Volume Matters: Longitudinal Retrospective Cohort Study of Outcomes Following Consultation and Standardization of Adrenal Surgery

Ann Surg Oncol. 2021 Dec;28(13):8849-8860. doi: 10.1245/s10434-021-10297-3. Epub 2021 Jun 17.


Purpose: Subspecialization of adrenal surgery through regionalization has not been adequately evaluated. We assessed implementation of subspecialization and the association of regionalization with adrenalectomy outcomes in a community-based setting.

Methods: In this longitudinal retrospective cohort study, we used an interrupted time series analysis on consecutive adrenal surgeries at Kaiser Permanente Northern California, 2010-2019. The intervention was regionalization of surgery in 2016. Main outcomes include surgical volumes, operative time, length of stay, 30-day return-to-care, and 30-day complications obtained from the electronic medical record. t-Tests and multivariable models were used to analyze time trends in outcomes after accounting for changes in patient and disease characteristics.

Results: In total, 850 adrenal surgery cases were eligible. Between 2010 and 2019, the annual incidence of surgery (per 100,000 persons) increased from 2.4 (95% CI 1.9-3.1) to 4.1 (95% CI 3.5-4.8). Average annual surgeon volume increased from 2.4 (95% CI 1.6-3.1) to 9.9 (95% CI 4.9-14.9), while hospital volume increased from 3.5 (95% CI 2.3-4.6) to 15.4 (95% CI 6.9-24.0). Operative time was 34 (23-45) min faster in 2018-2019 compared with 2010-2011. After regionalization, same-day discharges increased to 64% in 2019 (p < 0.0001). The frequency of return-to-care (p = 0.69) and the overall complication rate (p = 0.31) did not change.

Conclusions: Regionalizing adrenal surgery through surgical subspecialization and standardized care pathways was feasible and decreased operative time, and hospital stay, while increasing the frequency of same-day discharges without increasing return-to-care or complications.

MeSH terms

  • Adrenalectomy*
  • Humans
  • Length of Stay
  • Reference Standards
  • Referral and Consultation*
  • Retrospective Studies