I was always technically inclined, and majored in physics in college, then did graduate work in Cybernetic Systems. Cybernetics has come to mean computer and internet related technology, but when it was first used in the 1940s it referred to communication and engineering control systems. It was in that graduate school program that I learned of adaptive control and model-based control, as opposed to traditional feedback control.
Late Onset Diagnosis
I was well established in my engineering career in 1984 when, at age 39, I came down with Type 1 Diabetes (T1D). This seemed unusual for me because in general I rarely got sick. I thought a strong immune system was a good thing to have, but there are a few places where this is not so good, and one is with autoimmune diseases like diabetes. I had been infected by something that confused my immune system and caused it to attack my own pancreas, destroying the islet cells that produce insulin. My ‘Honeymoon period’ took about a month for the destruction to complete, but at the end I had T1D.
Research was how I Coped with my T1D
My way of coping with this, after being placed on an Rx of NPH insulin at first, was to try to understand glucose management from a technical standpoint as a cybernetic control system. With this new interest in T1D, I began researching it, reading scientific papers in medical journals, and I joined the American Diabetes Association as a professional member, attending their Scientific Sessions (convention) every June.
Technology Began to Help
Until the mid-1970s there had not been many advances in diabetes treatment since longer-acting insulin (NPH) had been created in 1946 when T1D management was limited to animal-based Regular and NPH insulin, and urine glucose was the only measurement tool. As a practical matter, this required consistent food intake (the same sort of thing, eaten at the same time) with minimal simple sugars to be effective. In the late 1970s, insulin preparations became purified and hemoglobin A1c assays (HbA1c) provided an indication of overall control. Even more importantly, self-monitoring of blood glucose (SMBG) became available using a cumbersome blood glucose test (Chemstrips) that was much better than urine testing. This allowed the basal-bolus approach previously used for continuous subcutaneous insulin infusion (CSII) pump therapy to be adapted for use in multiple daily injection (MDI) regimens as a replacement for the NPH and Regular insulin Split-Mixed regimen.
Therapy Evolved with Better BG Measurement
While this progress was generally viewed as an attempt to minimize blood glucose, it was unclear high BG per se was the cause of diabetes complications, but with these advances making intensive treatment of T1D possible, it set the stage for the Diabetes Control and Complications Trial (DCCT), which was launched in 1983 to answer that question. In 1993 the results were so clear the trial was terminated early and CSII use was greatly expanded, despite its cost. Insulin doses were typically still prescribed, but those doing the prescribing didn’t have much to go on when it came to optimizing the dose quantities.
Treatment was too Simplistic
In my efforts to learn more about T1D, I was disappointed to discover that most diabetes treatment regimens were based on a simplistic feedback-control understanding used to adapt to the necessarily consistent diet. With my expertise in adaptive control systems and model-based control, I knew there were better means to manage my blood glucose, yielding more flexibility at least, if not better control. So I began writing papers in an attempt to educate healthcare professionals about the engineering control that isn’t taught in medical school.
First Scientific Papers
There was a reluctance to use mathematical models in physiology at the time, and there was a controversy over how to measure insulin sensitivity, which was (and remains) an issue with Type 2 patients. My first scientific paper addressed this issue, “The use of models in the self-management of insulin dependent diabetes mellitus”, Computer Methods and Programs in Biomedicine (July/August 1990). This was not a clinical journal, but it got me involved in understanding how to best achieve glucose control, and of course, there was a fair amount of progress in glucose related technology to learn about.
Later in the 1990s, I wrote two papers covering the body as a system. One covering the food input, “Minimal model of food absorption in the gut”, Medical Informatics (January-March 1997) and one for insulin therapy as a control input, “Controlling blood glucose: insights from an engineering control systems perspective”, Medical Informatics (January-March 1997). When I was writing these papers in the mid-1990s, new, rapid-acting insulins were developed. The first was called Lispro (Admelog®, Humalog®, Humalog® Mix50/50, Humalog® Mix75/25), followed by Aspart (Fiasp®, NovoLog®, NovoLog® Mix 70/30). There had been slower insulins, from NPH to Lente and Utralente, but these were the first insulins to be faster acting than Regular insulin, especially the new human Regular insulin developed using recombinant DNA technology.
About five years after writing those papers, continuous glucose monitors became available and expanded control possibilities even further. In 2003, extra long-acting insulins Detemir and Glargine became available for T2D, but it didn’t take long for them to be inappropriately used as T1D basal insulins as well, perhaps because my Controlling Blood Glucose article was not widely read (it was not published in a clinical journal, either), and the role of basal insulin in the basal-bolus regimen was not well understood.
My Opinions and Experience
My education as a control systems engineer, and the perspectives gained from learning about diabetes control personally and writing my journal papers form a large part of this series.
- B.S. in Physics (1968), Harvey Mudd College, Claremont, California.
- Graduate work in Cybernetics (1972-1973), San José State University.
- Courses in Communications, Digital Signal Processing, Filtering, and Adaptive Modeling in the Dept of Electrical Engineering (1982-1983), Stanford University.
- Object-Oriented Programming extension course (1988), UC Santa Cruz.
- Epidemiology extension course [TV Audit] (2003), University of Washington.
- “Capacitance-based dose measurements in syringes”, US Patent 6,110,148 issued August 29, 2000.
- “Diabetes Management System and Method for Controlling Blood Glucose” US Patent 5,822,715 issued November 17, 1998.
- “Controlling blood glucose: insights from an engineering control systems perspective,” Medical Informatics (January-March 1997).
- “Minimal model of food absorption in the gut,” Medical Informatics (January-March 1997)
- “The use of models in the self-management of insulin dependent diabetes mellitus” Computer Methods and Programs in Biomedicine, (July/August 1990)
- “Use of Physiologic Models as an Aid to Patient Decision Making in the Self Management of IDDM,” International Federation of Automatic Control, Workshop on decision support for Patient Management: Measurement, Modeling, and Control, City University, London, (1989).
- “CCWS: A Computer-Based, Multimedia Information System,” IEEE COMPUTER magazine (October 1985)
- “ADEPT: Adaptive Electromagnetic Predictive Technique,” SRI International (1981)
- “Assessment of Agreement among Several Raters Formulating Multiple Diagnoses,” Journal of Psychiatric Research, (January 1981)
- “A Comparison of Graphical Representations of Multidimensional Psychiatric Diagnostic Data,” Wang, P. (ed.), Graphical Representations of Multivariate Data (Academic Press, 1978)
Peer Reviewer for
- Journal of Diabetes Science and Technology
- Annals of Biomedical Engineering
Content of Series
There are six articles in the series plus a dedicated section on Acronyms and References.
- My T1D Journey as a Systems Engineer
- Physiology of Managing T1D
- Food Effect on Glucose
- Basal Insulin Management in T1D
- Bolus Insulin Management in T1D
- Using CGMs, Insulin Pens, and Pumps
- Acronyms and References
See description of full article series here.