UNDERSTANDING NIH CLINICAL CASE DEFINITIONS FOR PEDIATRIC INTRATHORACIC TB BY APPLYING THEM TO A CLINICAL TRIAL

SETTING AND OBJECTIVE: Currently, standardized clinical case definitions represent the best option for pediatric tuberculosis (TB) disease diagnosis and classification. We applied clinical case definitions for intrathoracic TB classification, developed by an expert panel for use in reporting diagnostic studies with passive case finding, to TB suspects from IMPAACT P1041, a trial of INH prophylaxis in healthy HIV-exposed, BCG vaccinated infants which employed active surveillance, to assess novel application of these guidelines in this setting. METHODS: P1041 TB suspects were retrospectively cross-classified by protocol-defined and NIH classifications and agreement assessed. RESULTS: Of 219 TB suspects, 166 had signs/symptoms (S/S), with 158 considered TB (21 confirmed, 92 probable, 45 possible) and 8 not TB (6 TB unlikely, 2 alternative diagnoses). Weight loss and failure to thrive represented the majority of observed S/S. Among those with S/S, agreement between definitions was poor. Additionally, 53 TB suspects were without S/S, including 33 classified by the P1041 protocol as TB. CONCLUSION: The poor agreement between P1041 and NIH classifications reflects cases that are identified through active versus passive surveillance, the latter reflecting the intended use of NIH definitions. Given the interest in having standardized definitions for broader application, future efforts could focus on expanding TB disease classification for detection and classification of suspects identified through active surveillance