A threshold analysis assessed the credibility of conclusions from network meta-analysis

Objective: To assess the reliability of treatment recommendations based on network meta-analysis (NMA)Study design: We consider evidence in an NMA to be potentially biased. Taking each pair-wise contrast in turn we use a structured series of threshold analyses to ask: (a) “How large would the bias in this evidence-base have to be before it changed our decision?” and (b) “If the decision changed, what is the new recommendation?” We illustrate the method via two NMAs in which a GRADE assessment for NMAs has been implemented: weight-loss and osteoporosis.Results. Four of the weight-loss NMA estimates were assessed as “low” and 6 as “moderate” quality by GRADE; for osteoporosis 6 were “low”, 9 “moderate” and 1 “high”. The threshold analysis suggests plausible bias in 3 of 10 estimates in the weight-loss network could have changed the treatment recommendation. For osteoporosis plausible bias in 6 of 16 estimates could change the recommendation. There was no relation between plausible bias changing a treatment recommendation and the original GRADE assessments.Conclusions. Reliability judgements on individual NMA contrasts do not help decision makers understand whether a treatment recommendation is reliable. Threshold analysis reveals whether the final recommendation is robust against plausible degrees of bias in the data

Network meta-analysis with competing risk outcomes

AbstractBackgroundCost-effectiveness analysis often requires information on the effectiveness of interventions on multiple outcomes, and commonly these take the form of competing risks. Nevertheless, methods for synthesis of randomized controlled trials with competing risk outcomes are limited.ObjectiveThe aim of this study was to develop and illustrate flexible evidence synthesis methods for trials reporting competing risk results, which allow for studies with different follow-up times, and that take account of the statistical dependencies between outcomes, regardless of the number of outcomes and treatments.MethodsWe propose a competing risk meta-analysis based on hazards, rather than probabilities, estimated in a Bayesian Markov chain Monte Carlo (MCMC) framework using WinBUGS software. Our approach builds on existing work on mixed treatment comparison (network) meta-analysis, which can be applied to any number of treatments, and any number of competing outcomes, and to data sets with varying follow-up times. We show how a fixed effect model can be estimated, and two random treatment effect models with alternative structures for between-trial variation. We suggest methods for choosing between these alternative models.ResultsWe illustrate the methods by applying them to a data set involving 17 trials comparing nine antipsychotic treatments for schizophrenia including placebo, on three competing outcomes: relapse, discontinuation because of intolerable side effects, and discontinuation for other reasons.ConclusionsBayesian MCMC provides a flexible framework for synthesis of competing risk outcomes with multiple treatments, particularly suitable for embedding within probabilistic cost-effectiveness analysis

Young women's continued use of oral contraceptives over other hormonal methods: findings from a qualitative study

Background Long-acting reversible contraceptives (LARC) have become more commonly promoted in the UK, but most young women still rely on the contraceptive pill. Here, we describe young women's accounts of hormonal contraceptive use to explore why this might be the case. Methods In-depth interviews with twenty 20-year-old women from eastern Scotland in the UK. Results All but one woman reported use of the pill. It was the method they expected to use, sought out, and received. Belief in the pill's efficacy was maintained even when knowledge or experience of failure suggested otherwise. Only four women reported using alternative hormonal methods and only did so after experiencing unmanageable problems with the pill (side effects or forgetting to take it). All then discontinued use because of weight gain or dislike of menstrual suppression. Conclusions Attempts to promote LARC must address these issues. Pill use can be unproblematic if managed well, and should continue to be promoted as an appropriate contraceptive for young women

Cross-border flows of students for higher education: Push–pull factors and motivations of mainland Chinese students in Hong Kong and Macau

Within the context of broad literature on cross-border flows for higher education, this article examines the distinctive case of mainland Chinese students in Hong Kong and Macau. These territories are a sort of bridge between the fully domestic and the fully international. Hong Kong and Macau higher education plays a dual role, as a destination in itself for higher education and as a stepping-stone for students' further international development. Patterns in Hong Kong are slightly different from those in Macau, and the territories may thus be usefully compared with each other as well as taken as a pair for comparison with other parts of the world. The paper begins by noting the literature on the ways that push and pull factors influence student mobility, and then turns to motivations in pursuit of academic and professional growth, economic benefit, individual internationalisation, and enhanced social status. The paper shows that flows of mainland Chinese students are driven by both excess and differentiated demand. Analysis of the distinctive features of this pair of territories adds to wider conceptual understanding of the nature of cross-border flows for higher education. © Springer Science+Business Media B.V. 2007.link_to_subscribed_fulltex