Prediction of quality of life improvements in patients with lumbar stenosis following use of membrane stabilizing agents.

OBJECTIVE: Membrane stabilizing agents (MSAs) improves function and reduces neuropathic pain in a subset of patients with LSS. No study has investigated the pre-treatment demographic and psychosocial factors associated with quality of life (QOL) outcomes following the use of MSAs. In this study we sought to create prediction models for post-treatment outcome.

METHODS: All patients who were diagnosed with LSS and treated with MSAs at a single institution between September 2010 and March 2013 were retrospectively reviewed. QOL outcomes were collected prospectively. Prediction tools were created using multivariable logistic regression and Cox proportional hazard models. Outcome measures were: 1 - need for surgery within 1 year after initiating MSA treatment, 2 - time until surgery after initiating MSA treatment, 3 - any improvement in EuroQol (EQ)-5D QOL index, 4 - improvement in EQ-5D index exceeding the minimum clinically important difference (MCID).

RESULTS: 1346 patients were included. For goal 1 (need for surgery), the prediction model was less robust. For goal 2 (time to surgery), only age was a significant predictor, with each 10-year increase in age causing the hazard of eventually having surgery to increase by 20%. 382 patients were available for analysis for goals 3 and 4 (predicting improvement in EQ-5D). Prediction models for these goals were good with C-statistics 0.73 and 0.85, respectively. Predictive factors for superior outcomes included lower baseline EQ-5D index (worse QOL), less baseline depression, greater median income, and being married.

CONCLUSION: MSA treatment provides improvements in quality of life for those individuals with LSS. Treatment effects of MSAs will be greatest in those with worse quality of life, less depression, married patients, and those of higher socio-economic status.