The impact of diabetes upon quality of life outcomes after lumbar decompression.

BACKGROUND CONTEXT

Patients with comorbid disease may experience suboptimal quality of life (QOL) improvement following decompression spinal surgery. Prior studies have suggested the deleterious effect of diabetes upon postoperative QOL; however, these studies have not used minimal clinically important differences (MCIDs) or multivariable statistical techniques.

PURPOSE

The purpose of this study was to assess the effect of preoperative diabetes upon postoperative change in QOL.

STUDY DESIGN/SETTING: A retrospective cohort study at a single tertiary-care center was carried out.

PATIENT SAMPLE

Patients who underwent lumbar decompression between 2008 and 2014 were included in the study. Inclusion necessitated a minimum follow-up of 6 months.

OUTCOMES MEASURES

Postoperative changes in the EuroQol 5-Dimensions (EQ-5D), Pain Disability Questionnaire (PDQ), and Patient Health Questionnaire 9 (PHQ-9) at last follow-up were the primary outcome measures. The secondary outcome variable was postoperative change in QOL measures exceeding the MCID.

METHODS

Quality of life data were collected using the institutional prospectively collected database of patient-reported health status measures. Simple and multivariable logistic regressions were used to assess the impact of diabetes upon normalized change in QOL and improvement exceeding the MCID.

RESULTS

There were 212 patients who met inclusion criteria. Whereas non-diabetics experienced significant improvements in EQ-5D, PDQ, and PHQ-9 (p<.01), diabetics experienced no significant changes in any measures. More non-diabetics achieved the EQ-5D MCID compared with diabetics (55% vs. 23%, p<.01). Following multivariable regression, chronic kidney disease (CKD, β=-0.15, p=.04) and diabetes (β=-0.05, p=.04) were identified as significant independent predictors of diminished improvement in EQ-5D postoperatively. Furthermore, diabetes was also identified as a significant independent predictor of failure to achieve an EQ-5D MCID (OR 0.20, p<.01), whereas CKD trended toward predicting diminished improvement (OR<0.01, p=.09).

CONCLUSION

The burden of comorbidities may impact the QOL benefit of decompression spine surgery. In the present study, diabetes was found to independently predict diminished improvement in QOL after lumbar decompression.