Risk of Rheumatic-Fever Recurrences after Streptococcal Infections

The rheumatic-fever recurrence rate per streptococcal infection was studied in 393 patients in whom 711 streptococcal infections and 123 recurrences developed. Factors were evaluated for their relation to the recurrence rate by means of statistical technics that allowed testing the significance of a given factor while holding the others constant; thus, each factor was evaluated independently from the others. Symptoms of pharyngitis (sore throat and fever) were significantly associated with a high recurrence rate, whereas magnitude of rise in antistreptolysin-O titer was not. Young age and, particularly, short interval since the preceding rheumatic attack, were also significantly associated with a high rate of recurrence, as were existing rheumatic heart disease, number of previous attacks and oral (rather than parenteral) administration of drug prophylaxis. The effects of overcrowding, yearly family income, welfare status, rheumatic fever in siblings and ethnic group were not significant.