In clinical settings, the absolute risk reduction due to treatment that can be expected in a particular patient is of key interest. However, logistic regression, the default regression model for... Show moreIn clinical settings, the absolute risk reduction due to treatment that can be expected in a particular patient is of key interest. However, logistic regression, the default regression model for trials with a binary outcome, produces estimates of the effect of treatment measured as a difference in log odds. We explored options to estimate treatment effects directly as a difference in risk, specifically in the network meta-analysis setting. We propose a novel Bayesian (meta-)regression model for binary outcomes on the additive risk scale. The model allows treatment effects, covariate effects, interactions and variance parameters to be estimated directly on the linear scale of clinical interest. We compared effect estimates from this model to (1) a previously proposed additive risk model by Warn, Thompson and Spiegelhalter ( "WTS model ") and (2) backtransforming the predictions from a logistic model to the natural scale after regression. The models were compared in a network meta-analysis of 20 hepatitis C trials, as well as in the analysis of simulated single trial settings. The resulting estimates diverged, in particular for small sample sizes or true risks close to 0% or 100%. Researchers should be aware that modelling untransformed risk can yield very different results from default logistic models. The treatment effect in participants with such extreme predicted risks weighed more heavily on the overall treatment effect estimate from our proposed model compared to the WTS model. In our network meta-analysis, this sensitivity of our proposed model was needed to detect all information in the data. Show less
Treatment of chronic central serous chorioretinopathy (cCSC) remains a topic of controversy. As cCSC is a disease that can wax and wane, treatment efficacy is difficult to assess especially when... Show moreTreatment of chronic central serous chorioretinopathy (cCSC) remains a topic of controversy. As cCSC is a disease that can wax and wane, treatment efficacy is difficult to assess especially when trials compare active treatments without any placebo/control group. In this study, we systematically reviewed short-term efficacies of any cCSC treatment tested in randomized controlled trials (RCT) and employed network meta-analyses to compare to non-treatment controls. We searched 11 literature databases on 20 March 2022 for RCTs of treatment of cCSC. We identified 17 RCTs including a total of 1172 eyes. Treatments included conventional laser (44 eyes), half-dose or half-fluence photodynamic therapy (PDT) (298 eyes), ranibizumab (16 eyes), antioxidants (50 eyes), mineralocorticoid receptor antagonists (187 eyes), rifampicin (91 eyes), selective retina therapy (SRT) (67 eyes) and subthreshold micropulse laser (192 eyes). Compared with controls, significant benefit on complete subretinal fluid resolution was only obtained from half-dose or half-fluence PDT (OR: 20.6; 95% CI: 6.3-66.7; p < 0.0001) and conventional laser (OR: 36.4; 95% CI: 2.0-655.7; p = 0.015), and at an order of magnitude lower degree from SRT (OR: 3.4; 95% CI: 1.7-6.8; p = 0.00075). Compared with controls and after sensitivity analyses, significant benefit in the change in best-corrected visual acuity was only obtained by half-dose/-fluence PDT (-0.13 logMAR; 95% CI: -0.20 to -0.06 logMAR; p = 0.00021). In conclusion, three treatment options provide significant improvement over no treatment: half-dose/-fluence PDT, conventional laser and to a much lesser degree SRT. Considering that conventional laser can only be applied for extrafoveal leaks, and the long-term data available for PDT-based treatments finding persisting treatment results, half-dose or half-fluence PDT is the only viable treatment option for patients with cCSC. Shortage issues with verteporfin should not lead to employment of ineffective treatment modalities, as they put patients at unnecessary risk of adverse events. Show less
OBJECTIVE: Combined oral contraceptives are often considered a treatment option for women with premenstrual syndrome or premenstrual dysphoric disorder also seeking contraception, but evidence for... Show moreOBJECTIVE: Combined oral contraceptives are often considered a treatment option for women with premenstrual syndrome or premenstrual dysphoric disorder also seeking contraception, but evidence for this treatment is scarce. We aimed to determine (1) the level of evidence for the efficacy of combined oral contraceptives in managing premenstrual depressive symptoms and overall premenstrual symptomatology and (2) the comparative efficacy of combined oral contraceptives (the International Prospective Register of Systematic Reviews registration number CRD42020205510). DATA SOURCES: We searched Cochrane Central Register of Controlled Trials, PubMed, Web of Science, PsycINFO, EMCare, and Embase from inception to June 3, 2021. STUDY ELIGIBILITY CRITERIA: All randomized clinical trials that evaluated the efficacy of combined oral contraceptives in women with premenstrual syndrome or premenstrual dysphoric disorder were considered eligible for inclusion in this meta-analysis. STUDY APPRAISAL AND SYNTHESIS METHODS: A random effect Bayesian pairwise and network meta-analysis was conducted with change in premenstrual depressive symptoms and overall premenstrual symptomatology between baseline and 3 cycles as outcome. Certainty of the evidence was assessed using the Grading of Recommendations, Assessment, Development, and Evaluation approach. RESULTS: Of 3664 records, 9 eligible trials were included that studied 1205 women with premenstrual syndrome or premenstrual dysphoric disorder (mean age per study range, 24.6-36.5 years). The pairwise meta-analysis revealed that combined oral contraceptives were more efficacious than placebo in treating overall premenstrual symptomatology (standardized mean difference, 0.41; 95% credible interval, 0.17-0.67), but not premenstrual depressive symptoms specifically (standardized mean difference, 0.22; 95% credible interval,-0.06 to 0.47). However, none of the combined oral contraceptives were more effective than each other in reducing premenstrual depressive symptoms and overall premenstrual symptomatology. CONCLUSION: Combined oral contraceptives may improve overall premenstrual symptomatology in women with premenstrual syndrome or premenstrual dysphoric disorder, but not premenstrual depressive symptoms. There is no evidence for one combined oral contraceptive being more efficacious than any other. Show less
Welch, V.A.; Hossain, A.; Ghogomu, E.; Riddle, A.; Cousens, S.; Gaffey, M.; ... ; Wells, G.A. 2019
Intestinal parasites affect millions of children globally. We aimed to assess effects of deworming children on nutritional and cognitive outcomes across potential effect modifiers using individual... Show moreIntestinal parasites affect millions of children globally. We aimed to assess effects of deworming children on nutritional and cognitive outcomes across potential effect modifiers using individual participant data (IPD). We searched multiple databases to 27 March 2018, grey literature, and other sources. We included randomised and quasi randomised trials of deworming compared to placebo or other nutritional interventions with data on baseline infection. We used a random-effects network meta-analysis with IPD and assessed overall quality, following a pre-specified protocol. We received IPD from 19 trials of STH deworming. Overall risk of bias was low. There were no statistically significant subgroup effects across age, sex, nutritional status or infection intensity for each type of STH. These analyses showed that children with moderate or heavy intensity infections, deworming for STH may increase weight gain (very low certainty). The added value of this review is an exploration of effects on growth and cognition in children with moderate to heavy infections as well as replicating prior systematic review results of small effects at the population level. Policy implications are that complementary public health strategies need to be assessed and considered to achieve growth and cognition benefits for children in helminth endemic areas. Show less
