Table 1 Inclusion criteria and specifications

Population

Any

Any population who received or were targeted by a healthcare or health promotion intervention

Implementation strategy^a

• Single implementation strategy: involving one action or process

• Multicomponent implementation strategy: comprising two or more single strategies

• Examples of commonly used single implementation strategies: mailed outreach, reminders, education and training sessions, etc

• Examples of multicomponent strategies: electronic health record-based patient identification plus individualised mailed outreach, quality improvement programme [23], model of care [24], implementation theory, and frameworks [25]

Comparator

• Usual care

• Active comparator

E.g. no implementation strategy or active implementation components

Outcomes

• An implementation outcome had to be a primary focus of the eligible trial

• Secondary outcomes may include health-related outcomes (including biomarkers of diseases), process outcomes (e.g. the amount of time used in prescription), changes in health behaviour, and quality of life

Eight common implementation outcomes [5]:

Acceptability

Adoption (e.g. uptake of the cancer screening programmes)

Appropriateness (e.g. appropriateness of implementing a weight management programme in low-income countries)

Feasibility

Fidelity (e.g. quality of programme delivery)

Implementation cost

Penetration (e.g. the spread of quality improvement programme)

Sustainability (e.g. the maintenance of a health service in the long term)

A full description of the eight implementation outcomes is provided in Additional file 3

Study designs

Any RCTs

Including parallel RCTs, cluster RCTs, stepped-wedge RCTs, pragmatic RCTs, adaptive design, hybrid effectiveness-implementation design

Healthcare settings

• Primary care

• Inpatient

• Secondary care

• Other

Primary care service includes general and family practice, community care, pharmacy, dental and ophthalmic services

Inpatient care provided in the hospital settings

Secondary care service includes general internal medicine, general paediatrics, obstetrics and gynaecology, outpatient

Other may include multiple settings

Evidence-based interventions^a

The evidence is preferably supported by systematic reviews and meta-analyses or a number of effectiveness RCTs

The evidence is expected to be cited in the trial background (e.g. introduction or method sections)

E.g. evidence-based treatment/medications/services, clinical guidelines, cancer screening programmes, health policy

Type of routine data

Electronic health record/electronic medical record/personal health record

E.g. primary care databases

Administrative datasets

E.g. healthcare claims databases, private insurance databases

Registries

E.g. cancer registry, birth/death registry, HIV registry

Use of routine data

Trial participants identification

E.g. EHR data were used to identify eligible patients over 65 years old with blood pressure > 140/90 mmHg

Outcome ascertainment

E.g. data from the HIV registry were analysed to assess the proportion of patients screened for HIV

Intervention delivery

E.g. reminders (as an implementation strategy) integrated into the electronic health record

Type of trials considered in this review

Implementation trial: the aim was to assess the implementation strategies solely on implementation outcomes, as opposed to hybrid designs

E.g. a trial evaluated the effectiveness of a telephone reminder to increase the uptake of mammography screening [26]

Hybrid type II design: the co-primary aims were to determine the impact of the implementation strategies on implementation outcomes and the effectiveness of the health intervention on health outcomes

E.g. a trial examined the effectiveness of the intervention on diabetes and depression and concurrently tested an implementation strategy to increase the use and fidelity of the intervention [27]

Hybrid type III design: the primary focus was on implementation outcomes, with the secondary focus on the intervention outcomes

E.g. a trial evaluated an implementation strategy bundle, with the primary outcomes on the adoption and sustainability of the evidence-based intervention and secondary outcomes on activities of daily living, pain, depression, falls, emergency department visits, and hospitalisations [28]