Evidence-based sample size estimation based upon an updated meta-regression analysis

Optimal dose and duration of iron supplementation for treating iron deficiency anaemia in children and adolescents: A systematic review and meta-analysis

INTRODUCTION

Iron deficiency anaemia (IDA) accounts for nearly two-thirds of all anaemia cases globally. Despite the widespread use of iron supplementation, the optimal dose and duration for treating IDA remain unclear. In this study, we aimed to determine the most effective dose and duration of iron supplementation for improving haemoglobin (Hb) levels in children and adolescents (≤19 years) with IDA.

METHODS

A systematic review and meta-analysis were conducted. We searched MEDLINE, Embase, CINAHL, and the Cochrane Library for peer-reviewed studies published between 2013 and 2024. The interventions included iron supplementation with a defined dose and duration of at least 30 days. Comparators were placebo, no treatment, or alternative regimens. The outcome was the change in Hb levels. Eligible studies included IDA cases diagnosed through ferritin level measurements in healthy individuals. Studies involving pregnant women or children with underlying conditions were excluded. A meta-analysis was performed using standardized mean differences to pool effect sizes for Hb improvement with 95% confidence intervals (CIs). Subgroup analyses were performed for different treatment durations (<3 months, 3-6 months, >6 months) and dosage categories (<5 mg/kg/day, 5-10 mg/kg/day, >10 mg/kg/day). A random-effects meta-regression model was used to determine the optimal dose and duration, accounting for known covariates affecting Hb improvement.

RESULTS

A total of 28 studies with 8,829 participants from 16 countries were included. The pooled effect size for Hb improvement was 2.01 gm/dL (95% CI: 1.48-2.54, p < 0.001). Iron supplementation for less than 3 months showed the highest significant effect size (2.39 gm/dL, 95% CI: 0.72-4.07), followed by treatments exceeding 6 months (1.93 gm/dL, 95% CI: 0.09-3.77). The lowest effect size was observed in treatments lasting 3-6 months (1.58 gm/dL, 95% CI: 0.93-2.23). Low-dose iron supplementation (<5 mg/kg/day) demonstrated favourable trends in Hb improvement, particularly in individuals with lower baseline Hb levels. Oral ferrous sulphate had a significant effect (2.03 gm/dL, 95% CI: 1.24-2.82), while parenteral ferric Carboxymaltose showed consistent efficacy.

CONCLUSION

Low-dose iron supplementation (<5 mg/kg/day) combined with treatment durations of either less than 3 months or more than 6 months, is optimal for improving Hb levels in children and adolescents with IDA. Tailoring treatment based on baseline Hb levels and anaemia severity is essential. These findings provide evidence to support updated guidelines on iron supplementation in paediatric and adolescent populations and inform national anaemia management programmes.

TRIAL REGISTRATION

Prospero registration number: This study was registered with PROSPERO (CRD42024541773).

Bone mineral density and vertebral fractures in patients with systemic lupus erythematosus: A systematic review and meta-regression

Background

Observational studies have indicated a high but heterogeneous prevalence of low bone mineral density (BMD) and vertebral fractures (VF) in patients with systemic lupus erythematosus (SLE). Therefore, the objectives of this systematic review and meta-regression were: 1) to compare BMD between SLE patients and healthy controls and 2) to evaluate the relationship between BMD and glucocorticoid therapy and VF in SLE patients.

Methods and findings

Articles were identified from electronic databases (PubMed, Embase, VHL, SciELO and the Cochrane Library). Prospective longitudinal and cross-sectional studies were considered for review. We evaluated the quality of the evidence included using the Oxford Centre for evidence-based medicine (EBM) Levels of Evidence. In total, 38 articles were identified and analyzed (3442 SLE cases and 6198 controls) in the analysis of BMD (9232 women and 408 men). There were significant differences in mean BMD between SLE patients and controls. BMD mean difference in cases/controls: -0.0566 95% CI (-0.071, -0.0439; p = < 0.0001). When only SLE patients were analyzed, the BMD did not significantly differ between patients who had or had not received glucocorticoid (GCT) therapy. 694 SLE patients were included in the analysis of VF (189 with VF vs. 505 without VF). Patients with VF had lower BMD than patients without VF (BMD mean difference without VF/with VF: 0.033 (95%CI: 0.006–0.060); p-value: 0.0156).

Conclusions

Patients with SLE had lower BMD than healthy controls. Moreover, SLE patients with VF had lower BMD than patients without VF. However, our data did not show that GCT therapy had an impact on BMD.

Association between IGF2BP2 Polymorphisms and Type 2 Diabetes Mellitus: A Case-Control Study and Meta-Analysis

Background: Genome-wide association studies (GWAS) found that IGF2BP2 rs4402960 and rs1470579 polymorphisms were associated with type 2 diabetes mellitus (T2DM) risk. Many studies have replicated this association, but yielded inconsistent results. Materials and Methods: A case-control study consisting of 461 T2DM patients and 434 health controls was conducted to detect the genetic susceptibility of IGF2BP2 in a northern Han Chinese population. A meta-analysis was to evaluate the association more precisely in Asians. Results: In the case-control study, the carriers of TT genotype at rs4402960 had a higher T2DM risk than the G carriers (TG + GG) (adjusted odd ratio (AOR) = 1.962, 95% confidence interval (95% CI) = 1.065–3.612, p = 0.031]; CC carriers at rs1470579 were more susceptible to T2DM than A carriers (CA + AA) (AOR = 2.014, 95% CI = 1.114–3.642, p = 0.021). The meta-analysis containing 36 studies demonstrated that the two polymorphisms were associated with T2DM under the allele comparison, genetic models of dominant and recessive in Asians (p < 0.05). The rs4402960 polymorphisms were significantly associated with the T2DM risk after stratification by diagnostic criterion, size of sample and average age and BMI of cases, while there’re no consistent results for rs1470579. Conclusions: Our data suggests that IGF2BP2 polymorphisms are associated with T2DM in Asian populations.

Bayesian sequential meta-analysis design in evaluating cardiovascular risk in a new antidiabetic drug development program

Recently, the Center for Drug Evaluation and Research at the Food and Drug Administration released a guidance that makes recommendations about how to demonstrate that a new antidiabetic therapy to treat type 2 diabetes is not associated with an unacceptable increase in cardiovascular risk. One of the recommendations from the guidance is that phases II and III trials should be appropriately designed and conducted so that a meta-analysis can be performed. In addition, the guidance implies that a sequential meta-analysis strategy could be adopted. That is, the initial meta-analysis could aim at demonstrating the upper bound of a 95% confidence interval (CI) for the estimated hazard ratio to be < 1.8 for the purpose of enabling a new drug application or a biologics license application. Subsequently after the marketing authorization, a final meta-analysis would need to show the upper bound to be < 1.3. In this context, we develop a new Bayesian sequential meta-analysis approach using survival regression models to assess whether the size of a clinical development program is adequate to evaluate a particular safety endpoint. We propose a Bayesian sample size determination methodology for sequential meta-analysis clinical trial design with a focus on controlling the familywise type I error rate and power. We use the partial borrowing power prior to incorporate the historical survival meta-data into the Bayesian design. We examine various properties of the proposed methodology, and simulation-based computational algorithms are developed to generate predictive data at various interim analyses, sample from the posterior distributions, and compute various quantities such as the power and the type I error in the Bayesian sequential meta-analysis trial design. We apply the proposed methodology to the design of a hypothetical antidiabetic drug development program for evaluating cardiovascular risk.