Purpose: Epidemiologic studies have suggested that the incidence of congenital penile anomalies (CPA), particularly hypospadias, is increasing. This phenomenon has significant biological and socioeconomic implications. We sought further confirmation of the reported trends using a large national database.
Materials and methods: The Nationwide Inpatient Sample is a 20% sample of United States hospitals containing data on 5 to 7 million hospital inpatient stays per year. We identified male newborns, used ICD-9 codes to identify newborns with CPA, determined nationally weighted incidence over time and performed multivariate analyses to identify factors associated with CPA.
Results: Of the 4.84 million male newborns in the Nationwide Inpatient Sample we identified 37,577 with CPA (weighted incidence rate 7.8/1000 newborns). The weighted incidence increased from 7.0/1000 newborns in 1988 to 1991 to 8.3/1000 in 1997 to 2000 (p <0.0001). The most common diagnosis was hypospadias (68.3%), followed by chordee (8.6%) and hypospadias plus chordee (5%). Unspecified genital or penile anomalies were reported for 14% of the cases. The highest incidence of CPA was in white newborns (9.2/1000), followed by black newborns (7.5/1000), Asians (5.0/1000) and Hispanics (4.7/1000) (p <0.0001). Socioeconomic status (SES) was strongly associated with CPA, with CPA odds 19% higher for the highest SES category versus the lowest (OR 1.18, 95% CI 1.16-1.20). Increasing incidence of CPA over time was observed even after adjusting for race/ethnicity, geographic region, insurance status and SES.
Conclusions: These nationally representative, weighted analyses reveal a significant increase in the incidence of CPA, with striking variation by race, region and SES. Further research into potential causes, as well as the observed disparities in incidence, is needed.