A.K. Hallway1,4, E. Isenberg5, R. Howard1, S. O’Neill1, J. Shao1, L. Schoel1, M. Rubyan2, A. Ehlers1,3, D.A. Telem1 1University Of Michigan, Department Of Surgery, Ann Arbor, MI, USA 2University Of Michigan, School Of Public Health, Ann Arbor, MI, USA 3Veterans Affairs Ann Arbor Health System, Department Of Surgery, Ann Arbor, MICHIGAN, USA 4University Of Michigan, Department Of Learning Health Sciences, Ann Arbor, MI, USA 5University Of Texas Southwestern Medical Center, Department Of Surgery, Dallas, TX, USA
Introduction: Beginning in 2023, significant CPT coding changes established a hernia size-dependent reimbursement schedule for anterior abdominal hernia repair. Prior to this policy change taking effect, hernia size was not relevant in payment for hernia repair. Given that repairing larger hernias now results in greater reimbursement relative to smaller hernias, the following study examines whether this 2023 policy change was associated with changes in the average reported size of repaired hernias.
Methods: An interrupted time series analysis was conducted using a population-representative statewide clinical data registry to examine average physician-reported hernia size before and after the 2023 CPT coding changes took effect. All ventral/incisional hernia cases in the Michigan Surgical Quality Collaborative Core Optimization Hernia Registry (MSQC COHR) performed between Jan 1, 2022-Dec 31, 2023 (1-year pre- and 1-year post-intervention), were included in the analysis. The average weekly hernia size was calculated, and a generalized linear model employing Newey-West errors and zero lags was fit to assess the level and trend of hernia size documentation before and after the 2023 size-dependent coding changes took effect. A washout period was imposed one month before and one month after the policy change took effect. Autocorrelation was evaluated using the Cumby-Huizinga test for autocorrelation.
Results: A total of 9,540 cases were included in analysis, with 4,666 (48.9%) in the preintervention group and 4,864 (51.1%) in the post intervention group. The average (SD) age of the entire cohort was 54.8 (14.4) years and 4,127 (43.3%) of the cases were performed on females. The average (SD) hernia size before the 2023 policy change was 3.19 cm (3.28), and it was 3.54 cm (3.34) in the year after. Interrupted time series analysis revealed there was a .40 cm change in the average hernia size documented after the policy change took effect (P = .020 [95% CI =.06 – .73]). There was no significant trend in average hernia size documentation in the preintervention period (β = .001, P = .948 [95% CI = -.029 – .031]), nor was there a significant trend in the post intervention period (β = -.01, P = .567 [95% CI =.-.048 – .027]).
Conclusion: The 2023 changes in anterior abdominal hernia repair CPT coding, which established a hernia size-dependent reimbursement schedule, were associated with an near immediate increase in average documented hernia size by clinicians. This associated change may be the result of improved documentation accuracy as financial incentive elevated the importance of proper measurement, or it may reflect changes in patient selection or measurement bias as operating on larger hernias would result in greater reimbursement.