Diabetes, hypertension and obesity negatively effect joint replacement outcomes

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Diabetes, hypertension and obesity negatively effect joint replacement

outcomes

01 Jun 2005

Using a database of nearly 1 million Americans who underwent major

joint replacement surgery, a team led by researchers at Duke University

Medical Center have determined those surgical patients with diabetes,

hypertension or obesity were significantly more likely to suffer

post-operative complications.

The team recommended that physicians and researchers evaluate treating

such at-risk patients before surgery to control blood sugar, reduce

blood pressure and prevent dangerous clot formation, to reduce the

likelihood of complications.

These findings have broad implications for the health care delivery

system, the researchers said, since more than 700,000 major joint

replacement surgeries are performed annually in the U.S. at a cost

exceeding $10 billion. Furthermore, as the incidence of diabetes,

hypertension and obesity increases and the population ages, orthopedic

surgeons must expect to see not only more, but sicker, patients and

they will need to know how to effectively treat them, said the

researchers.

Of three conditions that the researchers studied, obesity conferred the

highest risk of post-operative complications and the need for

additional post-discharge care.

The findings of the Duke analysis were published June 1, 2005, in the

journal Clinical Orthopaedics and Related Research.

" Hypertension, diabetes and obesity are important independent

predictors of increased complications for patients undergoing major

joint replacement surgery, " said the study's first author Nitin Jain,

M.D., currently a post-doctoral fellow at Brigham & Women's Hospital,

Harvard Medical School. He conducted the study as a research associate

in the laboratory of Duke orthopedic surgeon ce Higgins, M.D.,

senior member of the research team.

" The results of our study should may surgeons to more accurately

predict which of their patients are most likely to have adverse

outcomes after their surgery, " Jain continued. " With this knowledge,

surgeons should not only be able to better counsel their patients

before surgery, but also consider strategies during and after surgery

to ensure better outcomes. However, the risks and benefits of a joint

replacement procedure should be weighed by surgeons on an individual

patient basis. "

Specifically, in their analysis of patients undergoing hip, knee or

shoulder replacement surgery, the researchers found that 3.7 percent of

obese patients experienced in-hospital complications, compared to 2.6

percent for non-obese patients. For patients with hypertension, the

rates were 2.8 percent versus 2.6 percent, and for patients with

diabetes, the ranges were 2.9 percent versus 2.6 percent.

Furthermore, the likelihood of a " non-routine " discharge from the

hospital was 30 percent higher for diabetics and 45 percent higher in

obese patients -- for patients with diabetes who were also obese, the

likelihood rose to 75 percent. Non-routine discharges are those to

another facility where further care is necessary, such as short-term

hospitals, intermediate care facilities or home health care.

For their analysis, the team consulted the Nationwide Inpatient Samples

(NIS) database. The NIS, sponsored by the U.S. Agency for Healthcare

Research and Quality, is a publicly available database of more than 8

million patients from more than 1,000 U.S. hospitals. The hospitals

vary by region, size, location, teaching status and ownership.

The Duke team's analysis identified 959,839 patients who received knee,

hip or shoulder replacements between 1988 and 2000. Overall, the

patients tended to be white (64.2 percent) and female (64.6 percent)

with an average age of 70.8 years.

" This database is a very powerful tool that can give us real-life

answers for patients and physicians facing major joint replacement

surgery, " Higgins said. " Past studies have included much smaller

numbers of patients or were conducted at a single center. The NIS is a

true reflection of what is happening across the country.

" In this case, the analysis identified a subset of patients who are at

increased risk for worse outcomes, " Higgins continued. " Our study

demonstrates the need for clinical protocols and guidelines

specifically aimed at patients with these comorbidities, as well as the

need for adequate assessment of the risks and benefits of joint

replacement procedures in these patients. "

While further studies are needed to find strategies to reduce

complication rates, the researchers said that strategies such as better

control of blood glucose levels and blood pressure during surgery need

to be evaluated as possible ways to improve the outcomes for patients

with diabetes and high blood pressure. They also recommend that the use

of blood-thinning drugs post-operatively to prevent the formation of

deep vein thrombosis (DVT), in which clots that can form deep in

muscles during extended periods of inactivity can break loose to cause

heart attacks or stroke, be evaluated.

The researchers plan to refine their analysis to include other

complicating factors as well as additional complications. They also

will investigate whether outcomes are influenced by health care

delivery factors, such as the volume of cases performed by individual

surgeons and hospitals, or patient characteristics such as age, gender

and race.

The analysis was supported by Duke's Center for Excellence in Surgical

Outcomes (CESO).