INTRODUCTION: The purpose of this study was to present a nationwide cumulative incidence and an age-specific incidence rate of groin hernia repair as well as to evaluate the validity of inguinal and femoral hernia operation codes in the Danish National Patient Registry (DNPR). METHODS: All persons born in Denmark from 1977 to 2010 were investigated for groin hernia operations registered in the DNPR with respect to date of admission, operation, discharge and specific operation codes. To validate the predictive values of registrations, we randomly extracted data on elective and emergency groin hernia operations from the DNPR from 2005 to 2010 and examined the medical records. RESULTS: The study population (n = 2,109,417) from 1977 to 2010 was followed from the primary groin hernia operation (n = 53,262) to 2010, yielding a total of 33.4 million person-years of follow-up. The probability of being operated for a groin hernia prior to the age of 34 years was 5.70% (95% confidence interval (CI): 5.62-5.78) for males and 1.26% (95% CI: 1.20-1.32) for females. The highest incidence rate was seen among males aged 0-1 years (10.19 (95% CI: 10.00-10.38)). The positive predictive value of patients registered with inguinal hernia operations in the DNPR who had been operated for an inguinal hernia was 100% (95% CI: 96-100%) and 91.3% (95% CI: 83-96%) for femoral hernia operations. CONCLUSIONS: The incidence rate of groin hernia operations peaked at the 0-1 year age group in males and at the 3-4-year age group in females. Furthermore, the validation of the DNPR showed very high positive predictive values for both inguinal hernia operations and femoral hernia operations. FUNDING: none. TRIAL REGISTRATION: not relevant.
INTRODUCTION: The purpose of this study was to present a nationwide cumulative incidence and an age-specific incidence rate of groin hernia repair as well as to evaluate the validity of inguinal and femoral hernia operation codes in the Danish National Patient Registry (DNPR). METHODS: All persons born in Denmark from 1977 to 2010 were investigated for groin hernia operations registered in the DNPR with respect to date of admission, operation, discharge and specific operation codes. To validate the predictive values of registrations, we randomly extracted data on elective and emergency groin hernia operations from the DNPR from 2005 to 2010 and examined the medical records. RESULTS: The study population (n = 2,109,417) from 1977 to 2010 was followed from the primary groin hernia operation (n = 53,262) to 2010, yielding a total of 33.4 million person-years of follow-up. The probability of being operated for a groin hernia prior to the age of 34 years was 5.70% (95% confidence interval (CI): 5.62-5.78) for males and 1.26% (95% CI: 1.20-1.32) for females. The highest incidence rate was seen among males aged 0-1 years (10.19 (95% CI: 10.00-10.38)). The positive predictive value of patients registered with inguinal hernia operations in the DNPR who had been operated for an inguinal hernia was 100% (95% CI: 96-100%) and 91.3% (95% CI: 83-96%) for femoral hernia operations. CONCLUSIONS: The incidence rate of groin hernia operations peaked at the 0-1 year age group in males and at the 3-4-year age group in females. Furthermore, the validation of the DNPR showed very high positive predictive values for both inguinal hernia operations and femoral hernia operations. FUNDING: none. TRIAL REGISTRATION: not relevant.