Bladder exstrophy: an epidemiologic study from the International Clearinghouse for Birth Defects Surveillance and Research, and an overview of the literature

Abstract

Bladder exstrophy (BE) is a complex congenital anomaly characterized by a defect in the closure of the lower abdominal wall and bladder. We aimed to provide an overview of the literature and conduct an epidemiologic study to describe the prevalence, and maternal and case characteristics of BE. We used data from 22 participating member programs of the International Clearinghouse for Birth Defects Surveillance and Research (ICBDSR). All cases were reviewed and classified as isolated, syndrome, and multiple congenital anomalies. We estimated the total prevalence of BE and calculated the frequency and odds ratios for various maternal and case characteristics. A total of 546 cases with BE were identified among 26,355,094 births. The total prevalence of BE was 2.07 per 100,000 births (95% CI: 1.90-2.25) and varied between 0.52 and 4.63 among surveillance programs participating in the study. BE was nearly twice as common among male as among female cases. The proportion of isolated cases was 71%. Prevalence appeared to increase with increasing categories of maternal age, particularly among isolated cases. The total prevalence of BE showed some variations by geographical region, which is most likely attributable to differences in registration of cases. The higher total prevalence among male cases and older mothers, especially among isolated cases, warrants further attention.

Figure 1

Total prevalence of bladder exstrophy per 100,000 births (bar) and 95% confidence interval (line) by surveillance program, and overall prevalence (dotted line), in 22 surveillance programs of the International Clearinghouse for Birth Defects Surveillance and Research (ICBDSR).

Figure 2

Prevalence ratios for maternal age groups relative to the reference age of <20 years with corresponding 95% CIs for bladder exstrophy in 22 surveillance programs of the International Clearinghouse for Birth Defects Surveillance and Research (ICBDSR). Chi square for trend = 16.23; P <0.01.

Figure 3

Prevalence ratios for maternal age groups by isolated and multiple congenital anomalies (MCA) cases relative to the reference age of <20 years with corresponding 95% CIs for bladder exstrophy in 22 surveillance program members of the International Clearinghouse for Birth Defects Surveillance and Research (ICBDSR). Isolated cases: Chi-square for trend = 20.77; P <0.01. MCA cases: Chi-square for trend = 0.18; P = 0.67.