Contemporary epidemiology of bladder exstrophy in the United States

Although bladder exstrophy is much discussed in the urology literature, there are few population based epidemiological data available for this rare condition. The purpose of this study was to use a large nationwide database to collect contemporary data on the incidence and demographics of bladder exstrophy.

The Healthcare Cost and Utilization Project Nationwide Inpatient Sample is a 20% sample of nonfederal United States hospitals containing data on 5 million to 7 million inpatient stays per year. The sample was limited to newborns, and International Classification of Disease-9 codes were used to identify cases of bladder exstrophy. We then determined nationally weighted incidence through time, and performed multivariate analyses to identify factors associated with exstrophy.

We identified 205 patients with exstrophy among 9,452,110 newborns. The overall weighted incidence of exstrophy was 2.15 per 100,000 live births. The male-to-female ratio was almost even (OR 0.989, 95% CI 0.88 to 1.12). White infants were significantly more likely to present with exstrophy than nonwhites (incidence 2.63 vs 1.54 per 100,000, p <0.0001). Exstrophy incidence also varied by geographic region, socioeconomic status (SES) and insurance status. On multivariate analysis the racial variation in exstrophy incidence persisted even after adjustment for geographic region, SES and insurance status. Conditions such as spina bifida, cleft palate, preterm birth and gastrointestinal anomalies were more common in newborns with exstrophy.

Bladder exstrophy is rare, occurs in equal numbers of live male and female newborns, and is associated with certain co-morbid conditions. Incidence appears to be stable through time. Nonwhite race, uninsured status, high or low SES and Western geographic region are associated with lower exstrophy incidence.