Diabetes and Chronic Kidney Disease Linked to Suboptimal Quality of Life Benefit After Lumbar Decompression
Commentary by Peter G. Whang, MD, FACS
Patients with diabetes and chronic kidney disease do not experience expected improvements in quality of life following lumbar decompression in the treatment of lumbar degenerative disease, according to a retrospective cohort study by Silverstein et al published online ahead of print in The Spine Journal.
“In this study, patients with diabetes mellitus or chronic kidney disease exhibited significantly less improvement in quality of life measures following lumbar decompression procedures compared to those without these comorbidities,” commented Peter G. Whang, MD, FACS, Associate Professor of Orthopaedics and Rehabilitation at the Yale University School of Medicine in New Haven, CT. “Thus, as with other conditions such as smoking and depression, which have previously been shown to be associated with poorer postoperative outcomes, it appears as if individuals with diabetes may also be expected to experience less benefit from these types of surgeries.”
The researchers examined postoperative change in quality of life measures among 212 patients (age ≥18 years) who underwent elective lumbar decompression without fusion for degenerative indications between 2008 and 2014. The patients were followed for a minimum of 6 months after surgery. While not all the patients were routinely screened for diabetes, 30 patients had a fasting glucose screen >126 mg/dL or hemoglobin A1C >6.5% and were considered to have diabetes.
While previous studies have demonstrated that medical comorbidities, such as diabetes, are associated with suboptimal clinical outcomes after lumbar spine surgery, conflicting results have been reported regarding the effects of diabetes on patient satisfaction following surgery. In addition, previous studies often did not incorporate minimal clinically important differences (MCID) or multivariable techniques in the analysis.
No Improvement in QOL Found Among Patients With Diabetes
The patients without diabetes—but not patients with diabetes—showed significant improvements in the following quality of life (QOL) measures: EuroQol 5-Dimensions (EQ-5D), Pain Disability 7 Questionnaire (PDQ), and Patient Health Questionnaire-9 (PHQ-9). Among patients with diabetes, A1C level was not significantly associated with outcomes on any of these measures.
More patients without diabetes achieved EQ-5D MCID (0.1) following surgery compared with the diabetes group (55% vs 23%; P<0.01). Following multivariable regression, chronic kidney disease (β=-0.15, P=0.04) and diabetes (β=-0.05, P=0.04) were significant independent predictors of diminished improvement in EQ-5D. Furthermore, diabetes was also identified as a significant independent predictor of failure to achieve an EQ-5D MCID (odds ratio, 0.20, P<0.01), while a trend toward diminished improvement was found among patients with chronic kidney disease (odds ratio, <0.01, P=0.09). Notably, only 3 patients (1%) in the overall cohort had chronic kidney disease.
Implications for Patient Selection and Informed Consent
“While we as surgeons like to think that we can help everyone equally with the interventions that we perform, there is an increasing amount of evidence suggesting that there are a number of patient characteristics and medical comorbidities that will likely compromise the results of lumbar decompression,” commented Dr. Whang. “The findings of this investigation suggest that it may be important for us to be more judicious about recommending operative treatment for patients with diabetes who are not only at greater risk for complications, but also are less likely to achieve meaningful improvements in quality of life and other clinically relevant metrics.”
“In addition, it is also critical that this information also be shared with any patients with these conditions who do elect to proceed with surgery as part of the informed consent process in order to ensure that they have reasonable expectations regarding their treatment,” Dr. Whang said.
“It is important to point out that there are some methodological limitations to this analysis, and it does not elucidate the mechanisms by which this disease reduces the improvements in quality of life observed after lumbar decompression,” Dr. Whang added. “Thus, prospective studies are certainly warranted and will hopefully further characterize the deleterious effects that diabetes and other medical comorbidities may have upon the surgical outcomes of our patients.”