Assessments of treatment adherence are ignored in clinical trials, but could help to increase uptake of evidence-based therapies, the researchers believe.
Dr Florian Vogt and colleagues from King's College London asked 13 GPs their views on the effectiveness of eight medical interventions.
The treatments asked about were nicotine replacement therapy, diclofenac and statins, weight loss surgery, cognitive behavioural therapy for depression, diet and exercise to prevent type-2 diabetes, statins to prevent heart disease and group therapy for smoking cessation.
The researchers found that GPs judged the effectiveness of interventions by considering the impact of therapies and the extent to which a treatment involves patient effort.
Dr Vogt pointed out that patient effort is ignored in clinical trials, where evaluations are only based on recruited patients. 'Many patients are excluded and many may decline to take part for a number of reasons,' they said.
'The randomisation underlying trials loses an important aspect of patient behaviour, and effectiveness is reported on average; yet there is considerable variability between patients' outcomes depending on desire and ability to adhere,' he added.
The researchers suggest that future research should examine patient adherence to treatment, so that uptake of evidence-based treatments can be improved.
'Deciding whether the patient is able and motivated to attend and adhere is an important as-pect of translating trial evidence into practice,' they said.
- Implementation Science Online 2010