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February 20, 2003


Severe sepsis on the rise

Severe sepsis, the leading cause of death in America’s non-coronary intensive care units, is a rapidly growing problem in the United States in terms of the number of patients afflicted by the condition and the complexity of their cases, Pitt researchers reported at the 32nd Critical Care Congress in San Antonio.

Investigating trends in severe sepsis over a seven-year period, this study is the first to identify the changing epidemiology of the life-threatening disorder and its potential financial impact on intensive care units (ICUs).

Using hospital discharge data from five states over a seven-year period (1992, 1995 and 1999) and federal population and health care data, researchers determined that the annual rate of severe sepsis cases increased by 6.2 percent from 635,000 cases in 1992 to 965,000 cases in 1999.

In addition, the study team observed a 6.9 percent annual increase in the number of complex severe sepsis cases, defined by more than one organ failure, treated in the ICU. They also noted a slight increase of 2.9 percent in the proportion of severe sepsis patients admitted to ICUs each year, although the overall proportion of ICU severe sepsis cases remained consistent for all years studied, at approximately 50 percent.

Changes in the site of infection in sepsis cases in the study were relatively minor, the most notable being 4.4 percent increase in respiratory infections and a 2.5 percent decrease in urosepsis.

“The incessant growth of the severe sepsis epidemic in this country ought to be cause for grave alarm,” said investigator Derek C. Angus, associate professor of critical care medicine at Pitt’s School of Medicine. “This condition has long been one of medicine’s greatest foes, taking more lives each year than breast, colorectal, pancreatic and prostate cancer combined. Mounting numbers and more complex cases will only make severe sepsis a more formidable adversary.”

Although the annual incidence of severe sepsis cases increased overall by 6.2 percent, researchers noted a dramatic 40 percent increase in the number of elderly patients over 85 years of age with the condition. This shift resulted in a one-year increase in the average age of the American severe sepsis patient, from 63 to 64 years of age. However, despite the increases in patient age and case complexity, the study team found that, overall, sepsis-related mortality decreased slightly by approximately 4 percent over the seven-year period.

“This is the first time we’ve looked really closely at the changes in the actual patients who make up the towering mountain of severe sepsis statistics in this country,” said Angus. “What we found is that the face of severe sepsis is, on the whole, getting older than it used to be. And yet recent improvements in critical care technology have meant some patients appear to have a better chance of evading this too-often-deadly stalker.”

Although the decline in mortality associated with severe sepsis is welcome news, researchers conclude that the increasing complexity of patients’ cases, coupled with the advancing age of the typical severe sepsis patient, may necessitate increased use of costly medical procedures to optimize patient survival — a cause for concern in today’s health care cost-containment environment.

A recent survey by the Society of Critical Care Medicine revealed that attempting to control medical costs through so-called “bedside rationing” of services and medications is practiced by nearly two-thirds of critical care providers, and that 43 percent said they would ration the only FDA-approved drug for severe sepsis, drotrecogin alfa (activated), in order to control medical costs.


Normal weight elderly may still be at risk for diabetes

Elderly men and women with normal body weight still may be at risk for developing type 2 diabetes if they have large amounts of muscle fat or visceral abdominal fat, according to a Pitt study published in the February issue of the journal Diabetes Care.

“Our study found that, even though an elderly person may not be overweight, he or she might still be at risk for developing diabetes,” said Bret H. Goodpaster of the University’s Division of Endocrinology and Metabolism and principal investigator of the study. “An important factor is where in the body their excess fat is stored.”

Although the prevalence of type 2 diabetes is highest among men and women over the age of 65, the prevalence of obesity in this group is only 14 percent compared with 24 percent for people in their 50s, according to Goodpaster.

“It appears that in elderly individuals, there might be some disassociation between obesity and the risk for insulin resistance and type 2 diabetes,” he said.

The study enrolled 2,964 men and women with a mean age of 73.6 years. The group was 48.5 percent male and 58.3 percent white. Of the participants, 51 percent were classified as having normal glucose tolerance, 21 percent were classified as having impaired glucose tolerance and 24 percent as having type 2 diabetes. Muscle and fat in the thigh and abdomen were determined using CT scans. The prevalence of diabetes was higher among obese subjects than among overweight or normal weight subjects, with 30 percent of obese men and 34 percent of obese women having type 2 diabetes.

Despite similar amounts of thigh fat, the proportion of intermuscular fat was higher in subjects with type 2 diabetes and impaired glucose tolerance than in subjects with normal glucose tolerance. Also, the proportion of visceral abdominal fat was higher in men and women with type 2 diabetes and impaired glucose tolerance than in those with normal glucose tolerance.

The study found that among those with type 2 diabetes, 22 percent were normal-weight men and 12 percent were normal-weight women. Another 14 percent of men and 22 percent of women had impaired glucose tolerance. Taken from another perspective, this means that two thirds of men with type 2 diabetes were not obese. A similar pattern emerged for women. “This suggests that obesity, per se, is not required for diabetes or glucose intolerance in elderly men and women,” Goodpaster said. “Fat distribution is a key determination of insulin resistance and altered glucose homeostasis.

“The concept of the metabolically obese normal-weight individual is likely to be of great importance in understanding risk factors that drive the heightened risk of type 2 diabetes in relation to aging,” he said.

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