Mary Mahieu, M.D.
Rheumatology Physician · Chicago, IL
Mary Mahieu, M.D. is a rheumatology physician with a practice address in Chicago, Illinois, and NPI 1811218381, issued on Jun 18, 2010. Check the license (Illinois 036131440, as entered in NPPES) on the Illinois Department of Financial and Professional Regulation; the Medicare figures below come from public CMS files.
- Name
- Mary Mahieu
- Credential
- M.D.
- Primary taxonomy
- Rheumatology Physician 207RR0500X
- License number
- 036131440 IL
Self-reported in NPPES; status is on the state search - Practice location
- 675 N Saint Clair St, Chicago, IL 60611
- Phone
- (312) 695-8628
- Enumerated
- Jun 18, 2010
- Entity
- Type 1 · individual
Also registered at 675 N Saint Clair St
A shared address usually means a shared clinic or building; it does not show who employs whom.
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- Mohammed Alghoul, M.D.Student in an Organized Health Care Education/Training Program1932376746
- Sharon Allen, APRNAdult Health Nurse Practitioner1003849993
Verify Mary Mahieu in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersIllinois Department of Financial and Professional Regulation
Search for license 036131440Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS, AOA, NCCPA, AANPNot checked
50% fewer Medicare Part D claims than the average rheumatology physician in 2024
1,024 Medicare Part D claims for 169 beneficiaries, against an average of 2,058 among the 4,833 providers of this specialty who prescribed in Part D. Brand-name drugs were 14% of claims.
Most prescribed
- Hydroxychloroquine Sulfate228 claims
- Prednisone128 claims
- Methotrexate91 claims
- Mycophenolate Mofetil35 claims
- Azathioprine34 claims
- Humira(Cf) Pen34 claims
Source: CMS Medicare Part D Prescribers by Provider and Drug, 2024 (data.cms.gov). Part D covers prescriptions for Medicare patients only; drugs with fewer than 11 claims are not published.
The Medicare quality score for 2023: 94.1 of 100
The Merit-based Incentive Payment System score is reported for this clinician. Four categories are weighted into the final score; the average among 454,083 clinicians with a measured score was 83.5.
Source: CMS Quality Payment Program, MIPS performance year 2023; category weights for 2023 (qpp.cms.gov).
One hospital or facility affiliation
- Northwestern Medical Faculty FoundationEvanston, IL
Source: CMS Doctors and Clinicians affiliations; Hospital General Information (Care Compare) (data.cms.gov). Star ratings are CMS hospital ratings, not ratings of this provider.
Rheumatology Physician providers in Illinois
There are 267 rheumatology physician records in Illinois.
Other rheumatology physician records in Illinois
- Elaine Adams, MDMaywood, IL1699752592
- Emem Adolf-Ubokudom, M.D.Chicago, IL1861780603
- Shri Agrawal, M.D.Chicago, IL1912937178
- Umber Ahmad, DOMcHenry, IL1083957153
- Saba AhmedChicago, IL1861448003
- Harpinder Ajmani, M.D.Chicago, IL1720101066
- Iqbal Akhter, M.D.Mount Vernon, IL1083719991
- Ibrahim Alghafeer, MDSycamore, IL1669444709
- Monica Aloman, MDChicago, IL1134236789
- Casey Aman, MDChicago, IL1891435582
Common questions
What is Mary Mahieu, M.D.'s NPI number?
Mary Mahieu, M.D.'s National Provider Identifier (NPI) is 1811218381, issued on Jun 18, 2010. An NPI identifies a provider in billing; it is not a license.
Where is Mary Mahieu, M.D. located?
The NPPES record lists a practice address at 675 N Saint Clair St, Chicago, IL, 60611. Phone: (312) 695-8628. Providers update this record themselves, so call before visiting.
How can I verify Mary Mahieu, M.D.'s license?
NPPES lists Illinois license number 036131440, as entered by the provider. Search the Illinois Department of Financial and Professional Regulation at https://idfpr.illinois.gov/checklicense.html. The NPPES record confirms identity only; the state search shows license status, expiration and public orders.
How much does Mary Mahieu, M.D. prescribe under Medicare Part D?
In 2024, Mary Mahieu, M.D. had 1,024 Medicare Part D claims for 169 beneficiaries; the average among rheumatology physician prescribers was 2,058. Part D covers Medicare prescriptions only.
What is Mary Mahieu, M.D.'s Medicare quality score?
The 2023 MIPS final score is 94.1 of 100. The average among 454,083 clinicians with a measured score was 83.5.
Source: CMS National Plan and Provider Enumeration System (NPPES), loaded Aug 27, 2026 (NPPES files on CMS.gov); NUCC Health Care Provider Taxonomy. Medicare files from data.cms.gov. An NPI identifies who bills; it is not a license.
Every figure on PlainDoctor is rendered directly from the federal CMS NPPES registry, Medicare Part D, MIPS, and Open Payments records, no number is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of Aug 27, 2026.