Systematic review of the development, implementation and availability of smart‐phone applications for assessing Type 2 diabetes risk

Randomized controlled trials have shown that progression from impaired glucose regulation to Type 2 diabetes mellitus can be prevented through lifestyle modification or pharmacological intervention [1]. Identifying those at high risk of developing Type 2 diabetes is a priority in order for preventative interventions to be initiated. Risk scores are one way of identifying this group [2]. Questionnaire-based scores, such as FINDRISC [3], allow people to assess their own risk and inform them about seeking further testing if needed. Such risk scores are available for completion online; for example, the Leicester Self-Assessment Score is hosted on the Diabetes UK website [4]. More recently, smart-phone applications (apps) are also being released, which allow people to assess their own risk and, in some cases, learn about how they can reduce their risk. Unlike traditional mobile phones, smart-phones allow users to install, configure and run specialized apps of their choosing. It is estimated thatworldwide 700million people are smart-phones users, increasing to three billion by 2017 [5]. Smart-phone technology could be a means of accessing people who do not routinely attend for screening or who are not registered with a general practice. From a search carried out on 19 June 2012, we identified 11 apps for assessing the risk of Type 2 diabetes; seven of these are freely available (see Table 1) and four require payment for download [range £0.61 (€0.76) up to £0.69 (€0.86)]. Of the apps that are freely available, two specifically stated that they used the validated FINDRISC, two others also used the FINDRISC, but this was not explicitly stated. Three of the apps did not state whether the score used was validated. Of the four scores using the FINDRISC, three displayed the level of risk in line with the original validated FINDRISC. The TonicMinds app had used FINDRISC, but displayed the level of risk as the percentage chance of developing Type 2 diabetes over the next 10 years rather than the validated risk groupings. The Lloyds pharmacy app gives the level of risk for developing Type 2 diabetes, but no time frame, and the A.Iranhoten app displays the risk of either already having Type 2 diabetes or developing it over the next 5 years. The style and level of lifestyle advice given by each of the apps also varied, ranging from no advice to a facility for the user to change their risk factors and reassess what impact this would have on their score. Of the four apps that are not freely available, only one explicitly stated that it was based on a validated risk score (QDScore). Additionally, we carried out a literature review and found no studies describing the development, validation and implementation of these apps. This lack of robust evidence regarding the use of apps for self-assessment of diabetes risk is a cause for concern. If apps are using unvalidated scores, these could cause a number of potential problems. False negatives could result in people being falsely reassured, while a large number of false positives could overwhelm services. Furthermore, receiving a high score may also increase levels of anxiety [6]. None of the apps specifically described the population for which the score was validated. It is well reported that risk scores work well in the population they were developed for and may not work equally well in other populations [7]. All risk scores are developed using a cohort of a specific age range; care should therefore be taken when extrapolating beyond this age group. Additionally, the FINDRISC was designed as a paper-based tool and therefore had to be relatively simple in its scoring system. Utilising app technology means that users do not need to calculate and interpret their own score, so a more sophisticated model could be applied. Age, for example, could be included as a continuous variable to increase power; interactions between variables and non-linear terms could also be considered. Using a more sophisticated score may increase the levels of discrimination, but more research would be required to validate modifications to existing risk scores. Following this review, we would like to make the following recommendations for future developments in this area. The risk score used must have been externally validated and details of the specific score used must be given within the app documentation, along with information about the populations included in the validation process. Once a score is established, the development of the app should include professionals with expertise in relevant technology, experts in diabetes prevention and potential users. This process should inform the way in which the level of risk is communicated and lifestyle advice that is provided. There is substantial evidence regarding risk communication and how the level of risk is best understood. It has been shown that risk communication solely based on words can be ineffective, such as informing someone that they are at low risk; these qualitative terms should therefore be given alongside numerical data. Absolute risk should be displayed rather than relative risk [8]. Finally, all apps should go through user testing before they are released. As suggested by Noble et al. [9], risk scores are complex interventions and therefore they should be evaluated for efficacy and any possible adverse outcomes in the same way as any other prevention intervention. In conclusion, the evidence base for the existing apps for assessing Type 2 diabetes risk is lacking. Smart-phone apps may increase the uptake to screening and may motivate behaviour change if they are developed and implemented using robust research and evaluation methodology.