BackgroundMedical apps are widely available, increasingly used by patients and clinicians, and are being actively promoted for use in routine care. However, there is little systematic evidence exploring possible risks associated with apps intended for patient use. Because self-medication errors are a recognized source of avoidable harm, apps that affect medication use, such as dose calculators, deserve particular scrutiny. We explored the accuracy and clinical suitability of apps for calculating medication doses, focusing on insulin calculators for patients with diabetes as a representative use for a prevalent long-term condition.MethodsWe performed a systematic assessment of all English-language rapid/short-acting insulin dose calculators available for iOS and Android.ResultsSearches identified 46 calculators that performed simple mathematical operations using planned carbohydrate intake and measured blood glucose. While 59% (n = 27/46) of apps included a clinical disclaimer, only 30% (n = 14/46) documented the calculation formula. 91% (n = 42/46) lacked numeric input validation, 59% (n = 27/46) allowed calculation when one or more values were missing, 48% (n = 22/46) used ambiguous terminology, 9% (n = 4/46) did not use adequate numeric precision and 4% (n = 2/46) did not store parameters faithfully. 67% (n = 31/46) of apps carried a risk of inappropriate output dose recommendation that either violated basic clinical assumptions (48%, n = 22/46) or did not match a stated formula (14%, n = 3/21) or correctly update in response to changing user inputs (37%, n = 17/46). Only one app, for iOS, was issue-free according to our criteria. No significant differences were observed in issue prevalence by payment model or platform.ConclusionsThe majority of insulin dose calculator apps provide no protection against, and may actively contribute to, incorrect or inappropriate dose recommendations that put current users at risk of both catastrophic overdose and more subtle harms resulting from suboptimal glucose control. Healthcare professionals should exercise substantial caution in recommending unregulated dose calculators to patients and address app safety as part of self-management education. The prevalence of errors attributable to incorrect interpretation of medical principles underlines the importance of clinical input during app design. Systemic issues affecting the safety and suitability of higher-risk apps may require coordinated surveillance and action at national and international levels involving regulators, health agencies and app stores.Electronic supplementary materialThe online version of this article (doi:10.1186/s12916-015-0314-7) contains supplementary material, which is available to authorized users.

Purpose: The North West London Integrated Care Pilot (NWL ICP), which commenced in late 2011, included as one aim improved contol of diabetes in high risk patients. ICP patients were discussed at a multidisciplinary group meeting and received a detailed care plan. Objectives: We compared HbA1c (117,028 test results), cholesterol and systolic blood pressure levels in 10,111 ICP patients with diabetes and a comparator group of 2,720 patients in ICP practices with diabetes but without Care Plans, and using primary care data measured trends in over time, after controlling for a wide range of patient and clinical factors. The period analysed extended from 1/4/2004 until 30/4/2013. Results: Patients in the ICP group had more HbA1c tests compared to non-ICP patients. While the recent ICP group HbA1c results were slightly better than the non-ICP group, their HbA1c was slightly lower than the non-ICP group initially. ICP patients were exposed to the ICP, on average, for 5.9 months. In the combined statistical analysis, ethnicity, deprivation, test year and Type 2 diabetes were risk factors for a higher HbA1c. We also found that HbA1c decreased significantly in ICP patients, by 1.13 mmol/mol per year of exposure, in the multivariable combined group analysis with adjustment for other confounders. In the analysis of the non-ICP group alone, "theoretical" duration in the ICP was also significantly associated with a fall in HbA1c. There is, therefore, some evidence of either contamination in non-ICP patients, or the effects of some other unmeasured confounder on HbA1c levels. Cholesterol increased significantly, by 0.04 mmol/l and systolic blood pressure by 0.3 mmHg per year of ICP exposure. Conclusions: after controlling for most other important confounders, there was evidence of a significant fall in HbA1c values in ICP practices, but not in other measures of diabetes control.