Myocardial infarction in the practices of a group of private physicians—A comparison of patients with and without diabetes—II: The first two years, and a discussion of methodology

1. 1. A 2-year follow-up of patients having acute myocardial infarction is presented. It is based upon all myocardial infarctions which occurred in the private practices of a group of internists. Diagnosis was made according to a predetermined set of detailed criteria. The status at the end of 2 years was known for all patients. 2. 2. The overall fatality rate was 37 per cent. 3. 3. The fatality rate was lower following a first infarction than following other than a first infarction. 4. 4. Certain complications occurring during the first 30 days following infarction were not associated with an increased 30-day to 2-year fatality if the infarction was the patient's first. If the patient had had a previous infarction, the occurrence of these complications was associated with a higher fatality of borderline significance. 5. 5. The development of any one, or more than one, of certain complications during the first 30 days following the infarction was associated with a greater 2-year fatality in those with diabetes than in those without diabetes. 6. 6. Among patients with diabetes mellitus: (a) The 30-day to 2-year fatality was significantly higher than among those without it. This was true both for those having a first infarction and those having other than a first infarction. (b) There was no apparent relationship between the 30-day to 2-year fatality and the insulin dose, the degree of control or the duration of the diabetes preceding the index infarction. 7. 7. Some of the issues which must be considered in the design and analysis of a prospective prognostic study are discussed.