The Open Medical Informatics Journal

2009, 3 : 65-76
Published online 2009 December 2. DOI: 10.2174/1874431100903010065
Publisher ID: TOMINFOJ-3-65

RESEARCH ARTICLE
 DISTq: An Iterative Analysis of Glucose Data for Low-Cost, Real-Time and Accurate Estimation of Insulin Sensitivity

Paul D. Docherty1 , J. Geoffrey Chase, *,1 , Thomas Lotz1 , Hann Hann1 , Geoffrey M. Shaw2 , Juliet E. Berkeley2 , J.I. Mann3 and Kirsten McAuley3
1 Department of Mechanical Engineering, University of Canterbury, New Zealand
2 Department of Medicine, Christchurch School of Medicine, University of Otago, Christchurch, New Zealand
3 Edgar National Centre for Diabetes Research, University of Otago, Dunedin, New Zealand

* Address correspondence to this author at the Department of Mechanical Engineering, University of Canterbury, New Zealand; E-mail: geoff.chase@canterbury.ac.nz

ABSTRACT

Insulin sensitivity (SI) estimation has numerous uses in medical and clinical situations. However, highresolution tests that are useful for clinical diagnosis and monitoring are often too intensive, long and costly for regular use. Simpler tests that mitigate these issues are not accurate enough for many clinical diagnostic or monitoring scenarios. The gap between these tests presents an opportunity for new approaches.

The quick dynamic insulin sensitivity test (DISTq) utilises the model-based DIST test protocol and a series of population estimates to eliminate the need for insulin or C-peptide assays to enable a high resolution, low-intensity, real-time evaluation of SI. The method predicts patient specific insulin responses to the DIST test protocol with enough accuracy to yield a useful clinical insulin sensitivity metric for monitoring of diabetes therapy.

The DISTq method replicated the findings of the fully sampled DIST test without the use of insulin or C-peptide assays. Correlations of the resulting SI values was R=0.91. The method was also compared to the euglycaemic hyperinsulinaemic clamp (EIC) in an in-silico Monte-Carlo analysis and showed a good ability to re-evaluate SIEIC (R=0.89), compared to the fully sampled DIST (R=0.98)

Population-derived parameter estimates using a-posteriori population-based functions derived from DIST test data enables the simulation of insulin profiles that are sufficiently accurate to estimate SI to a relatively high precision. Thus, costly insulin and C-peptide assays are not necessary to obtain an accurate, but inexpensive, real-time estimate of insulin sensitivity. This estimate has enough resolution for SI prediction and monitoring of response to therapy. In borderline cases, re-evaluation of stored (frozen) blood samples for insulin and C-peptide would enable greater accuracy where necessary, enabling a hierarchy of tests in an economical fashion.