Dynamical difference in patients encounters involving uncontrolled diabetes: An orbital decomposition analysis

David Katerndahl, Michael L. Parchman

Research output: Contribution to journalArticlepeer-review

14 Scopus citations


Rationale Poor glucose control is common in patients with type 2 diabetes. Little is known about the dynamics within the doctor-patient encounter that might explain this phenomenon. The purpose of this study was to compare dynamics of encounters with and without a hypoglycaemic medication change for patients with poorly controlled diabetes. Methods The doctor-patient encounters of 182 patients with type 2 diabetes from 20 primary care clinics were audio-recorded and transcribed. Encounters were coded using the Davis Observation Codes (DOCs), classifying content into 20 different categories, for example, chatting or history taking, at 15 second intervals. Of the 60 encounters in which the A1C > 8.0, 25 involved a medication change. Fifteen patients were randomly selected from those with a change in medication as well as fifteen patients from those without a change in medication for analysis using orbital decomposition. 'Orbital decomposition' is an analytic technique based on symbolic dynamics in which categorical time series data, such as a string of DOCs, are used to identify amount of complexity present and recurrent patterns of strings. Results Encounters with a change were longer (mean 20 versus 15.5 minutes) and included more time planning treatment (29% versus 23%). Encounters with and without a change displayed similar degrees of non-linearity, but change encounters were slightly more non-linear (DLyapunov = 1.94 versus 1.75). Encounters with a change had more structure to them: they had many more DOC strings (60 versus 33 strings occurring at least three times), and those DOC strings more often linked treatment planning to history taking, chatting, health education, physical examination and compliance assessment. Encounters without a change linked treatment planning to history taking, compliance assessment and nutrition counselling but had no strings with chatting or evaluation and feedback. Conclusion In conclusion, the doctor's decision to change medication may be made before the encounter, thus the different strings of DOC codes observed. Chatting and evaluation and feedback may be strategies to increase trust before recommending a medication change.

Original languageEnglish (US)
Pages (from-to)211-219
Number of pages9
JournalJournal of evaluation in clinical practice
Issue number1
StatePublished - Feb 1 2010


  • Communication
  • Diabetes
  • Nonlinear dynamics
  • Physician-patient relations

ASJC Scopus subject areas

  • Health Policy
  • Public Health, Environmental and Occupational Health


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