Methods The Kids’ Inpatient Database (KID) is a national, all-payer database of 2-3 million inpatient pediatric hospitalizations per year, including both complicated and uncomplicated in-hospital births, at up to 4,121 hospitals in 44 states. We reviewed KID to evaluate the birth prevalence of spina bifida, posterior urethral valves, bladder exstrophy, epispadias, prune belly syndrome, ambiguous genitalia, and imperforate anus among in-hospital births. For posterior urethral valves and prune belly syndrome, we limited our search to newborn males only. We used ICD-9 diagnostic codes to identify patients in the 1997, 2000, 2003, 2006, and 2009 KID (with the exception of prune belly, for which 1997 was not used due to ICD-9 coding changes). Poisson regression models were used to estimate trends in birth prevalence over time.
Results During the study period, 4.5 million in-hospital births were captured by the KID database. Of these, 3,413 newborn infants were diagnosed with spina bifida, 214 with bladder exstrophy, 1,127 with epispadias, 726 with ambiguous genitalia, 180 with prune belly syndrome, 578 with posterior urethral valves, and 4,040 with imperforate anus. We identified no significant changes in the birth prevalence of spina bifida (from 33.9 new spina bifida births/100,000 uncomplicated in-hospital births in 1997 to 29.0/100,000 in 2009, p=0.08), posterior urethral valves (10.4-11.0/100,000, p=0.51), prune belly syndrome (4.8-3.3/100,000, p=0.44), or ambiguous genitalia (5.82-5.87/100,000, p=0.38). However, there was a significant decrease in birth prevalence of bladder exstrophy (2.4-1.6/100,000, p=0.01) and a significant increase in epispadias (8.0-11.6/100,000, p=0.04) and imperforate anus (33.6-35.0/100,000, p=0.04) during the study period.
Conclusion The birth prevalence of spina bifida, posterior urethral valves, prune belly syndrome, and ambiguous genitalia appear to be stable over the last 12 years. Epispadias and imperforate anus have been more commonly diagnosed in newborns over the same time period, while bladder exstrophy has been less commonly diagnosed in newborns.
| Year | Spina Bifida | Exstrophy | Epispadias | Intersex | Imperforate Anus | Prune Belly | Posterior Urethral Valves |
| 1997 | 33.93 | 2.35 | 7.95 | 5.82 | 33.58 | - | 10.39 |
| 2000 | 27.86 | 1.75 | 7.69 | 6.38 | 32.44 | 4.77 | 9.10 |
| 2003 | 26.84 | 1.76 | 8.75 | 5.36 | 32.40 | 3.23 | 9.02 |
| 2006 | 26.62 | 1.58 | 9.64 | 5.67 | 33.06 | 3.32 | 8.24 |
| 2009 | 29.01 | 1.63 | 11.58 | 5.87 | 34.98 | 3.28 | 11.02 |