National trends in retropharyngeal abscess among adult inpatients with peritonsillar abscess.

OBJECTIVES: To describe national trends in retropharyngeal abscess (RPA) complicating peritonsillar abscess (PTA) and to determine factors associated with RPA in patients with PTA.

STUDY DESIGN: Cross-sectional analysis.

SETTING: Nationwide Inpatient Sample, 2003-2010.

SUBJECTS AND METHODS: PTA patients ≥18 years old, with or without RPA, were extracted according to ICD-9-CM codes. The cohort was analyzed with descriptive statistics and multivariate regression modeling to identify factors associated with RPA.

RESULTS: Of the 91,647 (95% CI: 86,433-95,449) patients identified with PTA, 885 (1.0%) also had a concurrently coded RPA. The annual rate of concomitant RPA increased from 0.5% (95% CI: 0.3%-0.8%) to 1.4% (95% CI: 1.0%-2.0%) between 2003 and 2010 (P < .001). PTA patients with RPA more frequently underwent tonsillectomy (23.5% vs 11.1%), endotracheal intubation (7.1% vs 1.5%), and mechanical ventilation (13.2% vs 2.0%) than those without RPA (all P < .001). PTA patients with RPA were significantly older (41 vs 34 years old), had a longer hospital stay (6.4 vs 2.5 days), and had more procedures (2.5 vs 0.9) when compared to patients without RPA (all P < .001). Upon multivariate regression analysis, factors associated with RPA included the age groups of 40 to 64 years (odds ratio, 2.256; P < .001) and 65 and older (odds ratio, 2.086; P = .045). Median total charges for PTA inpatients with concomitant RPA were approximately $8700 greater (P < .001) when compared to patients with PTA alone.

CONCLUSIONS: The incidence of RPA among adult inpatients with PTA is increasing, and patients with RPA have higher in-hospital resource utilization. Further studies may help validate factors predictive of RPA to enable prevention or earlier identification.