Recurrent episodes of acute rheumatic fever may contribute to the development or worsening of rheumatic heart disease. Secondary penicillin prophylaxis (SPP) has been found to significantly reduce the incidence of rheumatic heart disease. This study sought to evaluate adherence to oral and intramuscular SPP in pediatric patients with rheumatic fever using real-world data spanning 10 years.
The study population included patients <18 years old insured by a 2.1-million-member health maintenance organization in Israel who were diagnosed with acute rheumatic fever between 1/1996 and 5/2015 and had purchased at least one monthly dose of oral or intramuscular penicillin by prescription. The mean proportion of days covered by SPP was calculated. The endpoint of the retrospective follow-up for therapy discontinuation was leaving the health maintenance organization, death, age 18 years, or end of follow-up.
The cohort included 842 children: 734 treated with oral penicillin and 108 with intramuscular penicillin. The respective mean (SD) ages of the two groups at diagnosis were 8.6 (3.7) years and 10.9 (3.2) years, and the median (interquartile range) proportions of days covered by SPP were 8% (2%-33%) and 10% (3%-28%). Overall, the number of days covered decreased exponentially from 103 days in the first year of therapy to 20 days in the tenth year of follow-up.
Adherence to SPP for rheumatic fever is poor. This renders this mode of long term prophylaxis futile. Although the IM route has been previously shown to be more effective, the oral route was more extensively used.