Effects of Smoking on Subjective and Objective Measures of Pain Intensity, Functional Impairment, and Health-Related Quality of Life in Lumbar Degenerative Disk Disease

BACKGROUND: Numerous studies assessed the effects of smoking on lumbar degenerative disk disease (DDD); they focused on patient-reported outcome measures (PROMs) and yielded conflicting results. METHODS: In this 2-center study on consecutive patients receiving surgical treatment for lumbar DDD, subjective functional impairment (SFI) in terms of PROMs including visual analog scale back and leg pain, Roland-Morris, Oswestry Disability Index, Euro-Qol-5D, and a Short-Form 12 physical component summary was determined at baseline, 3 days, 6 weeks, 6 months, and 1 year postoperatively. Age- and sex-adjusted T-scores of objective functional impairment (OFI) were determined using the Timed Up and Go test up to 6 weeks postoperatively. The responder status was defined by the minimal clinically important difference. RESULTS: We analyzed 375 patients (n = 96 [25.6%] smokers and n = 279 [74.4%] nonsmokers). SFI on any of the PROMs before treatment was similar in smokers and nonsmokers. Smokers were more likely to have OFI in univariate logistic regression analysis (95% confidence interval 1.31-3.37, P = 0.002). In multivariate analysis, however, this relationship became insignificant (95% confidence interval 0.85-2.38, P = 0.184). The smoking status had no predictive capacity on the 6-week SFI or OFI responder status, and there were no differences in any of the PROMs until the 1-year follow-up. CONCLUSIONS: PROMs measuring SFI for pain intensity, functional impairment, and health-related quality of life were similar in smokers and nonsmokers before surgery for lumbar DDD, as well as postoperatively. The smoking status has negligible impact on the Timed Up and Go test, which appears to be a robust assessment tool for OFI.