Reporting quality of randomized controlled trials examining nutritional interventions in mild cognitive impairment

Nutritional strategies are increasingly recognized as critical interventions for preventing or delaying the progression of Mild Cognitive Impairment (MCI) to dementia. While the randomized controlled trial (RCT) is considered the gold standard for evaluating healthcare interventions, nutrition-related trials in MCI populations are susceptible to specific methodological biases. Adequate reporting of these methodological domains is critical for assessing internal validity and reproducibility.

We conducted a cross-sectional survey of English-language RCTs and systematically searched PubMed, EMBASE, and Web of Science from inception to March 15, 2025, with an updated search in August 2025. Reporting quality was evaluated using a modified composite checklist comprising 37 items from the CONSORT 2010 Statement and selected candidate items proposed for the nutritional extension (draft recommendations). We calculated an overall adherence score and performed multivariable linear regression to identify study characteristics associated with reporting quality.

A total of 75 trials were included. The mean overall adherence score was 20.4 (SD 5.2). While reporting of eligibility criteria (n = 71, 94.7%) and baseline characteristics (n = 72, 96.0%) was adequate, critical methodological domains were frequently under-reported. Only 25 trials (33.3%) described allocation concealment, 34 (45.3%) detailed blinding procedures, and 8 (10.7%) provided sufficient details on trial implementation. Notably, despite the target population, less than half of the trials (n = 32, 42.7%) reported data on intervention adherence or acceptability, and only 10 trials (13.3%) explicitly distinguished between statistical significance and clinical relevance. Multivariable analysis indicated that publication year (>2020), trial registration, and protocol availability were independently associated with higher reporting scores.

Reporting quality in nutritional trials for MCI remains suboptimal, particularly in domains essential for interpreting trial validity, such as randomization, blinding, and adherence verification. The frequent omission of these details limits the ability to distinguish intervention effects from placebo responses or poor compliance. Rigorous adherence to comprehensive reporting standards, including the forthcoming CONSORT extension for nutrition, is necessary to improve the reliability and reproducibility of evidence in this field.