Losing weight before having total knee replacement surgery may help patients who are obese avoid a longer hospital stay and higher costs.
Doctors have long known that obesity is associated with longer hospital stays but it was uncertain if this was due to patients having an obesity-related condition or disease. Now, researchers report in the Journal of Bone and Joint Surgery that patients who are obese -which means they have a body mass index of 30 or more – face longer hospital stays for total knee replacement surgery whether or not they have other associated conditions.
“The higher costs associated with obesity are believed to be largely due to managing comorbid medical conditions linked to obesity, such as diabetes,” said lead study author Dr. Hilal Maradit-Kremers, an associate professor of epidemiology at Mayo Clinic in Rochester, Minn. And yet in this study, “even in the absence of comorbidities, patients with obesity had longer stays and higher hospital costs.”
Obesity can lead to other health problems such as hypertension, osteoarthritis, cardiovascular disease and certain cancers. Losing weight often reduces the risk of developing these diseases. It can also help alleviate knee pain.
For the study, researchers studied more than 8,000 patients who had total knee replacements. The median age of the study participants was 68. The mean BMI was 31.6.
Chief among the findings:
- The most common patient comorbidities were hypertension and diabetes.
- Length of stay and direct medical costs were lowest for patients with BMI values in the normal to overweight range.
- Every 5-unit increase in BMI beyond 30 kg/m² was associated with higher hospitalization costs: in 2010 U.S. dollars, approximately $250 to $300 for patients undergoing TKR and $600 to $650 for patients undergoing a revision joint replacement. These estimates persisted after adjusting for comorbidities and complications.
- Every 5-unit increase in BMI beyond 30 kg/m² was associated with a mean hospital stay that was .11 days longer for patients undergoing primary TKR and .06 days longer for patients undergoing revision TKR. The data was the same for patients with and without comorbidities.
“The bottom line is that obesity is increasingly common among patients undergoing joint replacement, which creates a myriad of technical and medical challenges, and likely contributes to the financial burden of the surgery,” said senior author David G. Lewallen, MD, an orthopaedic surgeon, also from Mayo Clinic.
Source: American Association of Orthopaedic Surgeons
+ Learn about advanced techniques used in total joint replacement at Virginia Orthopaedic & Spine Specialists, which helps patients recover faster.
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