title: Smartphone apps for calculating insulin dose: a systematic assessment.
abstract: BACKGROUND
  Medical 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.
  
  
  METHODS
  We performed a systematic assessment of all English-language rapid/short-acting insulin dose calculators available for iOS and Android.
  
  
  RESULTS
  Searches 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.
  
  
  CONCLUSIONS
  The 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.
authors.affiliation: Global eHealth Unit, Imperial College London, Reynolds Building, St Dunstans Road, London, W6 8RP, UK. c.huckvale@imperial.ac.uk.
authors.forename: Kit
authors.initials: K
authors.lastname: Huckvale
authors.affiliation: Global eHealth Unit, Imperial College London, Reynolds Building, St Dunstans Road, London, W6 8RP, UK. samanta.adomaviciute@gmail.com.
authors.forename: Samanta
authors.initials: S
authors.lastname: Adomaviciute
authors.affiliation: CRG, École polytechnique, Palaiseau, France. jose-tomas.prieto@polytechnique.edu.
authors.forename: José Tomás
authors.initials: JT
authors.lastname: Prieto
authors.affiliation: Department of Endocrinology, Tan Tock Seng Hospital, Singapore, Singapore. melvin.leow@sics.a-star.edu.org.|Office of Clinical Sciences, Duke-NUS Graduate Medical School, Singapore, Singapore. melvin.leow@sics.a-star.edu.org.|Singapore Institute for Clinical Studies, A*STAR, Singapore, Singapore. melvin.leow@sics.a-star.edu.org.
authors.forename: Melvin Khee-Shing
authors.initials: MK
authors.lastname: Leow
authors.affiliation: Global eHealth Unit, Imperial College London, Reynolds Building, St Dunstans Road, London, W6 8RP, UK. josip.car@imperial.ac.uk.|Health Services and Outcomes Research Programme, LKC Medicine, Imperial College - Nanyang Technological University, Singapore, Singapore. josip.car@imperial.ac.uk.
authors.forename: Josip
authors.initials: J
authors.lastname: Car
mesh_terms: D001786:Blood Glucose / Q000032:analysis*; D040421:Cell Phone; D003920:Diabetes Mellitus / Q000097:blood / Q000188:drug therapy*; D006801:Humans; D061385:Insulins / Q000008:administration & dosage*; D063731:Mobile Applications; D012648:Self Care / Q000379:methods*
chemical_list: D001786:Blood Glucose; D061385:Insulins