Up to now all published experience with intensified insulin therapy has originated from specialized diabetes centres. However, even in diabetes centres and under research conditions intensification of insulin therapy may substantially increase the risk of severe hypoglycaemia. The aim of the present study was to demonstrate the feasibility of effectively and safely transferring intensified insulin therapy based upon a 5-day in-patient treatment and teaching programme from a University diabetes centre to non-specialized general hospitals. A total of nine general hospitals were recruited; the University diabetes centre served as a reference centre. From each general hospital a nurse and a dietitian were trained as diabetes educators, and a diabetes unit with about 10 beds was organized within each department of internal medicine. A total of 697 consecutively admitted Type 1 (insulin-dependent) diabetic patients (age 26 +/- 7 years, duration of diabetes 8 +/- 7 years) who participated in the programme either in one of the general hospitals (n = 579) or in the reference centre (n = 118) were re-examined after 1, 2 and 3 years. Insulin therapy was intensified to a similar extent in the reference centre and the general hospitals; at the 3-year follow-up about 80% of the patients injected insulin at least three times daily or used continuous subcutaneous insulin infusion (10%), and about 70% reported measuring blood glucose levels more than twice per day. HbA1 levels were lowered (p < 0.0001) to comparable levels, i.e. from 10.6% (reference centre) and 9.9% (general hospital), respectively, at baseline to 9.4% and 9.3%, respectively, at the 3-year follow-up.(ABSTRACT TRUNCATED AT 250 WORDS)