BackgroundExercise has been shown to be effective in treating depression, but trials testing the effect of exercise for depressed adolescents utilising mental health services are rare. The aim of this study was to determine the effectiveness of a preferred intensity exercise intervention on the depressive symptoms of adolescents with depression.MethodsWe randomly assigned 87 adolescents who were receiving treatment for depression to either 12 sessions of aerobic exercise at preferred intensity alongside treatment as usual or treatment as usual only. The primary outcome was depressive symptom change using the Children’s Depression Inventory 2nd Version (CDI-2) at post intervention. Secondary outcomes were health-related quality of life and physical activity rates. Outcomes were taken at baseline, post intervention and at six month follow up.ResultsCDI-2 score reduction did not differ significantly between groups at post-intervention (est. 95 % CI −6.82, 1.68, p = 0.23). However, there was a difference in CDI-2 score reduction at six month follow-up in favour of the intervention of −4.81 (est. 95 % CI −9.49, −0.12, p = 0.03). Health-related quality of life and physical activity rates did not differ significantly between groups at post-intervention and follow-up.ConclusionsThere was no additional effect of preferred intensity exercise alongside treatment as usual on depressive reduction immediately post intervention. However, effects were observed at six months post-intervention, suggesting a delayed response. However, further trials, with larger samples are required to determine the validity of this finding.Trial registrationClinicalTrials.gov NCT01474837, March 16 2011
ObjectivesIndividual participant data (IPD) meta-analyses often analyze their IPD as if coming from a single study. We compare this approach with analyses that rather account for clustering of patients within studies.Study Design and SettingComparison of effect estimates from logistic regression models in real and simulated examples.ResultsThe estimated prognostic effect of age in patients with traumatic brain injury is similar, regardless of whether clustering is accounted for. However, a family history of thrombophilia is found to be a diagnostic marker of deep vein thrombosis [odds ratio, 1.30; 95% confidence interval (CI): 1.00, 1.70; P = 0.05] when clustering is accounted for but not when it is ignored (odds ratio, 1.06; 95% CI: 0.83, 1.37; P = 0.64). Similarly, the treatment effect of nicotine gum on smoking cessation is severely attenuated when clustering is ignored (odds ratio, 1.40; 95% CI: 1.02, 1.92) rather than accounted for (odds ratio, 1.80; 95% CI: 1.29, 2.52). Simulations show models accounting for clustering perform consistently well, but downwardly biased effect estimates and low coverage can occur when ignoring clustering.ConclusionResearchers must routinely account for clustering in IPD meta-analyses; otherwise, misleading effect estimates and conclusions may arise.
Hierarchical models such as the bivariate and hierarchical summary receiver operating characteristic (HSROC) models are recommended for meta-analysis of test accuracy studies. These models are challenging to fit when there are few studies and/or sparse data (for example zero cells in contingency tables due to studies reporting 100% sensitivity or specificity); the models may not converge, or give unreliable parameter estimates. Using simulation, we investigated the performance of seven hierarchical models incorporating increasing simplifications in scenarios designed to replicate realistic situations for meta-analysis of test accuracy studies. Performance of the models was assessed in terms of estimability (percentage of meta-analyses that successfully converged and percentage where the between study correlation was estimable), bias, mean square error and coverage of the 95% confidence intervals. Our results indicate that simpler hierarchical models are valid in situations with few studies or sparse data. For synthesis of sensitivity and specificity, univariate random effects logistic regression models are appropriate when a bivariate model cannot be fitted. Alternatively, an HSROC model that assumes a symmetric SROC curve (by excluding the shape parameter) can be used if the HSROC model is the chosen meta-analytic approach. In the absence of heterogeneity, fixed effect equivalent of the models can be applied.
Test strategies that combine ultrasound markers with serum markers, especially PAPP-A and free ßhCG, and maternal age were significantly better than those involving only ultrasound markers (with or without maternal age) except nasal bone. They detect about nine out of 10 Down's affected pregnancies for a fixed 5% FPR. Although the absence of nasal bone appeared to have a high diagnostic accuracy, only five out of 10 affected Down's pregnancies were detected at a 1% FPR.
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