Clinical review. Comparative effectiveness of drug treatments to prevent fragility fractures: a systematic review and network meta-analysis.

CONTEXT: Osteoporosis and osteopenia are associated with increased fracture incidence. OBJECTIVE: The aim of this study was to determine the comparative effectiveness of different pharmacological agents in reducing the risk of fragility fractures. DATA SOURCES: We searched multiple databases through 12/9/2011. STUDY SELECTION: Eligible studies were randomized controlled trials enrolling individuals at risk of developing fragility fractures and evaluating the efficacy of bisphosphonates, teriparatide, selective estrogen receptor modulators, denosumab, or calcium and vitamin D. DATA EXTRACTION: Reviewers working independently and in duplicate determined study eligibility and collected descriptive, methodological quality, and outcome data. DATA SYNTHESIS: This network meta-analysis included 116 trials (139,647 patients; median age, 64 yr; 86% females and 88% Caucasians; median follow-up, 24 months). Trials were at low to moderate risk of bias. Teriparatide had the highest risk reduction of fractures (odds ratios, 0.42, 0.30, and 0.50 for hip, vertebral, and nonvertebral fractures, respectively) and the highest probability of being ranked first for efficacy (probabilities of 42, 49, and 79% for hip, vertebral, and nonvertebral fractures, respectively). However, differences to denosumab, zoledronate, risedronate, ibandronate, and alendronate were not statistically significant. Raloxifene and bazedoxifene were likely less effective, although these data were limited. Calcium and vitamin D were ineffective given separately but reduced the risk of hip fractures if given in combination (odds ratio, 0.81; 95% confidence interval, 0.68­0.96). CONCLUSIONS: Teriparatide, bisphosphonates, and denosumab are most effective in reducing the risk of fragility fractures. Differences in efficacy across drugs are small; therefore, patients and clinicians need to consider their associated harms and costs.

Body composition and quality of life in adults treated with GH therapy: a systematic review and meta-analysis.

OBJECTIVE: To summarise the evidence about the efficacy and safety of using GH in adults with GH deficiency focusing on quality of life and body composition. DATA SOURCES: We searched MEDLINE, EMBASE, Cochrane CENTRAL, Web of Science and Scopus through April 2011. We also reviewed reference lists and contacted experts to identify candidate studies. STUDY SELECTION: Reviewers, working independently and in duplicate, selected randomised controlled trials (RCTs) that compared GH to placebo. DATA SYNTHESIS: We pooled the relative risk (RR) and weighted mean difference (WMD) by the random effects model and assessed heterogeneity using the I(2) statistic. RESULTS: Fifty-four RCTs were included enrolling over 3400 patients. The quality of the included trials was fair. GH use was associated with statistically significant reduction in weight (WMD, 95% confidence interval (95% CI): -2.31 kg, -2.66 and -1.96) and body fat content (WMD, 95% CI: -2.56 kg, -2.97 and -2.16); increase in lean body mass (WMD, 95% CI: 1.38, 1.10 and 1.65), the risk of oedema (RR, 95% CI: 6.07, 4.34 and 8.48) and joint stiffness (RR, 95% CI: 4.17, 1.4 and 12.38); without significant changes in body mass index, bone mineral density or other adverse effects. Quality of life measures improved in 11 of the 16 trials although meta-analysis was not feasible. RESULTS: GH therapy in adults with confirmed GH deficiency reduces weight and body fat, increases lean body mass and increases oedema and joint stiffness. Most trials demonstrated improvement in quality of life measures.

Clinical review: The effect of vitamin D on falls: a systematic review and meta-analysis.

CONTEXT: Vitamin D affects bone and muscle health and likely reduces the risk of falls in the elderly. OBJECTIVE: The aim of this systematic review is to summarize the existing evidence on vitamin D use and the risk of falls. DATA SOURCES: We searched electronic databases from inception through August 2010. STUDY SELECTION: Eligible studies were randomized controlled trials in which the intervention was vitamin D and the incidence of falls was reported. DATA EXTRACTION: Reviewers working in duplicate and independently extracted study characteristics, quality, and outcomes data. DATA SYNTHESIS: Odds ratio and associated 95% confidence interval were estimated from each study and pooled using the random effects model. RESULTS: We found 26 eligible trials of moderate quality that enrolled 45,782 participants, the majority of which were elderly and female. Vitamin D use was associated with statistically significant reduction in the risk of falls (odds ratio for suffering at least one fall, 0.86; 95% confidence interval, 0.77-0.96). This effect was more prominent in patients who were vitamin D deficient at baseline and in studies in which calcium was coadministered with vitamin D. The quality of evidence was low to moderate because of heterogeneity and publication bias. CONCLUSIONS: Vitamin D combined with calcium reduces the risk of falls. The reduction in studies without calcium coadministration did not reach statistical significance. The majority of the evidence is derived from trials enrolling elderly women.

Vitamin D and cardiovascular outcomes: a systematic review and meta-analysis.

CONTEXT: Several studies found association between vitamin D levels and hypertension, coronary artery calcification, and heart disease. OBJECTIVE: The aim of this study was to summarize the evidence on the effect of vitamin D on cardiovascular outcomes. DESIGN AND METHODS: We searched electronic databases from inception through August 2010 for randomized trials. Reviewers working in duplicate and independently extracted study characteristics, quality, and the outcomes of interest. Random-effects meta-analysis was used to pool the relative risks (RR) and the weighted mean differences across trials. RESULTS: We found 51 eligible trials with moderate quality. Vitamin D was associated with nonsignificant effects on the patient-important outcomes of death [RR, 0.96; 95% confidence interval (CI), 0.93, 1.00; P = 0.08], myocardial infarction (RR, 1.02; 95% CI, 0.93, 1.13; P = 0.64), and stroke (RR, 1.05; 95% CI, 0.88, 1.25; P = 0.59). These analyses were associated with minimal heterogeneity. There were no significant changes in the surrogate outcomes of lipid fractions, glucose, or diastolic or systolic blood pressure. The latter analyses were associated with significant heterogeneity, and the pooled estimates were trivial in absolute terms. CONCLUSIONS: Trial data available to date are unable to demonstrate a statistically significant reduction in mortality and cardiovascular risk associated with vitamin D. The quality of the available evidence is low to moderate at best.

Clinical review: Adult height in patients with congenital adrenal hyperplasia: a systematic review and metaanalysis.

CONTEXT: Treatment for patients with congenital adrenal hyperplasia (CAH) may affect the final height of these patients. OBJECTIVE: Our objective was to determine the distribution of achieved height in patients with classic CAH diagnosed at infancy or early childhood and treated with glucocorticoids. DATA SOURCES: We searched MEDLINE, EMBASE, Cochrane Library, ISI Web of Science, and Scopus through September 2008; the reference sections of included studies; and expert files. STUDY SELECTION: Eligible studies included patients diagnosed with CAH before age 5 and followed to final height. DATA EXTRACTION: Reviewers working in duplicate independently extracted data on study characteristics and outcomes and determined each study's risk of bias. DATA SYNTHESIS: The sd score (SDS) for final height and corrected height (defined as final height SDS - midparental height SDS) were estimated from each study and pooled using random-effects metaanalysis. The I(2) statistic was used to assess inconsistency in results across studies. RESULTS: We found 35 eligible studies, most of which were retrospective single-cohort studies. The final height SDS achieved by CAH patients was -1.38 (-1.56 to -1.20; I(2) = 90.2%), and the corrected height SDS was -1.03 (-1.20 to -0.86; I(2) = 63.1%). This was not significantly associated with age at diagnosis, gender, type and dose of steroid, and age of onset of puberty. Mineralocorticoid users had a better height outcome in comparison with the nonusers (P = 0.02). CONCLUSION: Evidence derived from observational studies suggests that the final height of CAH patients treated with glucocorticoids is lower than the population norm and is lower than expected given parental height.

Prenatal dexamethasone use for the prevention of virilization in pregnancies at risk for classical congenital adrenal hyperplasia because of 21-hydroxylase (CYP21A2) deficiency: a systematic review and meta-analyses.

CONTEXT: Prenatal treatment with dexamethasone to prevent virilization in pregnancies at risk for classical congenital adrenal hyperplasia (CAH) remains controversial. OBJECTIVE: To conduct a systematic review and meta-analyses of studies that evaluated the effects of dexamethasone administration during pregnancies at risk for classical CAH because of 21-hydroxylase deficiency (CYP21A2). DATA SOURCES: We searched MEDLINE, EMBASE, and Cochrane CENTRAL from inception through August 2009. Review of reference lists and contact with CAH experts further identified candidate studies. STUDY SELECTION: Reviewers working independently and in duplicate determined trial eligibility. Eligible studies reported the effects on either foetal or maternal outcomes of dexamethasone administered during pregnancy compared to a control group that did not receive any treatment. DATA EXTRACTION: Reviewers working independently and in duplicate determined the methodological quality of studies and collected data on patient characteristics, interventions, and outcomes. DATA SYNTHESIS: We identified only four eligible observational studies (325 pregnancies treated with dexamethasone). The methodological quality of the included studies was overall low. Meta-analysis demonstrates a reduction in foetus virilization measured by Prader score in female foetuses treated with dexamethasone initiated early during pregnancy (weighted mean difference, -2.33, 95% CI, -3.38, -1.27). No deleterious effects of dexamethasone on stillbirths, spontaneous abortions, foetal malformations, neuropsychological or developmental outcomes were found although these data are quite sparse. There was increased oedema and striae in the mothers treated with dexamethasone. There were no data on long-term follow-up of physical and metabolic outcomes in children exposed to dexamethasone. CONCLUSIONS: The observational nature of the available evidence and the overall small sample size of the whole body of the literature significantly weaken inferences about the benefits and harms of dexamethasone in this setting. Dexamethasone seems to be associated with reduction in foetus virilization without significant maternal or foetal adverse effects. However, this review underscores the current uncertainty and further investigation is clearly needed. The decision about initiating treatment should be based on patients' values and preferences and requires fully informed and consenting parents.

Stopping randomized trials early for benefit and estimation of treatment effects: systematic review and meta-regression analysis.

CONTEXT: Theory and simulation suggest that randomized controlled trials (RCTs) stopped early for benefit (truncated RCTs) systematically overestimate treatment effects for the outcome that precipitated early stopping. OBJECTIVE: To compare the treatment effect from truncated RCTs with that from meta-analyses of RCTs addressing the same question but not stopped early (nontruncated RCTs) and to explore factors associated with overestimates of effect. DATA SOURCES: Search of MEDLINE, EMBASE, Current Contents, and full-text journal content databases to identify truncated RCTs up to January 2007; search of MEDLINE, Cochrane Database of Systematic Reviews, and Database of Abstracts of Reviews of Effects to identify systematic reviews from which individual RCTs were extracted up to January 2008. STUDY SELECTION: Selected studies were RCTs reported as having stopped early for benefit and matching nontruncated RCTs from systematic reviews. Independent reviewers with medical content expertise, working blinded to trial results, judged the eligibility of the nontruncated RCTs based on their similarity to the truncated RCTs. DATA EXTRACTION: Reviewers with methodological expertise conducted data extraction independently. RESULTS: The analysis included 91 truncated RCTs asking 63 different questions and 424 matching nontruncated RCTs. The pooled ratio of relative risks in truncated RCTs vs matching nontruncated RCTs was 0.71 (95% confidence interval, 0.65-0.77). This difference was independent of the presence of a statistical stopping rule and the methodological quality of the studies as assessed by allocation concealment and blinding. Large differences in treatment effect size between truncated and nontruncated RCTs (ratio of relative risks <0.75) occurred with truncated RCTs having fewer than 500 events. In 39 of the 63 questions (62%), the pooled effects of the nontruncated RCTs failed to demonstrate significant benefit. CONCLUSIONS: Truncated RCTs were associated with greater effect sizes than RCTs not stopped early. This difference was independent of the presence of statistical stopping rules and was greatest in smaller studies.

Stopping randomized trials early for benefit: a protocol of the Study Of Trial Policy Of Interim Truncation-2 (STOPIT-2).

BACKGROUND: Randomized clinical trials (RCTs) stopped early for benefit often receive great attention and affect clinical practice, but pose interpretational challenges for clinicians, researchers, and policy makers. Because the decision to stop the trial may arise from catching the treatment effect at a random high, truncated RCTs (tRCTs) may overestimate the true treatment effect. The Study Of Trial Policy Of Interim Truncation (STOPIT-1), which systematically reviewed the epidemiology and reporting quality of tRCTs, found that such trials are becoming more common, but that reporting of stopping rules and decisions were often deficient. Most importantly, treatment effects were often implausibly large and inversely related to the number of the events accrued. The aim of STOPIT-2 is to determine the magnitude and determinants of possible bias introduced by stopping RCTs early for benefit. METHODS/DESIGN: We will use sensitive strategies to search for systematic reviews addressing the same clinical question as each of the tRCTs identified in STOPIT-1 and in a subsequent literature search. We will check all RCTs included in each systematic review to determine their similarity to the index tRCT in terms of participants, interventions, and outcome definition, and conduct new meta-analyses addressing the outcome that led to early termination of the tRCT. For each pair of tRCT and systematic review of corresponding non-tRCTs we will estimate the ratio of relative risks, and hence estimate the degree of bias. We will use hierarchical multivariable regression to determine the factors associated with the magnitude of this ratio. Factors explored will include the presence and quality of a stopping rule, the methodological quality of the trials, and the number of total events that had occurred at the time of truncation.Finally, we will evaluate whether Bayesian methods using conservative informative priors to "regress to the mean" overoptimistic tRCTs can correct observed biases. DISCUSSION: A better understanding of the extent to which tRCTs exaggerate treatment effects and of the factors associated with the magnitude of this bias can optimize trial design and data monitoring charters, and may aid in the interpretation of the results from trials stopped early for benefit.