Hypospadias prevalence by severity and associated risk factors: A population-based active surveillance analysis

Hypospadias is one of the most common congenital anomalies. Trends of hypospadias prevalence by severity are not well reported. Most prevalence studies consist of pooled data from different countries or states suffer from low data quality due to inconsistent methodologies, limited variables, and lack of categorization of hypospadias severity.

The objective of this study is to examine the prevalence of hypospadias by degrees of severity and associated risk factors using combined data sources from a stable and well-defined population.

The study population includes infants born with hypospadias to mothers residing in Arkansas from 1997 to 2016. Cases were identified from an active population-based surveillance program of birth defects. Identified hypospadias cases from surveillance data were linked to birth certificate and to a clinical database. These two data sources provide more details on the location of the defect and maternal and infant characteristics. The prevalence and 95% confidence intervals were calculated using total male live births as denominator. Chi-square test was used to assess the association of nominal variables. Logistic regression was used to calculate adjusted odds ratio.

A total 3230 hypospadias cases were identified from 1997 to 2016. The overall prevalence is 83.0 per 10,000 male births. A majority of cases (56.7%) were classified as first degree with the others having second degree (22.8%), third degree (4.7%) or not otherwise specified (15.6%). The highest prevalence of hypospadias was observed among Non-Hispanic whites. Higher prevalence also was observed among mothers in the older age group with no prenatal care in the first trimester and with gestational hypertension or diabetes. Premature or small for gestational age infants tend to have higher prevalence across all levels of severity. The number of hypospadias cases increased over time. After maternal age, race and education were adjusted, higher risk persisted for infants of restricted fetal growth, mothers with gestational hypertension or diabetes and the cohort of 2013-2016.

There is an increase of hypospadias cases in Arkansas. Several maternal and infant characteristics associated with higher prevalence for all levels of severity are worth further investigation.