CMS Pays More to Male Cardiologists, but the Reasons Why Are Murky

Men bill more and have more unique charges, but even after accounting for this, there remain differences in payments.

CMS Pays More to Male Cardiologists, but the Reasons Why Are Murky

Male cardiologists receive significantly more payments from the US Centers for Medicare & Medicaid Services (CMS) in the inpatient and outpatient settings compared with female cardiologists, according to a new analysis.

They receive, on average, 45% more than women in annual CMS payments for inpatient services and 62% more for services performed in the outpatient setting. In terms of hard numbers, this translates to $24,229 and $62,306 more paid to men in 2016 for inpatient and outpatient services, respectively.

Inbar Raber, MD (Beth Israel Deaconess Medical Center, Boston, MA), who led the study, said the difference in payments is not the result of gender bias in CMS reimbursement but reflects other factors.

“There is no gender discrimination from the side of Medicare in terms of reimbursement between men and women,” Raber told TCTMD. “Per billing code, it’s the exact same for both genders. The difference really comes about from the types and volume of charges submitted, with men submitting higher reimbursed charges and a higher number of charges overall compared with women.”

However, after accounting for the number of charges, unique billing codes, patient characteristics, and physician specialty, among other variables, the pay gap remained. “Even after those adjustments, there persisted a 6% difference in reimbursement for men compared to women,” said Raber.

Fewer Charges, Fewer Unique Codes

Several studies to date have shown there are differences in pay for male and female physicians across medical specialties, including cardiology. One recent analysis showed that over the course of a lifetime, male cardiologists will earn several million dollars more than their female colleagues. Raber pointed out that a growing proportion of revenue for cardiologists stems from treating patients insured by Medicare and/or Medicaid, which led them to investigate if there were any differences in CMS payments to male and female cardiologists. Previous publications have documented gender differences in CMS payments in other specialties, such as radiation oncology and ophthalmology.

In their study, which was published September 8, 2021, in JAMA Cardiology, the researchers assessed payments received and charges submitted in 2016. The analysis captures data from 17,524 cardiologists, of whom 2,312 were women, receiving CMS payments in the inpatient setting and 16,929 cardiologists, of whom 2,151 were women, receiving payments for outpatient services.

Overall, the mean and median reimbursement payments to men were significantly higher than those received by women. In the inpatient setting, men submitted a median of 1,190 charges to CMS compared with 959 from women. In the outpatient setting, male cardiologists submitted a median of 1,685 charges to CMS for reimbursement compared with 870 from women. Men also submitted more unique billing codes to CMS.

Median Amounts by Gender in 2016




P Value

Payment, $










< 0.001

< 0.001

Number of Charges










< 0.001

< 0.001

Number of Unique Billing Codes










< 0.001

< 0.001

Male cardiologists had more years in practice than female cardiologists. In terms of patient characteristics, the individuals that male cardiologists treated were older (both inpatient and outpatient) and also had marginally higher rates of diabetes, hyperlipidemia, hypertension, and ischemic heart disease but lower rates of heart failure. However, female cardiologists still received less reimbursement compared with men even after adjusting for the number of charges submitted, number of unique billing codes submitted, complexity of patients, physician experience (years since graduation), and physician subspeciality.

When researchers stratified physicians by quintiles based on the number of CMS charges submitted in the inpatient setting, there were significant differences in the median payments favoring men across all charge groups. There was no difference in median CMS payments between men and women within each charge group in the outpatient setting, however. 

Finally, they performed a sensitivity analysis and excluded interventional cardiologists and electrophysiologists, because these are high-volume subspecialties with greater gender imbalances than in general cardiology. After doing so, the differences in CMS payments persisted, say the researchers. And even when physicians were categorized by general cardiology, interventional cardiology, and electrophysiology practicing in the inpatient and outpatient setting, men received higher mean CMS payments compared with women.

Why Are Women Billing Less?  

Rashmee Shah, MD (University of Utah School of Medicine, Salt Lake City), who has previously shown that female cardiologists will earn $2.5 million less than male cardiologists over a 35-year career, said the new analysis is a fascinating look at the differences in reimbursement.

“For Medicare, women cardiologists bill less in the fee-for-service program and accordingly they receive less payments. That’s not too surprising, but why do they bill less is one question,” Shah told TCTMD. It is possible women have different practice and/or billing styles, such as treating more patients covered by Medicare Advantage or private insurance, she suggested. It’s also possible there is less support or fewer resources for women to help with billing, meaning they may be less likely to receive appropriate compensation for services provided.   

Shah said one novel way to view the analysis is to flip it on its head.

“Medicare is going to go bankrupt in 5 years or less,” she said. “Women are billing Medicare less. How are they doing that? Is it beneficial for patients’ outcomes, and if it is, how do we get everyone to do that? Women are saving money for Medicare, and everybody should think that’s a good thing.”

Shah would like to know if there are any differences between men and women with respect to the number of submitted CMS charges per patient. Additionally, she wondered if there is any link between patient outcomes and billing charges. As a corollary, CMS recently posted a job listing for a Chief Experience Officer, she noted.

“This is someone who is, presumably, supposed to focus on patient outcomes and not just outcomes like mortality but: is the patient happy with the care they received?” said Shah. “Do they feel like their questions were answered? Did they understand what the doctor told them? That’s an important thing to measure here. We have to shift the way we do studies to focus on things the patients care about.”

In terms of why there are differences in types and volume of charges submitted, Raber said the study wasn’t designed to address these underlying reasons, but the authors have some hypotheses. For example, women may have increased obligations in nonreimbursed work, such as mentoring, teaching, or serving on committees. Also, it’s possible the lower number of charges submitted by women reflect different practice styles, said Raber. In a 2020 study, for example, researchers showed that female primary-care physicians generated less revenue than men because they had fewer patient visits but spent more time with individual patients.

“In terms of the type of codes submitted, it’s not clear if men are overcoding for certain visits or if women are undercoding for certain patient encounters,” said Raber.

Going forward, she said, it’s important to ensure there is adequate structural support at the institutional level for men and women practicing cardiology, which would include support staff, as well as education on appropriate billing. She suspects this might help narrow the reimbursement gap.

Michael O’Riordan is the Managing Editor for TCTMD. He completed his undergraduate degrees at Queen’s University in Kingston, ON, and…

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  • Raber I, Al Rifai M, McCarthy CP, et al. Gender differences in Medicare payments among cardiologists. JAMA Cardiol. 2021;Epub ahead of print.

  • Raber and Shah reports no conflicts of interest.