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Sex differences in care complexity and cost of cardiac-related procedures as a basis for improving hospital payments systems

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In this study, we estimate sex differences in care complexity and cost of cardiac-related procedures in order to demonstrate the importance of sex as a risk adjuster in a hospital payment system. We use individual visit-level data for all adult Israelis who underwent either heart valve surgery (HVS) or coronary artery bypass graft surgery (CABG) during the period 2014–2018 in publicly funded hospitals. We find that women undergoing a cardiac-related procedure are more likely to die during hospitalization, they have longer hospital stays, and overall, they are more likely to be care-complex than men. Furthermore, the cost of the surgery itself is higher for women than for men in the case of HVS (though not CABG), and the cost of the post-operative hospital stay is higher in the case of CABG (though not HVS). It is concluded that sex differences should be considered in the calculation of payment for cardiac-related procedures in order to reduce incentives for selection and reduce unwarranted variation in cardiac-care utilization and medical practice.

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The study was funded with the assistance of the Government of Israel and the Myers-JDC-Brookdale Institute. We are grateful to John Armstrong, Konstantin Beck, John Bertko, Sylvia Demme, Rudy Douven, Randy Ellis, Jacob Glazer, Lukas Kauer, Thomas McGuire, Sonja Schillo, Erik Schut, Christian Schmid, Maria Trottmann, Wynand Van de Ven, Juergen Wasem, and participants in the Risk Adjustment Network 2021 Annual Meeting (in Weggis, Switzerland) for helpful comments and discussion. We also thank Merav Kaplan at the Myers-JDC-Brookdale Institute for her initial work on data curation and Prof. Bruce Rosen for his comments on the final draft. We also thank Yaacov Diskin, Senior information Analyst at HMC, and to the Information Division of the Israeli Ministry of Health for the initial contracting and de-identifying of the datasets.

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Authors and Affiliations



SB-G contributed to conceptualization, methodology, software, formal analysis, data curation, writing—original draft, writing—review and editing, and visualization. SF contributed to methodology, software, formal analysis, writing—original draft, writing—review and editing, and visualization. NS contributed to conceptualization, data curation, and writing—review and editing. YW contributed to conceptualization, data curation, and writing—review and editing.

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Correspondence to Shuli Brammli-Greenberg.

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The authors declare that they have no conflicts of interest. The views presented here are those of the authors and not necessarily those of the Israeli Ministry of Health, its directors, officers or staff.

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Appendix 1

Case complexity variables by sex and procedure

The analysis in this appendix is based on the national database. The differences between men and women were tested for two case complexity variables: age and Charlson score. It was found that on average the CABG patients are older than the heart valve surgery patients with higher Charlson scores. On average, women are older than men (2 years in the case of the heart valve procedure and 4 years in the case of CABG). However, while women have lower average Charlson scores in the heart valve procedure, they have higher scores in the CABG procedure (Table 2.1). The Kolmogorov–Smirnov tests reject the Null Hypothesis that the distribution of age and Charlson score are the same for men and women in both procedures (See Table

Table 7 Case complexity variables by sex and procedure; mean (SD)


Care complexity variables by sex and procedure

See Table

Table 8 Care complexity variables by sex and procedure


Actual cost variables by sex and procedure

See Table

Table 9 Actual cost variables (log10) for heart valve surgery or CABG, B(CI)


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Brammli-Greenberg, S., Fialco, S., Shtauber, N. et al. Sex differences in care complexity and cost of cardiac-related procedures as a basis for improving hospital payments systems. Eur J Health Econ 24, 539–556 (2023).

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