Prevalence, Incidence, and Age at Diagnosis of Boys With Hypospadias: A Nationwide Population-Based Epidemiological Study.

Purpose: The aim of this study was to assess the diagnostic prevalence, incidence, diagnostic age, and surgical volume of hypospadias in Denmark.

Materials and methods: Males with a hypospadias diagnosis in the Danish National Patient Registry (n = 10,276) were identified (1977-2019). A diagnostic algorithm, validated by medical file review (n = 1710), confirmed diagnoses and severity (distal/proximal). The yearly prevalence (live-born hypospadias boys/100,000 newborn boys) and incidence (first hypospadias registration in the Danish National Patient Registry/100,000 boys in background population) were calculated. Age at diagnosis and number of health care contacts were calculated. Poisson regression was used to analyze temporal trends.

Results: Hypospadias was verified in 9189 males (89.4%; distal 8404 [91.5%]; proximal 785 [8.5%]). From 1977 to 2006, the prevalence rose significantly to a mean of 503 (95% CI: 440-565) and peaked at 847 (distal 768, proximal 79) in 2007. From 2008 to 2018, the prevalence stabilized (mean 774, 95% CI: 738-810). A significant rise in incidence was observed. Age at diagnosis decreased from 1977 to 2019. Proximal hypospadias was diagnosed earlier (median 0 years, IQR, 0-0.5) than distal (median 0.2 years, IQR, 0-1.9) and had more (P < 10^-4) nonsurgical hospital contacts (median = 5, IQR, 3-7 vs median = 2, IQR, 1-3). At least 1 surgical admission was recorded for 4550 (58.4%). Boys without surgical admissions (n = 3244, 41.6%) were primarily distal cases (97.7%).

Conclusions: Since 1977, the prevalence of diagnosed hypospadias cases significantly increased and peaked around 800 per 100,000 live boys in 2007. The diagnostic age decreased, proximal cases were diagnosed earlier, and there were more surgical admissions than distal cases. A significant proportion were never operated.