Predicting intentions and behaviours in populations with or at-risk of diabetes: A systematic review

• Intention was the most predictive construct for diabetes self-care behaviours (18% – 76% of explained variance).
• Studies included cross-sectional (n = 7); prospective (n = 5) and randomised control trials (n = 4).
• Explained variance for intentions were similar across the study designs and RCTs provided slightly stronger evidence for predicting diabetes-related behaviour.
• The predictive utility of the TPB is behaviour specific and depends largely on the target population.

PurposeTo systematically review the Theory of Planned Behaviour studies predicting self-care intentions and behaviours in populations with and at-risk of diabetes.MethodsA systematic review using six electronic databases was conducted in 2013. A standardised protocol was used for appraisal. Studies eligibility included a measure of behaviour for healthy eating, physical activity, glucose monitoring, medication use (ii) the TPB variables (iii) the TPB tested in populations with diabetes or at-risk.ResultsSixteen studies were appraised for testing the utility of the TPB. Studies included cross-sectional (n = 7); prospective (n = 5) and randomised control trials (n = 4). Intention (18%–76%) was the most predictive construct for all behaviours. Explained variance for intentions was similar across cross-sectional (28–76%); prospective (28–73%); and RCT studies (18–63%). RCTs (18–43%) provided slightly stronger evidence for predicting behaviour.ConclusionsFew studies tested predictability of the TPB in populations with or at-risk of diabetes. This review highlighted differences in the predictive utility of the TPB suggesting that the model is behaviour and population specific. Findings on key determinants of specific behaviours contribute to a better understanding of mechanisms of behaviour change and are useful in designing targeted behavioural interventions for different diabetes populations.