Seasonality of Common Pediatric Infectious Diseases.

Background/objective: Traditional sources cite seasonal patterns for common infectious diseases, often based on microbiologic data, but little is known about cyclical trends in clinically diagnosed infectious conditions in the emergency department (ED). We leveraged the publicly available Nationwide Emergency Department Sample database to measure the seasonality of the most common pediatric infectious diseases diagnosed in US EDs.

Methods: We searched the Nationwide Emergency Department Sample database to identify infectious diagnoses comprising at least 1% of all diagnosis codes ascribed to patients 21 years and younger in US EDs from 2009 to 2013. We used Fourier regression to examine seasonal trends in disease and calculated the peak-to-nadir ratio for each infectious condition.

Results: Over 20% of pediatric visits during the study period were for infectious conditions. Upper respiratory infection, otitis media, gastroenteritis, urinary tract infection/pyelonephritis, cellulitis/abscess, and pneumonia showed a seasonal pattern that matched trends found in prior regional or microbiologic-based studies. The strongest seasonal trend as measured by goodness of model fit was found in pneumonia (peak-to-nadir incidence ratio of 2.7), followed by otitis media (2.0), cellulitis/abscess (2.0), gastroenteritis (1.6), upper respiratory infection (3.2), and urinary tract infection/pyelonephritis (1.4). Pharyngitis did not show a strong seasonal trend.

Conclusions: Many of the most common pediatric infectious diseases diagnosed in US EDs exhibited seasonal patterns. Large administrative databases can be used to track seasonal disease patterns, with the advantage that they reflect clinician diagnosis beyond microbiologic confirmation. This methodology could aid in resource planning, infection control, and public health educational initiatives.