Text in English / Interactive health communication between the health-care professional (HCP) and patient relationship for diabetes health-care positively contributes to patient-centred care. Hence individual patient concerns are addressed and catered for in the medical system. The purpose of this study was to analyse in-depth how HCP-patient relationships and HCP-HCP teamwork dynamics positively contribute to effective diabetes patient care and treatment adherence. Different health communication models and theories were reviewed and a conceptual framework was developed from the literature. A qualitative case study approach was used to collect data at Stanger Hospital’s diabetes clinic. Data was collected using three different methods, namely in-depth interviews with HCPs and patients individually, observations conducted at the clinic analysing both the HCPs and patients, and finally, documentation that emerged as a third data collection method where patient files and diabetes educational material were analysed at the clinic. Triangulation by means of the three methods ensured that reliable, valid and credible data was collected in the field. Diabetes health-care and treatment management are affected by the social context/social system which includes family and culture. These social factors are acknowledged as core in the literature. However, a single comprehensive health communication model did not exist solely in this regard. The data indicated that at the Stanger Hospital’s diabetes clinic, patient-centred (individual tailor-made treatment plans) care was only implemented after patients had defaulted treatment for reasons linked to their social circumstances. The findings of the study indicate that teamwork was favoured in the HCP-HCP relationship at the diabetes clinic, and that this made a positive contribution to effective diabetes patient care. HCPs were overburdened at the clinic since patient numbers were high and there were staff shortages. The patients’ empirical data indicated that interactive communication positively contributed to their medical concerns being catered for at the diabetes clinic, but this tended to occur only after non-adherence. Patients required care and support from HCPs in order to learn to accept diabetes and manage their illness. / Sociology / D. Litt. et Phil. (Sociology)