Abstract
BACKGROUND: Preventive care - asking, advising or referring patients for help with smoking, nutrition, alcohol, physical activity, and weight (SNAP-W) - is not consistently provided in routine outpatient care due to barriers such as time, other priorities, and forgetfulness. Digital health interventions (DHIs) integrated into routine care offer a promising solution and are acceptable to clinicians and patients. A systematic review is needed to synthesise existing evidence on the effectiveness of DHIs that engage patients, alongside routine care, to provide preventive care targeting SNAP-W in outpatient settings. METHODS: We will include randomised and non-randomised studies that compare a DHI supporting the provision of preventive care for SNAP-W health behaviours with usual care. The DHI must integrate with routine clinician-provided care. Participants will be adult patients/clients of any outpatient healthcare service. The primary outcomes will be provision/receipt of preventive care elements addressing the SNAP-W health behaviours. Secondary outcomes will include SNAP-W behaviour change outcomes. Eligible studies will be identified via MEDLINE, EMBASE, PsycINFO, Scopus, and CINAHL. Two reviewers will independently conduct study selection, data extraction, and risk of bias assessment, with a third resolving disagreements. Risk of bias will be assessed using Cochrane RoB-2 for randomised and ROBINS-I for non-randomised trials. If feasible, a meta-analysis will be conducted to estimate the pooled effect of DHIs by health behaviour. Exploratory sub-group (e.g., type of clinical setting, preventive care element) analyses will be conducted to determine possible causes of statistical heterogeneity. If a meta-analysis is not feasible, results will be summarised using direction of effect per the Synthesis Without Meta-analysis guidelines. DISCUSSION: This review will identify whether DHIs that engage patients as part of outpatient health care are effective at improving delivery of SNAP-W preventive care for adults attending these services. These findings will be of interest to service providers, policy makers and implementation researchers seeking to improve health outcomes through routine preventive care provision. SYSTEMATIC REVIEW REGISTRATION: PROSPERO CRD420251067831.