Comparative effectiveness of non-pharmacological interventions for older adults with oral frailty: a systematic review and network meta-analysis

BACKGROUND: Oral frailty is an emerging frailty phenotype that adversely affects older adults' quality of life and overall health outcomes. Although non-pharmacological interventions have shown potential benefits in managing oral frailty, their comparative effectiveness remains unclear. OBJECTIVE: To evaluate and compare the effectiveness of different non-pharmacological interventions for the management of oral frailty in older adults. METHODS: Electronic databases, including MEDLINE, EMBASE, CENTRAL, CNKI, and Wanfang, as well as the clinical trial registry ClinicalTrials.gov, were systematically searched from inception to October 2024 to identify eligible randomized controlled trials (RCTs). Study selection and data extraction were independently conducted by two reviewers. Methodological quality was assessed using the Revised Cochrane Risk of Bias Tool for Randomized Trials (RoB 2). The certainty of the evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach for network meta-analysis. Mean difference (MD) and confidence interval (CI) were estimated using a random-effects network meta-analysis within a frequentist framework. RESULTS: Twenty-six studies met the inclusion criteria, of which 18 provided sufficient data for inclusion in the network meta-analysis. Twelve RCTs involving 1,094 participants reported changes in tongue pressure from baseline to endpoint. Compared with control, e-health programmes [MD = 6.66, 95% CI (3.08, 10.24)], comprehensive training [MD = 5.57, 95% CI (2.62, 8.52)], and tongue resistance exercise [MD = 3.90, 95% CI (0.73, 7.07)] significantly improved tongue pressure. Ten RCTs involving 888 participants reported bite force outcomes, with chewing exercise demonstrating superior effectiveness compared with control [MD = 81.87, 95% CI (19.46, 144.29)]. Seven RCTs involving 666 participants reported salivary flow rate outcomes. E-health programmes [MD = 0.50, 95% CI (0.03, 0.97)], tongue resistance exercise [MD = 0.26, 95% CI (0.06, 0.46)], swallowing exercise [MD = 0.16, 95% CI (0.07, 0.25)], and comprehensive training [MD = 0.12, 95% CI (0.05, 0.18)] were associated with improvements in salivary flow rate. CONCLUSIONS: E-health programmes integrating remote supervision with oral health education and exercise training demonstrated the greatest improvements in tongue pressure and salivary flow rate, whereas chewing-based exercise produced the largest improvement in bite force. However, given that the current evidence is largely derived from studies with small sample sizes and short follow-up periods, these findings should be interpreted with caution. Using the GRADE approach, the certainty of evidence was rated as moderate only for comprehensive training with respect to tongue pressure and salivary flow rate, whereas the certainty of evidence for all other comparisons, including those involving e-health interventions, ranged from low to very low. Consequently, these findings should be interpreted with caution and require confirmation in larger, high-quality randomized controlled trials. Geriatric practice should prioritize symptom-targeted interventions to improve treatment effectiveness, rather than adopting a uniform approach. TRIAL REGISTRATION: The study protocol was prospectively registered on PROSPERO (CRD42024593211).