Diabetes May Diminish QOL Improvement Following Lumbar Decompression
Senior author Thomas E. Mroz, MD and SpineUniverse Editorial Board Member Harel Deutsch, MD Comment
Diabetes was an independent predictor of diminished improvement in quality of life (QOL) after lumbar decompression surgery in a recent retrospective review published in the June issue of The Spine Journal. “Patients with diabetes improve following surgery, but improve less than patients without diabetes,” said senior author Thomas E. Mroz, MD, Director of Center for Spine Health, Director and Spine Surgery Fellowship Program at the Cleveland Clinic.
The study subjects (n=212) underwent lumbar decompression between 2008 and 2014 at a single center, and were followed for a minimum of 6 months postoperatively (mean follow-up, 9 months). Thirty of these patients had diabetes, and the remaining 182 did not.
The primary outcome measures were change from baseline on the following measures: EuroQol 5-Dimensions (EQ-5D), Pain Disability Questionnaire (PDQ), and Patient Health Questionnaire 9 (PHQ-9). A secondary outcome was postoperative change in QOL measures exceeding the minimally important differences (MCIDs).
As shown in the Table, subjects without diabetes showed significant improvements in all primary outcome measures, while participants with diabetes did not. In addition, a significantly greater proportion of patients without diabetes achieved the EQ-5D MCID compared with patients with diabetes (55% vs 23%: P<0.01).
Chronic kidney disease and diabetes were significant independent predictors of diminished improvement in EQ-5D postoperatively, according to multivariable regression analysis (β=−0.15 and –0.05, respectively; P=0.04 for both comparisons). In addition, diabetes was a significant independent predictor of failure to achieve an EQ-5D MCID (OR 0.20, P<0.01).
“For patients with diabetes, close regulation under the care of their doctor and adherence to diet and exercise regimen are key. Further, it is very important to maintain tight blood glucose control perioperatively,” Dr. Mroz said. He added that patients should be counseled preoperatively about the potential impact of diabetes on QOL outcomes following lumbar decompression surgery.
Lack of Change in EQ-5D May Reflect Underlying Diabetes
“Silverstein et al report on 212 patients and conclude that diabetic patients were more likely to have decreased improvement on EQ-5D questionnaires after spine surgery,” commented Harel Deutsch, MD, Associate Professor of Neurosurgery, Rush University Medical Center, Chicago. The paper further concludes that since diabetic patients are less likely to improve, therefore, we should be more selective in choosing diabetic patients for surgery.
“The paper doesn’t include what EQ-5D assesses,” Dr. Deutsch said. “The questionnaire has only 5 questions. One question involves mobility and assesses a person’s walking ability. The second question assesses a person’s ability to dress himself. The third question asks about doing ‘usual activities.’ The fourth question assesses pain. The final question assesses depression and anxiety.”
“Certainly, all the EQ-5D question's results are affected by diabetes and other chronic diseases,” Dr. Deutsch noted. “Therefore, the lack of improvement in EQ-5D scores in diabetic patients doesn’t necessary mean that surgical intervention is less effective in diabetic patients. More likely, the surgery cannot reverse the patient’s diabetes and decreased scores are a function of the patients’ underlying chronic disease. While some articles have suggested a higher complication rate in diabetic patients, the rates of complications are not sufficiently different to treat diabetic patients differently than other patients.”