BackgroundThere are thousands of apps promoting dietary improvement, increased physical activity (PA) and weight management. Despite a growing number of reviews in this area, popular apps have not been comprehensively analysed in terms of features related to engagement, functionality, aesthetics, information quality, and content, including the types of change techniques employed.MethodsThe databases containing information about all Health and Fitness apps on GP and iTunes (7,954 and 25,491 apps) were downloaded in April 2015. Database filters were applied to select the most popular apps available in both stores. Two researchers screened the descriptions selecting only weight management apps. Features, app quality and content were independently assessed using the Mobile App Rating Scale (MARS) and previously-defined categories of techniques relevant to behaviour change. Inter-coder reliabilities were calculated, and correlations between features explored.ResultsOf the 23 popular apps included in the review 16 were free (70 %), 15 (65 %) addressed weight control, diet and PA combined; 19 (83 %) allowed behavioural tracking. On 5-point MARS scales, apps were of average quality (Md = 3.2, IQR = 1.4); “functionality” (Md = 4.0, IQR = 1.1) was the highest and “information quality” (Md = 2.0, IQR = 1.1) was the lowest domain. On average, 10 techniques were identified per app (range: 1–17) and of the 34 categories applied, goal setting and self-monitoring techniques were most frequently identified. App quality was positively correlated with number of techniques included (rho = .58, p < .01) and number of “technical” features (rho = .48, p < .05), which was also associated with the number of techniques included (rho = .61, p < .01). Apps that provided tracking used significantly more techniques than those that did not. Apps with automated tracking scored significantly higher in engagement, aesthetics, and overall MARS scores. Those that used change techniques previously associated with effectiveness (i.e., goal setting, self-monitoring and feedback) also had better “information quality”.ConclusionsPopular apps assessed have overall moderate quality and include behavioural tracking features and a range of change techniques associated with behaviour change. These apps may influence behaviour, although more attention to information quality and evidence-based content are warranted to improve their quality.Electronic supplementary materialThe online version of this article (doi:10.1186/s12966-016-0359-9) contains supplementary material, which is available to authorized users.

Disease status scores in AS correlated significantly with anxiety, depression, internality and health status. Interpretation of AS disease scores should take an account of psychological status and the choice of measures used. These findings have important potential applications in AS management and monitoring, including the identification of patients for biological therapies.

Group-based interventions are widely used to promote health-related behaviour change. While processes operating in groups have been extensively described, it remains unclear how behaviour change is generated in group-based health-related behaviour-change interventions. Understanding how such interventions facilitate change is important to guide intervention design and process evaluations. We employed a mixed-methods approach to identify, map and define change processes operating in group-based behaviour-change interventions. We reviewed multidisciplinary literature on group dynamics, taxonomies of change technique categories, and measures of group processes. Using weight-loss groups as an exemplar, we also reviewed qualitative studies of participants' experiences and coded transcripts of 38 group sessions from three weight-loss interventions. Finally, we consulted group participants, facilitators and researchers about our developing synthesis of findings. The resulting 'Mechanisms of Action in Group-based Interventions' (MAGI) framework comprises six overarching categories: (1) group intervention design features, (2) facilitation techniques, (3) group dynamic and development processes, (4) inter-personal change processes, (5) selective intra-personal change processes operating in groups, and (6) contextual influences. The framework provides theoretical explanations of how change occurs in group-based behaviour-change interventions and can be applied to optimise their design and delivery, and to guide evaluation, facilitator training and further research. ARTICLE HISTORY

BackgroundPublished descriptions of group-based behaviour-change interventions (GB-BCIs) often omit design and delivery features specific to the group setting. This impedes the ability to compare behaviour-change interventions, synthesise evidence on their effectiveness and replicate effective interventions. The aim of this study was to develop a checklist of elements that should be described to ensure adequate reporting of GB-BCIs.MethodsA range of characteristics needed to replicate GB-BCIs were extracted from the literature and precisely defined. An abbreviated checklist and a coder manual were developed, pilot tested and refined. The final checklist and coder manual were used to identify the presence or absence of specified reporting elements in 30 published descriptions of GB-BCIs by two independent coders. Reliability of coding was assessed.ResultsThe checklist comprises 26 essential reporting elements, covering intervention design, intervention content, participant characteristics, and facilitator characteristics. Inter-rater reliability for identification of reporting elements was high (95 % agreement, Mean AC1 = 0.89).ConclusionThe checklist is a practical tool that can be used, alongside other reporting guidelines, to ensure comprehensive description and to assess reporting quality of GB-BCIs. It can also be helpful for designing group-based health interventions.Electronic supplementary materialThe online version of this article (doi:10.1186/s12889-015-2300-6) contains supplementary material, which is available to authorized users.