Effect of the November 2023 Medicare Benefits Schedule PSA Testing Reform on National Utilisation, Diagnostic Activity, and Health-System Expenditure in Australia

Background/Objectives: On 1 November 2023, the Medicare Benefits Schedule (MBS) introduced major reforms to prostate-specific antigen (PSA) testing in Australia, extending the minimum re-test interval for average-risk men (item 66655) from 12 to 23 months and introducing a new annual high-risk item (66654). These changes were aimed at reducing overscreening, aligning practice with national guidelines, and improving cost efficiency; however, their real-world impact on PSA utilisation, downstream diagnostic activity, and health-system costs has not been evaluated. Methods: We performed a national, population-level analysis of all reimbursed PSA tests (items 66655 and 66654) and prostate magnetic resonance imaging (MRI) scans (item 63541) from November 2021 to October 2025 using MBS claims data. Monthly utilisation trends were examined descriptively and modelled using interrupted time-series segmented regression with Newey–West heteroscedasticity- and autocorrelation-consistent standard errors. Economic impacts were estimated using schedule fees. MRI trends were assessed to explore early signals of downstream diagnostic change. Results: Prior to the reform, average-risk PSA testing (item 66655) averaged 61,704 claims per month (median 62,526). After November 2023, utilisation fell immediately to 49,620 and stabilised at a lower mean of 44,702 claims per month (median 43,495), representing a sustained 27.6 percent reduction. High-risk PSA testing (item 66654) accounted for 130,739 claims post-reform (10.9 percent of monthly post-reform PSA activity), but the increase in high-risk testing did not offset the reduction in average-risk claims; total PSA claims fell from 61,704 to 50,149 per month (−18.7 percent). Interrupted time-series modelling confirmed a large, significant step decrease for item 66655 (−23,191 claims, 95% confidence interval (CI) −31,215 to −15,167; p < 0.001) and for total PSA testing (−16,876 claims, 95% CI −25,899 to −7853; p < 0.001). In contrast, prostate MRI utilisation increased from 3854 to 4454 monthly scans (+15.6 percent) with no significant step-change at the time of the reform (p = 0.74) but a significant acceleration in post-reform growth (+49 scans/month, p = 0.0095). The reform resulted in an estimated net saving of $2.8 million in annual PSA expenditure. Conclusions: The November 2023 MBS reforms led to a large, immediate, and durable reduction in reimbursed PSA screening among average-risk men, while high-risk testing increased modestly but remained proportionally small. Total PSA testing declined meaningfully, producing substantial cost savings for Medicare. Rising MRI utilisation indicates that downstream diagnostic activity did not fall in parallel with reimbursed PSA claims, though this trend may reflect independent drivers of MRI growth rather than preserved screening vigilance. Reductions varied by jurisdiction, with two smaller jurisdictions showing net increases over the study window, underscoring that the national pattern was not uniform.