OBJECTIVE: Children evaluated in the emergency department for possible appendicitis are often admitted for observation, despite the widespread availability of accurate diagnostic studies, particularly computed tomography (CT). We sought to establish effective and efficient strategies for using CT to diagnose and manage children with possible appendicitis. DESIGN: Retrospective chart review and decision analysis. Setting. Emergency department of a large, urban tertiary care pediatric teaching hospital. PATIENTS: All patients admitted from January 1996 to August 1997 for suspected appendicitis. METHOD OF ANALYSIS: Three modeled strategies were empirically applied to the retrospective cohort of patients admitted for observation. Outcomes and costs under the modeled strategies were compared with those under current practice. The three strategies were: 1) to obtain CT scans on all patients and discharge those with normal findings; 2) to obtain CT scans and admit all patients; 3) to selectively obtain CT scans on those patients with a peripheral white blood cell count >10 000/mm(3) (10 x 10(9)/L) and admit all. The sensitivity and specificity of CT for diagnosing appendicitis were determined empirically from the data. A sensitivity analysis was performed. MAIN OUTCOME MEASURES: The number of preoperative inpatient observation days, total hospital costs, and the rates of both missed appendicitis and negative laparotomies. RESULTS: Of 609 patients hospitalized for possible appendicitis, 287 went directly to the operating room and 14 patients had known perforation and abscess. Three hundred eight children were observed and comprised the study cohort. Of the cohort, 112 (36.4%) underwent appendectomy and 26 (23.2%) of these had a normal appendix at pathology. Three patients were discharged from the hospital after observation and were subsequently readmitted with appendicitis (missed appendicitis). Among the 75 patients who had CT performed, the sensitivity and specificity of CT were both 97%. Under the current practice strategy, the cohort collectively accumulated 487 inpatient observation days and incurred a per patient cost of $5831. All three CT strategies would have reduced the total number of inpatient observation days, operations, negative laparotomies, as well as the per patient cost. The strategy of obtaining CT scans on all patients and then admitting them had the lowest rate of missed appendicitis. The additional cost of preventing each case of missed appendicitis under this strategy compared with the strategy of obtaining CT scans and sending home those with negative findings was $150,304. Even at the lowest reported sensitivity and specificity of CT in the literature, the ordering of the three strategies remained constant and continued to reduce total cost per patient. CONCLUSION: Compared with current practice, diagnostic strategies using CT could reduce costs and improve diagnosis, management, and outcomes for children with appendicitis.

BACKGROUND: Medication nonadherence costs $300 billion annually in the US. Medicare Advantage plans have a financial incentive to increase medication adherence among members because the Centers for Medicare and Medicaid Services (CMS) now awards substantive bonus payments to such plans, based in part on population adherence to chronic medications. We sought to build an individualized surveillance model that detects early which beneficiaries will fall below the CMS adherence threshold. METHODS: This was a retrospective study of over 210,000 beneficiaries initiating statins, in a database of private insurance claims, from 2008-2011. A logistic regression model was constructed to use statin adherence from initiation to day 90 to predict beneficiaries who would not meet the CMS measure of proportion of days covered 0.8 or above, from day 91 to 365. The model controlled for 15 additional characteristics. In a sensitivity analysis, we varied the number of days of adherence data used for prediction. RESULTS: Lower adherence in the first 90 days was the strongest predictor of one-year nonadherence, with an odds ratio of 25.0 (95% confidence interval 23.7-26.5) for poor adherence at one year. The model had an area under the receiver operating characteristic curve of 0.80. Sensitivity analysis revealed that predictions of comparable accuracy could be made only 40 days after statin initiation. When members with 30-day supplies for their first statin fill had predictions made at 40 days, and members with 90-day supplies for their first fill had predictions made at 100 days, poor adherence could be predicted with 86% positive predictive value. CONCLUSIONS: To preserve their Medicare Star ratings, plan managers should identify or develop effective programs to improve adherence. An individualized surveillance approach can be used to target members who would most benefit, recognizing the tradeoff between improved model performance over time and the advantage of earlier detection.