Implementation strategies to increase smoking cessation treatment provision in primary care: a systematic review of observational studies.

Background: Internationally, there is an 'evidence-practice gap' in the rate healthcare professionals assess tobacco use and offer cessation support in clinical practice, including primary care. Evidence is needed for implementation strategies enacted in the 'real-world'.

Aim: To identify implementation strategies aiming to increase smoking cessation treatment provision in primary care, their effectiveness, cost-effectiveness and any perceived facilitators and barriers for effectiveness.

Methods: 'Embase', 'Medline', 'PsycINFO', 'CINAHL', 'Global Health', 'Social Policy & Practice', 'ASSIA Applied Social Sciences Index and Abstracts' databases, and grey literature sources were searched from inception to April 2021. Studies were included if they evaluated an implementation strategy implemented on a nation-/state-wide scale, targeting any type of healthcare professional within the primary care setting, aiming to increase smoking cessation treatment provision.

Primary Outcome Measures: implementation strategy identification, and effectiveness (practitioner-/patient-level).

Secondary Outcome Measures: perceived facilitators and barriers to effectiveness, and cost-effectiveness. Studies were assessed using the Risk Of Bias In Non-randomized Studies of Interventions (ROBINS-I) tool. A narrative synthesis was conducted using the Expert Recommendations for Implementing Change (ERIC) compilation and the Consolidated Framework for Implementation Research (CFIR).

Results: Of 49 included papers, half were of moderate/low risk of bias. The implementation strategy domains identified involved utilizing financial strategies, changing infrastructure, training and educating stakeholders, and engaging consumers. The first three increased practitioner-level smoking status recording and cessation advice provision. Interventions in the utilizing financial strategies domain also appeared to increase smoking cessation (patient-level). Key facilitator: external policies/incentives (tobacco control measures and funding for public health and cessation clinics). Key barriers: time and financial constraints, lack of free cessation medications and follow-up, deprioritisation and unclear targets in primary care, lack of knowledge of healthcare professionals, and unclear messaging to patients about available cessation support options. No studies assessed cost-effectiveness.

Conclusions: Some implementation strategy categories increased the rate of smoking status recording and cessation advice provision in primary care. We found some evidence for interventions utilizing financial strategies having a beneficial impact on cessation. Identified barriers to effectiveness should be reduced. More pragmatic approaches are recommended, such as hybrid effectiveness-implementation designs and utilising Multiphase Optimization Strategy methodology.

Protocol Registration: PROSPERO:CRD42021246683.