A recent study published in the BMC Medicine medical journal concluded that smartphone apps that offer an insulin dose calculator may actively contribute to incorrect dose recommendations, according to the systematic assessment of 46 insulin dose calculator apps available on iOS and Android in the UK App Store. Apps data was collected in August 2013.

Researchers explained in the abstract that inaccurate dose recommendations put "current users at risk of both catastrophic overdose and more subtle harms resulting from suboptimal glucose control".

The assessment found that 59 percent of the apps offered a clinical disclaimer that suggested the patient discuss their condition with a healthcare professional before using the calculator and use personal judgement when interpreting the results. But, 91 percent of the apps had no numeric validation, meaning impossibly high or low values would be accepted if a user entered them -- even negative values were accepted.

Some 59 percent of apps calculated a dosage even if one or more values had not been entered; 48 percent of apps used ambiguous terminology that could have been misinterpreted by the user; and 9 percent of apps "did not use adequate numeric precision", for example, some apps offered a data field for measurements in mmol/L that accepted only whole integers.

Researchers also found that 67 percent of apps showed a risk of generating inappropriate dose recommendations. Some 48 percent of this group of apps violated basic clinical assumptions, 37 percent did not correctly update in response to changing user inputs, and 14 percent did not match a stated formula.

"Healthcare professionals should exercise substantial caution in recommending unregulated dose calculators to patients and address app safety as part of self-management education," researchers wrote in the abstract. "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."