A Systematic Literature Review of Randomized Controlled Trials to Prevent Type 2 Diabetes: Comparison of In-Person and Digital Interventions (Preprint)
Authors: Riera-Serra Pau , Morales Hernández David , Gonçalves Bradley Daniela , Fiol-deRoque Maria Antònia , Zamanillo-Campos Rocío , Ricci-Cabello Ignacio 
Published: February 2025

BACKGROUND

Digital lifestyle interventions to prevent type 2 diabetes mellitus (T2DM) have become more common in the past decade, particularly in the United States. However, how their effectiveness compares with interventions delivered in-person remains unclear, partly due to variability in study design, including format and content of the intervention. Understanding the relative impact of these two modalities is critical for informing evidence-based implementation of lifestyle interventions to prevent T2DM in diverse healthcare settings.

OBJECTIVE

To compare the effectiveness of digital versus in-person interventions for preventing T2DM.

METHODS

Following Cochrane methodology, a systematic literature review was conducted to identify and synthesize evidence from randomized controlled trials (RCTs). Searches were conducted in EMBASE, MEDLINE, and Cochrane CENTRAL from inception to December 2024. Completed and ongoing RCTs were eligible. There were no language restrictions to the searches, but to be included studies had to be published in English or Spanish. Studies comparing digital and in-person interventions were eligible. Outcomes for inclusion were selected based on a stakeholder consultation, and were classified as critical (such as body mass index and quality of life) or important (namely physical activity level, incidence of T2DM, and cost-effectiveness). Meta-analyses were performed where appropriate, and narrative syntheses were provided for the remaining outcomes. The GRADE approach was used to assess the certainty of evidence.

RESULTS

Eight RCTs met the inclusion criteria, including six completed trials with published results and two ongoing trials. The completed trials encompassed a total of 2,450 participants across various healthcare settings. There was considerable methodological variation across trials, which included the format and content of the interventions, the setting where they were delivered and the outcomes definition.
At 12 months, digital interventions were associated with significantly greater weight loss than in-person interventions (n= 1459 participants, mean difference: –1.38 kg, 95% confidence interval [CI] –2.34 to –0.43), with moderate certainty of evidence. At shorter (3 and 6 months) and longer (15-18 months) time points, no relevant differences were observed for weight, body mass index, or glycosylated hemoglobin levels between the modalities, with the certainty of evidence rated as very low to low. Evidence about cost-effectiveness was scarce. No trials evaluated key outcomes such as quality of life or incidence of T2DM. For adverse events, no significant differences were found between modalities (incidence risk ratio: 1.06, 95% CI: 0.45 to 2.50).

CONCLUSIONS

This systematic literature review highlights that while digital and in-person interventions can both be effective for T2DM prevention, their relative benefits are still unclear. The limited certainty of evidence and the dearth of critical outcomes, such as T2DM incidence, underscore the need for further well-designed RCTs. Future research should prioritize equivalence in intervention intensity, longer follow-up durations, and standardized reporting of outcomes to better inform public health decision-making.