Estimation, power and sample size calculations for stochastic cost and effectiveness analysis

Various methods have been proposed to address uncertainty in economic evaluations of healthcare programmes. One approach suggested in the literature is to estimate separate confidence intervals for the incremental costs and effects of a new health programme in comparison with an existing programme. These intervals are then combined to generate a rectangular confidence region in the cost-effectiveness plane that implicitly defines a corresponding confidence interval for the incremental cost-effectiveness ratio (ICER). The same approach has been used to calculate sample sizes and study power. This application of the rectangle method is consistent with the adoption of ICERs and a threshold as a decision rule, this being the most commonly used approach in empirical applications of cost-effectiveness analysis, as well as the one recommended by agencies that assess medical technology around the world. In this paper, we first outline the rectangle method, and then propose a modification that recognises that separate inferences are being drawn on the cost and effectiveness domains, and that corrects for multiple statistical comparisons. The confidence rectangle is otherwise too small, the corresponding confidence interval for the ICER is too narrow and sample sizes are under-estimated. Our modification corrects these problems. A further difficulty is that the placement of the confidence rectangle around the null value is somewhat arbitrary, and does not correspond to a unique value of ICERs. As a result, different values of sample size and power for the estimation of ICERs can be obtained, depending on the null values of the cost and effectiveness. We conclude that it is important to clearly identify the analytic goal in terms of estimating differential costs, differential effects or a combination of the two using the ICER index. These ideas are illustrated using numerical examples.     

Portfolio theory and the alternative decision rule of cost-effectiveness analysis: theoretical and practical considerations

Bridges and Terris (Soc. Sci. Med. (2004)) critique our paper on the alternative decision rule of economic evaluation in the presence of uncertainty and constrained resources within the context of a portfolio of health care programs (Sendi et al. Soc. Sci. Med. 57 (2003) 2207). They argue that by not adopting a formal portfolio theory approach we overlook the optimal solution. We show that these arguments stem from a fundamental misunderstanding of the alternative decision rule of economic evaluation. In particular, the portfolio theory approach advocated by Bridges and Terris is based on the same theoretical assumptions that the alternative decision rule set out to relax. Moreover, Bridges and Terris acknowledge that the proposed portfolio theory approach may not identify the optimal solution to resource allocation problems. Hence, it provides neither theoretical nor practical improvements to the proposed alternative decision rule.     

High-resolution functional optical imaging: from the neocortex to the eye

Much work remains to be done to establish the clinical usefulness of the RFI for early diagnosis and treatment guidance. The discoveries obtained by functional optical imaging of the neocortex in the last 15 years and the recent RFI studies of the eyes of normal subjects and patients with diabetic retinopathy, glaucoma, and age-related macular degeneration suggest that functional optical imaging of the retina is likely to become a multi-modality powerful clinical tool.     

Enoxaparin can be used safely in patients with severe thrombocytopenia due to intensive chemotherapy regimens

Treatment with intensive chemotherapy regimens is frequently complicated by severe thrombocytopenia. During the period of severe thrombocytopenia, anticoagulant treatment is not uncommonly indicated for thromboembolic events or thromboprophylaxis in these patients. We report 10 hematological patients treated with intensive chemotherapy protocols that were anticoagulated with enoxaparin for catheter related central venous thrombosis and thromboprophylaxis. During the period of severe thrombocytopenia the dosages of enoxaparin were reduced and no major bleeding occurred. Based on our experience we suggest that reduced dosages of low molecular weight heparins may be used relatively safely during transient severe thrombocytopenia.     

Intraperitoneal levonorgestrel-releasing intrauterine device following uterine perforation: the role of progestins in adhesion formation

BACKGROUND: Intrauterine contraception is a widely used, highly effective means of birth control. Uterine perforation is a serious, albeit rare, complication of intrauterine device (IUD) use. Although uterine perforation by levonorgestrel-releasing (20 micro g/day) intrauterine system (LNG-IUS) has already been reported, the peritoneal adhesion potential of this IUD is unknown. METHODS: The medical files of all patients diagnosed with an intra-peritoneal IUD between the years 1990-2002 at Hadassah Medical Center were reviewed. Histopathological study of peritoneal adhesion tissue adjacent to levonorgestrel medicated IUD was conducted in one case. RESULTS: Eight cases of dislocated IUDs were found. Four cases used LNG-IUS and four other cases used copper-IUD. Laparoscopy for IUD removal disclosed mild local peritoneal adhesions between omentum and pelvic organs in all cases. No difference was noted in the appearance of the peritoneum in the presence of either a copper-IUD or LNG-IUS. Histological examination of peritoneal tissue encasing the levonorgestrel-intrauterine system revealed loose connective tissue with aggregates of submesothelial cells with a pseudo-decidual change. Immunohistochemical staining for progesterone receptor was negative. CONCLUSIONS: The peritoneal adhesions potential of LNG-IUS is low, similar to that of the copper-bearing IUD.     

The web of coping resources and pathways to reemployment following a job loss

Structural equation modeling analyses of data from 2 longitudinal community studies of recently laid-off workers examined the interrelationships and pathways from personal coping resources to job-search intensity and the extent and quality of reemployment at 2 follow-ups (at 6 months and at 12 or 24 months). In both studies, the proposed models for predicting reemployment and reemployment quality provided a good fit to the data with the same pattern of results, which demonstrated that job-search motivation increased reemployment at all follow-ups but did not affect reemployment quality. At both the 6- and 12-month follow-ups, level of depressive symptoms decreased the extent and quality of reemployment. The results also highlighted the dual role of financial strain, which on the one hand facilitates reemployment by increasing job-search motivation and job-search intensity and on the other hand inhibits it by increasing depressive symptoms.     

Quality of life of individuals with heart failure: a randomized trial of the effectiveness of two models of hospital-to-home transition

BACKGROUND: The growing number of patients with congestive heart failure has increased both the pressure on hospital resources and the need for community management of the condition. Improving hospital-to-home transition for this population is a logical step in responding to current practice guidelines' recommendations for coordination and education. Positive outcomes have been reported from trials evaluating multiple interventions, enhanced hospital discharge, and follow-up through the addition of a case management role. The question remains if similar gains could be achieved working with usual hospital and community nurses. METHODS: A 12-week, prospective, randomized controlled trial was conducted of the effect of transitional care on health-related quality of life (disease-specific and generic measures), rates of readmission, and emergency room use. The nurse-led intervention focused on the transition from hospital-to-home and supportive care for self-management 2 weeks after hospital discharge. RESULTS: At 6 weeks after hospital discharge, the overall Minnesota Living with Heart Failure Questionnaire (MLHFQ) score was better among the Transitional Care patients (27.2 +/- 19.1 SD) than among the Usual Care patients (37.5 +/- 20.3 SD; P = 0.002). Similar results were found at 12 weeks postdischarge for the overall MLHFQ and at 6- and 12-weeks postdischarge for the MLHFQ's Physical Dimension and Emotional Dimension subscales. Differences in generic quality life, as assessed by the SF-36 Physical component, Mental Component, and General Health subscales, were not significantly different between the Transition and Usual Care groups. At 12 weeks postdischarge, 31% of the Usual Care patients had been readmitted compared with 23% of the Transitional Care patients (P = 0.26), and 46% of the Usual Care group visited the emergency department compared with 29% in the Transitional Care group (chi2 = 4.86, df 1, P = 0.03). CONCLUSIONS: There were significant improvements in health-related quality of life (HRQL) associated with Transitional Care and less use of emergency rooms.