Risk of Hydroceles Following Pyeloplasty

This population-based study will use provincial health administrative data to examine the risk of hospital admission for hydrocelectomy among males who underwent laparoscopic pyeloplasty, compared with males from the general population with similar baseline health characteristics. We will use health administrative data from Ontario, Canada, to identify males who had a laparoscopic pyeloplasty between 2002 and 2024. We will calculate a propensity score based on sociodemographic characteristics, comorbidities, and health care utilization. We will then match laparoscopic pyeloplasty males to non-pyeloplasty male controls (1:10) based on propensity score, age, and index date. The primary outcome is hospital admission for hydrocelectomy. The secondary outcomes are a hydrocele diagnosis and receipt of a scrotal ultrasound.

\*Laparoscopic Pyeloplasty Cohort\* Inclusion Criteria: This cohort will include male individuals who underwent a laparoscopic pyeloplasty between April 1, 2002, and March 31, 2024. For patients who have undergone more than one pyeloplasty, only the first procedure will be considered. Exclusion Criteria: * Individuals with data record errors (e.g., missing or invalid age, sex, or date of birth), who are less than 0 years of age or greater than 105 years of age, with a death record on or before their cohort entry, or are non-Ontario residents or are OHIP ineligible on the index date (to restrict to permanent residents of the province). * Anyone who had laparoscopic surgery to open surgery for pyeloplasty in the same index * Previous scrotal or genital conditions or procedures (includes cancers, hydroceles, scrotal ultrasounds, etc.) * Long-term care resident * Any evidence of chronic dialysis * No physician visits in the year prior to cohort entry \*Non-Pyeloplasty Control Cohort\* Inclusion Criteria: The control cohort will consist of male individuals identified in the RPDB (the general Ontario population). Index dates will be randomly assigned by bootstrapping dates from the pyeloplasty group, such that each control is assigned an actual pyeloplasty index date randomly sampled with replacement from that group. Controls will be carefully screened to ensure that none are included in the pyeloplasty cohorts. Exclusion Criteria: * Individuals with data record errors (e.g., missing or invalid age, sex, or date of birth), who are less than 0 years of age or greater than 105 years of age, with a death record on or before their cohort entry, or are non-Ontario residents or are OHIP ineligible on the index date (to restrict to permanent residents of the province). * Any evidence of previous pyeloplasty surgeries * Previous scrotal or genital conditions or procedures (includes cancers, hydroceles, scrotal ultrasounds, etc.) * Long-term care resident * Any evidence of chronic dialysis * No physician visits in the year prior to cohort entry \*Open Pyeloplasty Cohort\* Inclusion Criteria: The open cohort will include male individuals who underwent an open pyeloplasty between April 1, 2002, and March 31, 2024. For patients who have undergone more than one pyeloplasty, only the first procedure will be considered. Exclusion Criteria: * Individuals with data record errors (e.g., missing or invalid age, sex, or date of birth), who are less than 0 years of age or greater than 105 years of age, with a death record on or before their cohort entry, or are non-Ontario residents or are OHIP ineligible on the index date (to restrict to permanent residents of the province). * Anyone who had laparoscopic surgery to open surgery for pyeloplasty in the same index * Previous scrotal or genital conditions or procedures (includes cancers, hydroceles, scrotal ultrasounds, etc.) * Long-term care resident * Any evidence of chronic dialysis * No physician visits in the year prior to cohort entry