Despite this biological logic, the clinical evidence base for interventions that target mitochondria in older people with type 2 diabetes remains scattered and difficult to interpret. Hundreds of trials have tested drugs, supplements, and lifestyle programs that plausibly act on mitochondrial pathways, but few studies have focused specifically on adults aged 60 and above, and almost none have compared these interventions against one another in a rigorous, quantitative way. A research team led by Hao Liu, Aochuan Sun, Yu Deng, Yihan Li, Jiayu Hu, and Zhengtang Liu now aims to change that. Their protocol, published in PLOS One, lays out a systematic review with a conditional network meta-analysis designed to map and rank the comparative efficacy and safety of mitochondrial-targeting interventions in this underexplored population.

The scope of the planned review is deliberately broad. The researchers define interventions with mitochondrial effects in two ways: either the intervention’s primary mechanism of action is known to target mitochondrial pathways, or the intervention has been explicitly evaluated in trials for its effects on direct markers of mitochondrial function. This umbrella captures pharmacological agents, nutritional supplements, and lifestyle modifications, all of which will be compared against placebo, standard care, or no intervention at all. By casting a wide net, the team hopes to assemble a comprehensive picture of how different therapeutic strategies, from common medications to exercise regimens, influence the cellular machinery that governs energy metabolism in aging bodies.

The primary endpoint of the review is mitochondrial function itself, measured through biomarkers that will be categorized by biological domain, tissue source, and assay method. This classification matters because mitochondrial health can be assessed in strikingly different ways: some studies measure respiratory chain activity in muscle biopsies, others track circulating markers of mitochondrial damage, and still others rely on indirect proxies. By organizing outcomes according to where and how they were measured, the researchers aim to bring analytical order to a heterogeneous literature. Secondary outcomes extend into clinically familiar territory, including glycated hemoglobin, fasting plasma glucose, fasting insulin, the homeostatic model assessment of insulin resistance, body weight, and body mass index, alongside broader measures of geriatric health and safety.

Methodologically, the protocol follows the highest current standards for evidence synthesis. It was prepared in accordance with the PRISMA-P reporting guideline for protocols and will adhere to PRISMA 2020 and, where applicable, the PRISMA-NMA extension for network meta-analyses. The review is registered with PROSPERO under identifier CRD420251145356, a step that guards against selective reporting and undisclosed changes of plan. The search strategy spans five major databases, PubMed, Embase, the Cochrane Central Register of Controlled Trials, Web of Science, and Scopus, covering the literature from inception to April 2026. Search terms focus on type 2 diabetes, mitochondrial function and dysfunction, and interventions, with age eligibility assessed during full-text screening.

Age criteria receive careful treatment because many diabetes trials enroll broad adult populations without reporting age-specific results. The primary analysis will include trials whose participants are aged 60 or older, or trials from which data for this age group can be extracted. As a sensitivity analysis, the team will also examine studies with a mean or median participant age of at least 60, allowing them to test whether conclusions hold under a slightly looser definition of the target population. Throughout the review, two independent reviewers will handle study screening, data extraction, and risk-of-bias assessment using the Cochrane RoB 2 tool, a structured instrument for evaluating the reliability of randomized trial results.

The analytical centerpiece, the network meta-analysis, represents a statistical advance over traditional pairwise comparisons. Conventional meta-analyses can only pool trials that compare the same two interventions directly, leaving many treatments unconnected. A network meta-analysis instead weaves together direct and indirect evidence across an entire network of trials, enabling simultaneous comparison and ranking of many interventions even when some have never been tested head to head. Crucially, the team has built a conditional into their design: the network meta-analysis will proceed only if the evidence network is sufficiently connected and clinically coherent. If those conditions are not met, the researchers will fall back on pairwise meta-analysis or a structured narrative synthesis, ensuring that statistical ambition never outruns the underlying data.

Heterogeneity, the variability among trial results that can arise from differences in populations, interventions, and measurement methods, poses a well-known threat to any pooled analysis. The protocol addresses it on several fronts. Random-effects models will be employed throughout, acknowledging that true effects may vary across studies. Prespecified subgroup analyses and meta-regression will explore potential sources of heterogeneity, such as intervention duration and baseline glycated hemoglobin levels. If significant heterogeneity persists even after these efforts, the team will apply the Synthesis Without Meta-analysis framework, a formal approach for narrative review that avoids forcing incompatible results into a single statistical estimate. Finally, the certainty of the evidence will be appraised using the GRADE system and the CINeMA tool, both of which grade how much confidence readers can place in each conclusion.

The ethical footprint of the project is minimal by design, since the review will rely exclusively on previously anonymized data from primary studies, and the findings are intended for publication in a peer-reviewed journal. Yet the potential implications extend well beyond academic bookkeeping. If the network meta-analysis succeeds in ranking mitochondrial interventions by efficacy and safety, clinicians caring for older adults with type 2 diabetes could gain an evidence-based hierarchy of options, from pharmacological agents to nutritional supplements to lifestyle changes, each anchored to measurable effects on cellular energy metabolism. For a population in which diabetes complications, frailty, and polypharmacy intersect, such clarity could translate into more precise and personalized treatment decisions.

The study also highlights a broader shift in diabetes research: the recognition that aging and metabolism are intertwined at the subcellular level. As the global population of older adults with type 2 diabetes continues to grow, interventions that restore mitochondrial function may offer benefits that conventional glucose-lowering drugs alone cannot capture, potentially affecting fatigue, physical function, and the trajectory of diabetic complications. Whether any specific intervention will emerge as a clear frontrunner remains to be seen, and the conditional design of the planned analysis reflects an appropriate scientific caution. What is already clear is that the era of treating diabetes without reference to the cell’s power stations is drawing to a close, and rigorous, age-focused evidence synthesis is the tool that will determine which mitochondrial strategies deserve a place in clinical practice.

Subject of Research: Systematic review and network meta-analysis protocol evaluating mitochondrial-targeting interventions for older adults with type 2 diabetes

Article Title: Interventions with mitochondrial-related effects in older adults with type 2 diabetes: Protocol for a systematic review with conditional network meta-analysis

Article References: Liu, H., Sun, A., Deng, Y., Li, Y., Hu, J., & Liu, Z. (2026). Interventions with mitochondrial-related effects in older adults with type 2 diabetes: Protocol for a systematic review with conditional network meta-analysis. PLOS One, 21(10), e0360683. https://doi.org/10.1371/journal.pone.0360683

Image Credits: AI Generated

DOI: 10.1371/journal.pone.0360683

Keywords: mitochondria, type 2 diabetes, older adults, network meta-analysis, systematic review, insulin resistance, mitochondrial dysfunction, glycemic control, PRISMA, PROSPERO, evidence synthesis, biomarkers