Introduction: Diagnostic diversity has been in the focus of several studies of health services research. As the fraction of people with statutory health insurance changes with age and gender it is assumed that diagnostic diversity may be influenced by these parameters.

Methods: We analyze fractions of patients in Schleswig-Holstein with respect to the chapters of the ICD-10 code in outpatient treatment for quarter 2/2016 with respect to age and gender/sex of the patient. In a first approach we analyzed which diagnose chapters are most relevant in dependence of age and gender. To detect diagnostic diversity, we finally applied Shannon's entropy measure. Due to multimorbidity we used different standardizations.

Results: Shannon entropy strongly increases for women after the age of 15, reaching a limit level at the age of 50 years. Between 15 and 70 years we get higher values for women, after 75 years for men.

Discussion: This article describes a straight forward pragmatic approach to diagnostic diversity using Shannon's Entropy. From a methodological point of view, the use of Shannon's entropy as a measure for diversity should gain more attraction to researchers of health services research.