A systematic review of Theory of planned Behaviour interventions for chronic diseases in low health-literacy settings

Background: The Theory of planned Behaviour (TPB) has been effectively used for designing and evaluating behavioural interventions for improving health outcomes in affluent populations of the global north. However, there is a need to establish whether such interventions can be used successfully with change in settings – with poor socio-economic and low health literacy levels, prevalent mostly in LMICs, which carry most of the burden of chronic diseases globally. Aim: This systematic review (SR) collated evidence of TPB based interventions in low health literacy settings for its effectiveness and feasibility. Methods: This SR followed methods of data analysis and reporting as per PRISMA 2020 guidelines. Interventional studies using at least two constructs of TPB and conducted in LMICs were selected, PICO tool was used, and risk of bias was evaluated using RoB 2 and ROBBINS-I tool. Results: A total of 4281 titles/abstracts were reviewed, 11 met the criteria for full-text screening and four were finally selected for narrative synthesis. Feasibility and fidelity of all studies were established – through recruitment rates (>80%), integrity of intervention delivery, completion rates (>80%) and timely completion. All were effective in changing health behaviour and TPB constructs, and in achieving their objectives. Three studies had some concerns/moderate risk of bias and one had high risk of bias. Conclusion: All studies demonstrated effectiveness of TPB interventions as well as their feasibility and fidelity in LMIC settings, although quality of most studies were moderate. More studies are required to gather definitive evidence of feasibility and effectiveness in LMICs.