PERTUSSIS HOSPITALIZATIONS AND MORTALITY IN THE UNITED-STATES, 1985-1988 - EVALUATION OF THE COMPLETENESS OF NATIONAL REPORTING

Objective. - To determine the magnitude of hospitalizations for pertussis and pertussis mortality and to estimate the total burden of clinically significant pertussis in the United States. Design. - Capture-recapture methods for estimating population size from independent surveillance systems were used to analyze morbidity and mortality data from case report forms received at the Centers for Disease Control (CDC) from the states, and compared these data with pertussis hospitalizations compiled from a database of US hospitals participating in the Commission on Professional and Hospital Activities-Professional Activities Survey (CPHA-PAS) and death certificate reports compiled by the National Center for Health Statistics (NCHS). Population Studied. - All pertussis hospitalizations and pertussis-related deaths in the United States, 1985 through 1988. Results. - We estimated that 13 557 pertussis hospitalizations (95% confidence interval [CI], 12953 to 14162) and 98 pertussis deaths had occurred during the 4-year study period (an average of more than 3300 hospitalizations and 25 deaths per year). The completeness of reporting hospitalizations to the CDC was 32% and to the CPHA-PAS, 23%, while the completeness of reporting pertussis deaths to the CDC was 33% and to NCHS, 23%. Patients who were hospitalized with per-tussis and reported to CDC were at a higher risk for developing pneumonia (31.0% vs 20.0%, relative risk [RR], 1.6; 95% CI, 1.4 to 1.7), seizures (3.7% vs 2.1 %; RR, 1.9; 95% CI, 1.4 to 2.5) and encephalitis (1.2% vs 0.2%; RR, 5.3; 95% CI, 2.4 to 11.6) compared with patients recorded in the CPHA-PAS system. Conclusions. - Our study suggests that there is substantial underreporting of pertussis, that severe complications of pertussis (including hospitalizations) are reported preferentially to the CDC, and that the national health impact of pertussis based on these indicators is considerably higher than previously published reports have suggested.