An in-silico proof-of-concept investigation of a combined glucose-insulin bolus quick dynamic insulin sensitivity test

BackgroundThe 30-min quick dynamic insulin sensitivity test (DISTq30) uses two blood-glucose measurements from a dynamic insulin sensitivity test protocol to provide low-cost, real-time insulin sensitivity (SI) measurements. However, the DISTq30 clinical protocol contains a potentially redundant 10-min period between glucose and insulin boluses that occur at t = 0 and t = 10 min.MethodsA proposed protocol (DISTq20) reduces the DISTq30 test duration to 20 min and administers a combined 10 g glucose and 1 U insulin bolus at t = 0. The proposed protocol was evaluated against the clinically validated DISTq30 in a Monte Carlo analysis. 313 clinical responses to the dynamic insulin sensitivity and secretion tests (DISST) from three different studies were used to provide realistic parameter value sets. These values were used to create realistic in-silico responses to DISTq20 and DISTq30 protocols. Each simulated response was ‘sampled’ at the appropriate times and SI was identified 200 times in a Monte Carlo analysis with added random assay error for each protocol and parameter set. In a second analysis, the DISTq20 response was simulated with 0–50% inhibition of the first phase insulin response to assess robustness to this potential effect.ResultsSimulated noise had a very similar effect on DISTq30 and DISTq20 SI values (R = 0.99). DISTq20 overestimated DISTq30 SI by a median 1.7% (IQR −4.3% to 7.3%). The second analysis showed that DISTq20 results were robust to variance in first phase insulin secretion (R = 0.97). DISTq20 and DISTq30 both had a median CV of 7.9%.ConclusionsInconsequential differences between SI values found by the DISTq30 and the DISTq20 in-silico indicate that the DISTq20 may produce similar clinical results to the DISTq30. Further analysis showed that the identification method was robust to the assumption of zero insulin suppression.

► DISTq30 is a clinically validated, low-cost, high-resolution insulin sensitivity test.
► This investigation proposes a lower intensity test (DISTq20).
► In-silico methods were used to assess the efficacy of DISTq20 against DISTq30.
► DISTq20 outcomes were very similar to DISTq30 (R = 0.96–0.99).
► This outcome implies that the lower cost DISTq20 test is feasible.