose from six percent in the first survey group to almost eight percent in the next set, to more than nine percent in the most recent group.

Diabetic kidney disease increased similarly, from 2.2 percent in the late 1980s to early 1990s, to 2.8 percent in the early 2000s, to 3.3 percent most recently.

“The increase in diabetic kidney disease was in direct proportion to the prevalence of diabetes,” said Dr. Ian de Boer, the lead author of the study.

For each of the three survey groups, around 35 percent of diabetics had kidney disease.

The rise in diabetes could explain the parallel rise in kidney disease, yet the use of medications thought to protect the kidneys also increased over time.

De Boer’s group found that the number of diabetics taking glucose lowering medications went up from 56 percent to 75 percent, and the number of diabetics using blood pressure lowering drugs rose from 11 percent to 40 percent.

One possible explanation for the lack of progress in stemming the rates of kidney disease might be “sedentary lifestyles or changes in dietary habits that could be counterbalancing the beneficial effects of medications,” said de Boer.

“It’s also pretty clear that, over time, the population that’s being studied is simply becoming more obese,” said Friedman, pointing out another factor that might influence the development of kidney disease.

The earliest survey group had an average body mass index — a measurement of weight relative to height — of 30, whereas the BMI of the most recent group was 33. A BMI over 30 is considered obese.

Dr. Lynda Szczech, the president of the National Kidney Foundation, told Reuters Health that the increased rate of kidney disease might actually be a reflection of the success of diabetes therapies.

The more people use the medications, the more they are able to ward off a fatal progression of kidney or heart disease, and the more likely they are to continue to live with kidney disease.

Whatever the cause of the rise in kidney disease, the financial implications are substantial.

The authors of the study note that the annual cost to Medicare for treating a person living with diabetic kidney disease ranges from $21,000 to $24,000.

De Boer’s group did not estimate the total increased costs attributable to the rise in kidney disease.

“I can say with confidence that more diabetic kidney disease is going to place a strain on health care systems,” de Boer told Reuters Health.

Friedman said that prevention — particularly focused on obesity — will make the biggest impact on stopping the rise in diabetes and related kidney destruction.

“We must embrace a much healthier approach to life, because simply applying these medications is not preventing what we hoped we could,” Friedman told Reuters Health.

This article was published in www.reuters.com on 22 June 2011.