Variation in the practice of cholecystectomy for benign biliary disease in Aotearoa New Zealand: a population-based cohort study

Is No difference a good outcome? Equity evaluation of the general surgery prioritization tool

BACKGROUND

The general surgery prioritization tool (GSPT) was implemented in 2018 to equitably prioritize non-cancer elective general surgery waitlists. It combines patient-reported Impact On Life (IOL) scores and clinician-reported values for a total score which determines access to the waitlist. In New Zealand there are inequities in surgical access and outcomes, particularly for Māori, and this study evaluates whether the GSPT may contribute.

METHOD

A retrospective review of general surgery prioritization events at Capital & Coast District Health Board, New Zealand, between May 2018 and August 2022 was conducted. The patient-reported IOL score (6-36), total score (0-100), waitlist access, and time to surgery in days were recorded and analyzed for ethnic, age and gender differences.

RESULTS

4527 events were included. Median IOL score and total score were 20 and 68. 4231 (90.8%) met the waitlist threshold with a median time to surgery of 99 days. Higher average IOL scores were associated with being female (P = 0.005), Pacific Peoples (P = 0.007) and Other Ethnicity (P = 0.006). The average total score for Māori was 1.13 points higher than Europeans (P = 0.013). There was no evidence of associations between the odds of surgery booking and patient age, ethnicity and gender when adjusted for deprivation and procedure type.

CONCLUSION

This study shows that despite differences in the IOL and total scores across ethnicity, no evidence of difference was found in the odds of surgical booking based on patient ethnicity, age or gender. Amendments to weighting of IOL scores and ethnicity score adjustment could be considered to remedy this.

External validation of the CholeS conversion from laparoscopic to open cholecystectomy (CLOC) risk score in Aotearoa New Zealand: a validation study

BACKGROUND

Conversion of laparoscopic cholecystectomy to open is uncommon, but is associated with longer hospital stay and recovery. Prognosticating conversion may aid service planning and provision. We therefore aimed to assess the external validity of the largest risk score for operative conversion.

METHODS

CHOLENZ was a multicentre, prospective, national cohort study of cholecystectomy for benign biliary disease conducted by STRATA, a trainee-led collaborative network. Data were collected from patients undergoing cholecystectomy in New Zealand hospitals between 1 August and 30 October 2021 with 30-day follow-up. The Conversion from Laparoscopic to Open Cholecystectomy (CLOC) score from the CholeS study was assessed for external validity by interrogating its accuracy and calibration in the CHOLENZ dataset.

RESULTS

Of 1162 cholecystectomies started laparoscopically, 20 (1.7%) were converted to open in the CHOLENZ dataset. The CLOC score predicted 2.9% (IQR 1.3%-8.1%) would be converted. Area under the curve was 0.65 (95% 0.51-0.79) and calibration was acceptable with a Hosmer-Lemeshow p value of 0.45; with evidence of tendency to overestimate with interrogation of calibration across a continuous risk profile (intercept 1.27, slope 0.4). Sensitivity analysis with imputed data improved accuracy. Recalibration with the addition of body mass index, and preoperative bilirubin also improved accuracy to 0.86 (95% CI 0.78-0.95).

CONCLUSIONS

The CLOC score in its original form is not generalisable to the Aotearoa New Zealand setting and is therefore not suitable for clinical use in our local setting.

Impact of the COVID-19 pandemic on outcomes of cholecystectomy for acute cholecystitis: a national cohort study

BACKGROUND

The COVID-19 pandemic was associated with significant disruptions to healthcare provision globally and in Aotearoa New Zealand. It remains unclear how this disruption affected the surgical management of acute cholecystitis and whether there are ongoing impacts.

METHODS

We conducted a secondary analysis of two multicentre cohort studies (CHOLECOVID and CHOLENZ) on patients who underwent cholecystectomy for acute cholecystitis. Participants were categorized into pre-pandemic (September-November 2019), pandemic (March-May 2020), and late-pandemic (August-October 2021) phases. Baseline demographics, clinical management, and 30-day postoperative complications were assessed between phases. Multivariable logistic regression was used to explore the impact of timing of operation on rates of hospital readmission and postoperative complications.

RESULTS

517 participants were included, of whom 85 (16%) were in the pre-pandemic-phase, 52 (10%) were in the pandemic phase, and 380 (73%) were in the late-pandemic phase. Pandemic and late-pandemic phase participants were more comorbid and had higher rates of obesity and deranged blood results than pre-pandemic. After multivariable adjustment, there were no differences in rates of hospital readmission or postoperative complications at 30-day follow-up across phases.

CONCLUSION

The COVID-19 pandemic had minimal impacts on the provision of cholecystectomy for acute cholecystitis in Aotearoa New Zealand. However, patients managed during the COVID-19 pandemic were more comorbid and had higher rates of obesity and elevated inflammatory markers.