OBJECTIVE — To systematically review the incidence of posttransplantation diabetes (PTD), risk factors for its development, prognostic implications, and optimal management. RESEARCH DESIGN AND METHODS — We searched databases (MEDLINE, EMBASE, the Cochrane Library, and others) from inception to September 2000, reviewed bibliographies in reports retrieved, contacted transplantation experts, and reviewed specialty journals. Two reviewers independently determined report inclusion (original studies, in all languages, of PTD in adults with no history of diabetes before transplantation), assessed study methods, and extracted data using a standardized form. Meta-regression was used to explain between-study differences in incidence. RESULTS — Nineteen studies with 3,611 patients were included. The 12-month cumulative incidence of PTD is lower (10% in most studies) than it was 3 decades ago. The type of immunosuppression explained 74% of the variability in incidence (P 0.0004). Risk factors were patient age, nonwhite ethnicity, glucocorticoid treatment for rejection, and immunosuppression with high-dose cyclosporine and tacrolimus. PTD was associated with decreased graft and patient survival in earlier studies; later studies showed improved outcomes. Randomized trials of treatment regimens have not been conducted. CONCLUSIONS — Physicians should consider modification of immunosuppressive regimens to decrease the risk of PTD in high-risk transplant recipients. Randomized trials are needed to evaluate the use of oral glucose-lowering agents in transplant recipients, paying particular attention to interactions with immunosuppressive drugs. Diabetes Care 25:583–592, 2002

A systematic review of the literature

In interview studies, sample size is often justified by interviewing participants until reaching 'data saturation'. However, there is no agreed method of establishing this. We propose principles for deciding saturation in theory-based interview studies (where conceptual categories are pre-established by existing theory). First, specify a minimum sample size for initial analysis (initial analysis sample). Second, specify how many more interviews will be conducted without new ideas emerging (stopping criterion). We demonstrate these principles in two studies, based on the theory of planned behaviour, designed to identify three belief categories (Behavioural, Normative and Control), using an initial analysis sample of 10 and stopping criterion of 3. Study 1 (retrospective analysis of existing data) identified 84 shared beliefs of 14 general medical practitioners about managing patients with sore throat without prescribing antibiotics. The criterion for saturation was achieved for Normative beliefs but not for other beliefs or studywise saturation. In Study 2 (prospective analysis), 17 relatives of people with Paget's disease of the bone reported 44 shared beliefs about taking genetic testing. Studywise data saturation was achieved at interview 17. We propose specification of these principles for reporting data saturation in theory-based interview studies. The principles may be adaptable for other types of studies.

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What is an adequate sample size? Operationalising data saturation for theory-based interview studies

Cost Effectiveness in Health and Medicine.

eMedicine创建于1996年，由近万名临床医师作为作者或编辑参与此临床医学知识库的建设，其中编辑均是来自美国哈佛、耶鲁、斯坦福、芝加哥、德克萨斯、加州大学等各分校医学院的教授或副教授。

eMedicine

Importance Increased use of computed tomography (CT) in pediatrics raises concerns about cancer risk from exposure to ionizing radiation. Objectives To quantify trends in the use of CT in pediatrics and the associated radiation exposure and cancer risk. Design Retrospective observational study. Setting Seven US health care systems. Participants The use of CT was evaluated for children younger than 15 years of age from 1996 to 2010, including 4 857 736 child-years of observation. Radiation doses were calculated for 744 CT scans performed between 2001 and 2011. Main Outcomes and Measures Rates of CT use, organ and effective doses, and projected lifetime attributable risks of cancer. Results The use of CT doubled for children younger than 5 years of age and tripled for children 5 to 14 years of age between 1996 and 2005, remained stable between 2006 and 2007, and then began to decline. Effective doses varied from 0.03 to 69.2 mSv per scan. An effective dose of 20 mSv or higher was delivered by 14% to 25% of abdomen/pelvis scans, 6% to 14% of spine scans, and 3% to 8% of chest scans. Projected lifetime attributable risks of solid cancer were higher for younger patients and girls than for older patients and boys, and they were also higher for patients who underwent CT scans of the abdomen/pelvis or spine than for patients who underwent other types of CT scans. For girls, a radiation-induced solid cancer is projected to result from every 300 to 390 abdomen/pelvis scans, 330 to 480 chest scans, and 270 to 800 spine scans, depending on age. The risk of leukemia was highest from head scans for children younger than 5 years of age at a rate of 1.9 cases per 10 000 CT scans. Nationally, 4 million pediatric CT scans of the head, abdomen/pelvis, chest, or spine performed each year are projected to cause 4870 future cancers. Reducing the highest 25% of doses to the median might prevent 43% of these cancers. Conclusions and Relevance The increased use of CT in pediatrics, combined with the wide variability in radiation doses, has resulted in many children receiving a high-dose examination. Dose-reduction strategies targeted to the highest quartile of doses could dramatically reduce the number of radiation-induced cancers.

https://jamanetwork.com/journals/jamapediatrics/articlepdf/1696279/poi130056.pdf

The Use of Computed Tomography in Pediatrics and the Associated Radiation Exposure and Estimated Cancer Risk

Tenofovir and entecavir are the most effective antiviral agents for chronic hepatitis B: a systematic review and Bayesian meta-analyses

Purpose: To compare the cost-effectiveness of different imaging strategies in the diagnosis of pediatric appendicitis by using a decision analytic model. Materials and Methods: Approval for this retrospective study based on literature review was not required by the institutional Research Ethics Board. A Markov decision model was constructed by using costs, utilities, and probabilities from the literature. The risk of radiation-induced cancer was modeled by using the Biological Effects of Ionizing Radiation VII report, which is based primarily on data from atomic bomb survivors. The three imaging strategies were ultrasonography (US), computed tomography (CT), and US followed by CT if the initial US study was negative. The model simulated the short-term and long-term outcomes of the patients, calculating the average quality-adjusted life span and health care costs. Results: For a single abdominal CT study in a 5-year-old child, the lifetime risk of radiation-induced cancer would be 26.1 per 100 000 in femal...

https://pubs.rsna.org/doi/pdf/10.1148/radiol.2502080100

Acute appendicitis in young children: cost-effectiveness of US versus CT in diagnosis--a Markov decision analytic model.

With the growth in the use of health economic evaluation to inform healthcare resource allocation decisions, the challenges in applying standard methods to child health have become apparent. A unique limitation is the paucity of child-specific preference-based measures. A single, valid, preference-based measure of utility that can be used in children of all ages does not exist. Thus, the ability to derive a QALY for use in cost-utility analysis (CUA) is compromised. This paper presents and discusses existing and novel options for deriving utilities for paediatric health states for use in CUAs. While a direct elicitation may be preferred, a child's ability to complete a standard gamble or time trade-off task is hampered by cognitive and age limitations. The abstract notions contained in indirect instruments such as the EQ-5D and Health Utilities Index may also pose challenges for young children. Novel approaches to overcome these challenges include the development of age-appropriate instruments such as the EQ-5D-Y, the development of new child-specific utility instruments such as the Child Health Utility-9D and the re-calibration of existing adult instruments to derive preference weights for health states from children themselves. For children aged <6 years, researchers have little choice but to use a proxy reporter such as parents. While parents may be reliable reporters for physical activity limitations and externally manifest symptoms, their ability to accurately report on subjective outcomes such as emotion is questionable. Catalogues of utility weights for a range of conditions are increasingly becoming available but retain many of the same limitations as valuing health states from children or from proxies. Given the dynamic relationship in quality of life (QOL) between family members when a child is ill, it seems appropriate to consider a 'family perspective' rather than an individual perspective in child health state valuation. In a collective approach, health state utilities derived from multiple family members may be combined mathematically. Alternatively, in a unitary approach, a single utility estimate may be determined to represent the family's perspective. This may include deriving utilities through parent-child dyad estimation or by using a household model that combines the utility weights of the patient and family members, incorporating reciprocal QOL effects. While these various approaches to child health state valuation represent novel research developments, the measurement challenges and threats to validity persist. Given the importance of non-health benefits to child health, especially in the domains of education and public policy, it may be worthwhile to consider an approach that allows incorporation of externalities to produce a cost-benefit analysis. The use of discrete-choice methods to assess willingness to pay for novel child health interventions holds promise as a means to produce meaningful economic evidence. Regardless of the approach taken, the highest degree of methodological rigour is essential. The increasing attention being paid by health economic researchers to the measurement challenges of paediatric health state valuation can only increase the value of child health economic evidence for decision making.

Challenges in health state valuation in paediatric economic evaluation: are QALYs contraindicated?

As healthcare expenditures continue to rise, financial pressures have resulted in a desire for countries to shift resources away from traditional areas of spending. The consequent devolution and reform have resulted in increased care being provided and received within homes and communities, and in an increased reliance on unpaid caregivers. Recent empirical work indicates that costs incurred by care recipients and unpaid caregivers, including time and productivity costs, often account for significant proportions of total healthcare expenditures. However, many economic evaluations do not include these costs. Moreover, when indirect costs are assessed, the methods of valuation are inconsistent and frequently controversial. This paper provides an overview and critique of existing valuation methods. Current methods such as the human capital method, friction cost method and the Washington Panel approach are presented and critiqued according to criteria such as potential for inaccuracy, ease of application, and ethical and distributional concerns. The review illustrates the depth to which the methods have been theoretically examined, and highlights a paucity of research on costs that accrue to unpaid caregivers and a lack of research on time lost from unpaid labour and leisure. To ensure accurate and concise reporting of all time costs, it is concluded that a broad conceptual approach for time costing should be developed that draws on and then expands upon theoretical work to date.

Valuing patient and caregiver time: a review of the literature.

The Pregnancy-Unique Quantification of Emesis (PUQE) is a scoring system to quantify the severity of nausea and vomiting of pregnancy (NVP). Based on quantification of the 3 physical symptoms of NVP (nausea, vomiting and retching), PUQE closely correlates with the validated but much more complex Rhodes' score. We examined the ability of PUQE to predict four independent aspects of NVP: (a) pregnant women's ability to take multivitamins. (b) rates of emergency room visits and hospitalisation for NVP. (c) health cost of NVP. (d) women's self scores of well-being in NVP. Using large prospective cohorts of women for each end point, severity of NVP measured by PUQE had significant predictive value for all 4 aspects sought. PUQE has been validated through 4 independent clinical outcomes of direct importance and relevance for NVP. The simplicity of PUQE and the ease of its execution make it a practical tool for both clinical follow-up and research.

Wendy J. Ungar

Papers

Tenofovir and entecavir are the most effective antiviral agents for chronic hepatitis B: a systematic review and Bayesian meta-analyses

Acute appendicitis in young children: cost-effectiveness of US versus CT in diagnosis--a Markov decision analytic model.

Challenges in health state valuation in paediatric economic evaluation: are QALYs contraindicated?

Valuing patient and caregiver time: a review of the literature.

Validation studies of the Pregnancy Unique-Quantification of Emesis (PUQE) scores