RESUMEN
Parkinson's disease (PD) results in progressively worsening gait and balance dysfunction that can be measured using computerized devices. We utilized the longitudinal database of the Parkinson's Disease Biomarker Program to determine if baseline gait and balance measures predict future rates of symptom progression. We included 230, 222, 164, and 177 PD subjects with 6, 12, 18, and 24 months of follow-up, respectively, and we defined progression as worsening of the following clinical parameters: MDS-UPDRS total score, Montreal Cognitive Assessment, PDQ-39 mobility subscale, levodopa equivalent daily dose, Schwab and England score, and global composite outcome. We developed ridge regression models to independently estimate how each gait or balance measure, or combination of measures, predicted progression. The accuracy of each ridge regression model was calculated by cross-validation in which 90% of the data were used to estimate the ridge regression model which was then tested on the 10% of data left out. While the models modestly predicted change in outcomes at the 6-month follow-up visit (accuracy in the range of 66-71%) there was no change in the outcome variables during this short follow-up (median change in MDS-UPDRS total score = 0 and change in LEDD = 0). At follow-up periods of 12, 18, and 24 months, the models failed to predict change (accuracy in the held-out sets ranged from 42 to 60%). We conclude that this set of computerized gait and balance measures performed at baseline is unlikely to help predict future disease progression in PD. Research scientists must continue to search for progression predictors to enhance the performance of disease modifying clinical trials.
RESUMEN
Parkinson's disease (PD) is a common neurological disorder characterized by gait impairment. PD has no cure, and an impediment to developing a treatment is the lack of any accepted method to predict disease progression rate. The primary aim of this study was to develop a model using clinical measures and biomechanical measures of gait and postural stability to predict an individual's PD progression over two years. Data from 160 PD subjects were utilized. Machine learning models, including XGBoost and Feed Forward Neural Networks, were developed using extensive model optimization and cross-validation. The highest performing model was a neural network that used a group of clinical measures, achieved a PPV of 71% in identifying fast progressors, and explained a large portion (37%) of the variance in an individual's progression rate on held-out test data. This demonstrates the potential to predict individual PD progression rate and enrich trials by analyzing clinical and biomechanical measures with machine learning.
RESUMEN
PURPOSE: To evaluate the visual and economic benefits of same-day bilateral cataract surgery versus separate-day bilateral cataract surgery in the United States. SETTING: Private practice, Amarillo, Texas, USA. DESIGN: Prospective controlled nonrandomized clinical trial. METHODS: A cohort of patients having same-day bilateral cataract surgery was age-matched with a cohort of control patients who had standard separate-day bilateral cataract surgery. The primary outcome was a comparison of the direct cost for the patient, physician, ambulatory surgery center (ASC), and third-party payer. RESULTS: The same-day cohort (42 patients, 84 eyes) had similar baseline characteristics and postoperative outcomes as the control cohort (42 patients, 84 eyes). The same-day cohort had less total distance traveled for care (P = .0039 and P < .0001 for in-town and out-of-town residents, respectively), less total time spent traveling for care (P = .0008 and P < .0001 for in-town and out-of-town residents, respectively), less total number of visits required for care (P < .0001), and less total time for vision recovery (P < .0001) than the control cohort. The physician and ASC reimbursements were lower in the same-day cohort (P = .0028 and P = .0016, respectively), whereas the total physician time spent caring for the patient in surgery was not different between the 2 groups (P = .7310). The total ASC expenses were higher in the same-day cohort (P < .0001). The total third-party payer cost was significantly less in the same-day cohort (P < .0001). CONCLUSION: Visual and economic benefits for the patient can be achieved with same-day bilateral cataract surgery in the U.S. at the present time. FINANCIAL DISCLOSURE: No author has a financial or proprietary interest in any material or method mentioned.
