ABSTRACT
Background: Model for end-stage liver disease (MELD) is currently used for liver transplantation (LT) allocation, however, it is not a sufficient criterion. Objective: This current study aims to perform a hybrid neural network analysis of different data, make a decision tree and finally design a decision support system for improving LT prioritization. Material and Methods: In this cohort follow-up-based study, baseline characteristics of 1947 adult patients, who were candidates for LT in Shiraz Organ Transplant Center, Iran, were assessed and followed for two years and those who died before LT due to the end-stage liver disease were considered as dead cases, while others considered as alive cases. A well-organized checklist was filled for each patient. Analysis of the data was performed using artificial neural networks (ANN) and support vector machines (SVM). Finally, a decision tree was illustrated and a user friendly decision support system was designed to assist physicians in LT prioritization. Results: Between all MELD types, MELD-Na was a stronger determinant of LT candidates' survival. Both ANN and SVM showed that besides MELD-Na, age and ALP (alkaline phosphatase) are the most important factors, resulting in death in LT candidates. It was cleared that MELD-Na <23, age <53 and ALP <257 IU/L were the best predictors of survival in LT candidates. An applicable decision support system was designed in this study using the above three factors. Conclusion: Therefore, Meld-Na, age and ALP should be used for LT allocation. The presented decision support system in this study will be helpful in LT prioritization by LT allocators.
ABSTRACT
Introduction: The statistical quality of many trial-based economic evaluations is poor. When conducting trial-based economic evaluations, researchers often turn to national pharmacoeconomic guidelines for guidance. Therefore, this study reviewed which recommendations are currently given by national pharmacoeconomic guidelines on the statistical analysis of trial-based economic evaluations.Areas covered: 40 national pharmacoeconomic guidelines were identified. Data were extracted on the guidelines' recommendations on how to deal with baseline imbalances, skewed costs, correlated costs and effects, clustering of data, longitudinal data, and missing data in trial-based economic evaluations. Four guidelines (10%) were found to include recommendations on how to deal with baseline imbalances, five (13%) on how to deal with skewed costs, and seven (18%) on how to deal with missing data. Recommendations were very general in nature and recommendations on dealing with correlated costs and effects, clustering of data, and longitudinal data were lacking.Expert opinion: Current national pharmacoeconomic guidelines provide little to no guidance on how to deal with the statistical challenges to trial-based economic evaluations. Since the use of suboptimal statistical methods may lead to biased results, and, therefore, possibly to a waste of scarce resources, national agencies are advised to include more statistical guidance in their pharmacoeconomic guidelines.
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Clinical Trials as Topic/methods , Economics, Pharmaceutical , Guidelines as Topic , Data Interpretation, Statistical , Humans , Research DesignABSTRACT
PURPOSE: To evaluate the test-retest reliability and compare the static and dynamic postural control values in competitive athletes following anterior cruciate ligament (ACL) reconstruction and controls. METHODS: Thirty athletes, 8.4 ± 1.8 months after ACL reconstruction, and thirty healthy matched controls were asked to execute single-leg stance and single-legged drop jump tests onto a force plate. Amplitude and velocity in anteroposterior and mediolateral directions, and mean total velocity were measured for static evaluation. Peak vertical ground reaction force (PVGRF) during landing and takeoff and loading rate were measured for dynamic evaluation. To evaluate test-retest reliability, 15 participants of each group repeated the tests 6-8 days after the first session. Mixed model of analysis of variance was used to determine differences between the involved, uninvolved, and control limbs. The test-retest reliability was measured using intraclass correlation coefficient and standard error of measurement. RESULTS: Greater postural sway has been observed in the operated leg of ACL-reconstructed athletes compared with the non-operated side (P < 0.01) and the matched limb of the control group (P < 0.01). During landing, PVGRF and loading rate on the uninvolved limb of the athletes who had undergone ACL reconstruction were greater in comparison with those of the control group (P < 0.001). Both static and dynamic postural measures have high test-retest reliability, ranging from 0.73 to 0.88. CONCLUSIONS: Static and dynamic postural measures are reliable tests to evaluate functional performance of athletes following ACL reconstruction. Eight months postsurgery, competitive athletes still demonstrated postural asymmetries, compared to matched controls, which might result in their susceptibility to future ACL injury. LEVEL OF EVIDENCE: Prognostic study, case-control, Level III.
