Family-based interventions for glycemic control and psychosocial outcomes in adolescents with type 1 diabetes: a systematic review and meta-analysis

Adolescents with type 1 diabetes mellitus (T1DM) face substantial challenges in diabetes management due to developmental, behavioral, and psychosocial factors. Family involvement plays an important role in adolescent diabetes care, yet evidence regarding the effects of family-based interventions on glycemic control, self-management, and psychosocial outcomes remains inconsistent. This systematic review and meta-analysis aimed to evaluate these effects in adolescents with T1DM. We searched nine databases from inception to September 29, 2026, for randomized controlled trials comparing family-based interventions with usual care, routine education, or waiting-list controls. The primary outcome was glycated hemoglobin (HbA1c); secondary outcomes included blood glucose monitoring frequency, self-management adherence, quality of life, diabetes-related distress, family conflict, and self-efficacy. Pooled effects were estimated using random-effects models. Risk of bias was assessed using RoB 2, including an HbA1c-specific assessment, and certainty of evidence was evaluated using GRADE. Nineteen randomized controlled trials involving 2,054 adolescents were included. In the study-level assessment, 13 trials were rated as having some concerns and six as high risk of bias; the HbA1c-specific assessment identified four trials at low risk, 11 with some concerns, and two at high risk. Compared with control conditions, family-based interventions were associated with a modest reduction in HbA1c (MD = − 0.31%, 95% CI [− 0.55, − 0.07]; P = 0.01), together with improvements in self-management adherence (SMD = 0.19, 95% CI [0.01, 0.37]; P = 0.04), quality of life (SMD = 0.30, 95% CI [0.15, 0.46]; P < 0.001), blood glucose monitoring frequency (MD = 0.77 checks/day, 95% CI [0.23, 1.30]; P = 0.005), and family conflict (SMD = − 0.31, 95% CI [− 0.57, − 0.05]; P = 0.02). No clear effect was found for diabetes-related distress, and evidence for self-efficacy was limited and inconsistent. Neither the prespecified analysis by follow-up duration nor the post hoc analyses by baseline HbA1c and intervention components showed statistically significant between-subgroup differences. Certainty of evidence ranged from moderate to very low: moderate for quality of life, low for self-management adherence and diabetes-related distress, and very low for HbA1c, blood glucose monitoring frequency, and family conflict. Family-based interventions were associated with modest improvements in HbA1c, self-management adherence, blood glucose monitoring frequency, family conflict, and quality of life among adolescents with T1DM, supporting their potential role as part of comprehensive diabetes care. However, the certainty of evidence was limited, and exploratory subgroup analyses did not establish which adolescents were most likely to benefit or whether any intervention component was superior. Larger, well-designed randomized controlled trials with longer follow-up, prespecified component comparisons, and standardized outcome measures are needed to determine the long-term effects of these interventions and identify the populations most likely to benefit. PROSPERO CRD420251252169. Registered on 11 December 2025.