Studies in the epidemiology and preventability of rheumatic fever-I. Demographic factors and the incidence of acute attacks

Incidence rates of hospitalized attacks of acute rheumatic fever in Baltimore were calculated for the 5-yr period 1960-1964. For the age group 5-19 yr, the annual rates were 13.3 per 100,000 for initial attacks, 2.3 for recurrences and 15.6 for all attacks. When a correction was made for the proportion of cases estimated to be treated without hospitalization, the total annual incidence of acute rheumatic fever was approximately 24 per 100,000 population, age 5-19 yr. The non-white to white ratio for incidence rates of hospitalized rheumatic fever was 2.5 for initial attacks and 4 for recurrences. The greatest difference in incidence rates between non-whites and whites is observed in older age groups. The decline of incidence with age observed in whites was not present in non-whites in whom incidence rates remained high in all age groups. Most cases of rheumatic fever were clustered in two predominantly non-white low income areas of the city, suggesting that preventive efforts could be effectively implemented by primarily directing them to these high risk districts. The Jones criteria were not met in 20 per cent of patients discharged from Baltimore hospitals with a diagnosis of acute rheumatic fever. In 84 per cent of these, no major manifestation was present and the diagnosis apparently resulted from undue diagnostic emphasis being placed on acute phase reactants and elevated anti-streptolysin 0 titers. This suggests that effective programs of physician education could well reduce the frequency of overdiagnosis of rheumatic fever.