Table.

Defining a complex intervention at three levels for health services research: case of secondary prevention of ischaemic heart disease

	Levels for defining intervention
Key issue	Level 1: Theory and evidence	Level 2: Essential tasks and processes*	Level 3: People and context
Target population	Focus on high risk patients2 3	Identification of high risk patients Recruitment of patients to intervention	Patients seen in secondary care with newly diagnosed angina or myocardial infarction
Service provision	Gaps in provision of secondary preventive care for patients with established ischaemic heart disease, in both primary and secondary care, in particular:
	Lack of primary-secondary care liaison	Effective linking of patient care from hospital through general practice	Two existing local cardiac rehabilitation sisters Three new cardiac liaison nurses working between two hospitals in Southampton 67 general practices
	Lack of appropriate prescribing	Delivery of appropriate prescribing for patients	General practitioner guidelines, monitoring by practice nurses
	Lack of cardiac rehabilitation4 6	Delivery of cardiac rehabilitation for patients	Limited local provision of cardiac rehabilitation services, supplemented by cardiac liaison nurses
Changing behaviour	Effective ways of enabling behaviour change:
	Guideline development19	Provision of prescribing guidelines for general practitioners and nurses, sent with patient	Local expert group to formulate, general practitioners to implement supported by practice nurses
	Behavioural techniques, e.g. patient prompts	Patient held booklet providing self monitoring and prompts to care	Practice nurses to implement supported by cardiac liaison nurses and general practitioners
	Theoretical models (applicable to patients and practitioners):
	Self efficacy20	Provision of individualised self management plans
	Stages of change21 Motivational interviewing22	Seminars for nurses Support groups for nurses	Practice nurses trained by local health promotion services, using the existing Helping People Change training package (often in their own time)

^*What needed doing—generalisable. 

^†Who was involved, and where—specific to local setting.