Study designs of evaluations included in the review
Randomised controlled trials (RCTs), non-randomised controlled studies and uncontrolled studies were eligible for inclusion.
Specific interventions included in the review
Studies reporting the use of MI to promote behaviour change were eligible for inclusion. Where reported, the MI sessions varied between the included studies; with interventions ranging from single to multiple sessions. In some studies it was unclear whether a brief or full therapy session had been delivered. Usual care was the most common comparator.
Participants included in the review
Studies of participants suffering from, or at risk of developing, common physical illnesses were eligible for inclusion. Studies of patients with the human immunodeficiency virus were excluded. The participants in the included studies had diabetes, asthma, hyperlipidaemia or hypertension, were undergoing cardiac rehabilitation, or were awaiting coronary artery bypass surgery. Where reported, the mean age ranged from 16 to 62 years.
Outcomes assessed in the review
All outcomes were of interest. The outcomes reported in the included studies varied considerably between studies and encompassed cognitive (e.g. self-efficacy and knowledge), emotional (e.g. quality of life, anxiety and depression), lifestyle change (e.g. exercise and alcohol intake) and physiological (e.g. weight and cholesterol) variables. The length of follow-up in the included studies ranged from 2 weeks to 15 months.
How were decisions on the relevance of primary studies made?
One reviewer screened abstracts and two reviewers screened full papers. Any discrepancies were discussed and resolved.