The Impact of Data Characteristics on the Selection of Data Mining Methods for Predictive Classification

This research-in-process is exploring a contingency approach to the construction and selection of data mining models for predictive classification. This approach considers the structure of the data set and the relationships between and among the various attributes characterizing the data set, with the goal of selecting a model that provides greater insight into the data – and therefore predicts most accurately -- given a particular data structure. Preliminary results obtained from analysis of hospital patient records indicate that concentration indices, commonly used to measure firm concentration within an industry, are useful in characterizing data set structures and therefore in guiding the model selection process. The eventual goal of this research is the construction of a decision support system that can aid decision makers in the model selection task

Modeling ischemia-induced dyssynchronous myocardial contraction

Left ventricular (LV) contraction dyssynchrony is not easily quantified. We previously described a model for quantifying LV dyssynchrony that referenced regional amplitude and phase angles to global LV systole using esmolol-induced regional dyskinesis. We tested the hypothesis that our sine wave model and phase angle analysis of regional dyssynchrony in a canine model could also assess dyssynchrony of contraction during regional ischemia. Hence we compared intracoronary esmolol and matched regional ischemia in 10 anesthetized open-chest dogs. Regional and total LV volumes (conductance catheter), piezoelectric crystal shortening, and LV pressures were measured before, during, and after esmolol-induced apical dyskinesis and matched regional ischemia. We defined regional phase angle of contraction (α) as the relative distance, measured in degrees, that regional minimal volume differed from global end-systole. We also compared maximal stroke volume (SV), observed effective SV (that portion of regional SV contributing to total SV for each treatment), and calculated effective SV (total regional SV x cosine α). Dobutamine infusion increased homogeneity of regional α relative to baseline. Both esmolol and ischemia significantly delayed (P < 0.05) apical contraction as quantified by increased α (12.4° ± 28.1° to 27.4° ± 30.4° and 54.2° ± 32.6°, respectively) (mean ± sd) and decreased regional effective SV (4.7 ± 2.5 mL to 3.6 ± 2.2 mL and 4 ± 2.5 mL, respectively) relative to baseline. Our study indicates that intracoronary esmolol and ischemia induced qualitatively similar mechanical effects on myocardial function and that a sine wave model to estimate regional effective SV is a sensitive method to detect and quantify regional dyssynchrony induced by ischemia. Potentially, phase angle and regional amplitude analyses may prove to be effective measures to identify and quantify the beneficial effects of resynchronization therapies on myocardial function. © 2006 by International Anesthesia Research Society

Comparing algorithms for composite measures of intra-disease multiple medication adherence: The case of diabetes

Background Adherence to multiple medications (i.e., separate dosage forms) intended for a disease can be measured by different single estimators, termed as composite estimators of intra-disease multiple medication adherence: 80% days covered (a) by at least one medication (“at least one”); (b) by both medications (“both”); (c) by each medication measured separately (“all”); and (d) computing an average of the individual medication adherence estimates (“average”). Objectives (a) Assess different composite adherence estimators regarding their ability to predict healthcare utilization; (b) compare and contrast composite estimators. Methods Using MarketScan 2002–2003 data, 6043 nonelderly patients who filled separate prescriptions of sulfonylurea [SU] and thiazolidinedione [TZD] were identified. Adherence was measured by the proportion of days covered (PDC) over periods of 90 days, 30 days, and cumulatively over such periods. Cox proportional hazards models analyzed all-cause and diabetes-related emergency room (ER) visits as the outcome variables. Results All composite measures predicted hazards of all-cause or diabetes ER visits (P \u3c 0.001) and each measure showed statistically significant discriminatory power (concordance statistics from 0.55 to 0.58). Cox regression was performed multiple times in which composite estimators measured on a continuous scale (e.g., ‘average’) were dichotomized using several cut-points. In the majority of cases (≤3 out of 8 times in analyses of ER outcomes), optimal results did not occur when the dichotomization cut-point was set at 80%. Conclusions Each composite estimator showed the fundamental quality of a good measure. Although ‘average’ and ‘all’ approaches offer ease of measurement, there was no clear trend in superiority of one measure over the others. Clinical and practical considerations should dictate the choice of measure

Cost-analysis of in-office versus operating room sialendoscopy: Comparison of cost burden and outcomes

PURPOSE: Office-based procedures in otolaryngology are increasingly utilized to increase efficiency, reduce cost, and eliminate risks associated with surgery. Gland-preserving surgical management of sialadenitis and sialolithiasis are often performed in the operating room, although many surgeons are moving this practice to clinic. We aim to determine the difference in patient charges and perioperative outcomes for salivary gland procedures performed in the clinic versus the OR. METHODS: Retrospective series of patients presenting with sialolithiasis, acute or chronic sialadenitis, and stricture between 2010 and 2019. Demographics, perioperative variables, setting, and charge data were collected. RESULTS: 528 patients underwent operative intervention (n = 427 office, n = 101 OR). Cohort demographics were comparable. Sialolithiasis was the most common presenting diagnosis in both cohorts. Both cohorts had similar rates of complete (p = 0.09) and partial (p = 0.97) response to treatment. A higher percentage of patients in the OR group reported no improvement (21.4 vs 12.2%, p = 0.034). Overall complications were similar (p = 0.582). Mean charges were statistically greater in the OR ($5560.35 OR vs$1298.33 office, p \u3c 0.001). Operative time was significantly reduced in the office group (21.8 min vs 60.85 min, p \u3c 0.001). CONCLUSIONS: Appropriately selected patients can be successfully treated in outpatient clinic without compromising patient safety or quality while significantly reducing the financial burden to patients and the healthcare system

The Science of Safety Curriculum in US Colleges and Schools of Pharmacy

Objective. To describe the integration of science of safety (SoS) topics in doctor of pharmacy (PharmD) curricula of US colleges and schools of pharmacy