Stuart S. Kassan, MD
Rheumatology Physician · Denver, CO
Stuart S. Kassan, MD is a rheumatology physician with a practice address in Denver, Colorado, and NPI 1093706475, issued on Nov 3, 2005. Check the license (Colorado 21547, as entered in NPPES) on the Colorado Medical Board; the Medicare figures below come from public CMS files.
- Name
- Stuart S. Kassan
- Credential
- MD
- Primary taxonomy
- Rheumatology Physician 207RR0500X
- License number
- 21547 CO
Self-reported in NPPES; status is on the state search - Practice location
- 1400 Jackson St, Denver, CO 80206
- Phone
- (303) 388-4461
- Enumerated
- Nov 3, 2005
- Record last updated
- Jan 4, 2023
- Fax
- (303) 398-1211
- Medicaid ID
- 01215474 CO
- Medicare enrollment
- Enrolled (PECOS I20040206000218); accepts Medicare assignment
- Medical or professional school
- George Washington University School Of Medicine, 1972
- Telehealth
- Offers telehealth (CMS)
- Entity
- Type 1 · individual
8 nearest rheumatology physician records → All 145 in Colorado → Look up another NPI →
Also registered at 1400 Jackson St
A shared address usually means a shared clinic or building; it does not show who employs whom.
- Ronya Ajeel, APN-CRNACertified Registered Nurse Anesthetist1184279044
- Akrum Al-Zubaidi, D.O.Pulmonary Disease Physician1649426222
- Rafeul Alam, MDAllergy & Immunology Physician1790730687
- Jon Allison, PACMedical Physician Assistant1609812668
- Vivianne Allsop, MDRheumatology Physician1215499603
- Mark Aloia, MDPsychiatry Physician1295842607
Verify Stuart S. Kassan in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersColorado Medical Board
Search for license 21547Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
30% fewer Medicare Part D claims than the average rheumatology physician in 2024
1,389 Medicare Part D claims for 243 beneficiaries, against an average of 1,978 among the 6,301 providers of this specialty who prescribed in Part D. Brand-name drugs were 11% of claims.
Most prescribed
- Hydroxychloroquine Sulfate317 claims
- Prednisone186 claims
- Methotrexate76 claims
- Pilocarpine Hcl56 claims
- Gabapentin43 claims
- Cevimeline Hcl42 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.
One hospital affiliation
- National Jewish HealthDenver, CO · Acute Care Hospitals
Source: CMS Doctors and Clinicians National Downloadable File (the group practices a clinician bills Medicare through); hospitals matched to CMS Hospital General Information (Care Compare) (data.cms.gov).
Stuart S. Kassan among 145 rheumatology physician records in Colorado
Stuart S. Kassan, MD is one of 145 rheumatology physician records with a practice address in Colorado. 81% of them appear in a Medicare file (Part D prescribing, MIPS, Open Payments or Medicare group billing); this one does. Its NPI, issued in 2005, is newer than 0% of them.
- NPI issued2005 · 0% of these records are older, 92% newer
- In a Medicare fileYes · 81% of these records are
- In the CMS Doctors and Clinicians fileYes · 70% of these records are
- Graduated1972 · median 2004 among the 102 with a school on file
- Record last updated2023 · 51% of these records were not updated in five years or more
Source: CMS NPPES, file of Aug 9, 2026, every record with primary taxonomy 207RR0500X and a Colorado practice address; Medicare files: CMS Part D Prescribers 2024, MIPS 2023, Open Payments 2024, Doctors and Clinicians (data.cms.gov).
Rheumatology Physician providers in Colorado
There are 145 rheumatology physician records in Colorado.
All 145 in Colorado → Every provider in Denver → Rheumatology Physician nationwide →
The 8 rheumatology physician records with the nearest ZIP codes
- Vivianne Allsop, MDDenver, CO 802061215499603
- Bjorn Anderson, MDDenver, CO 802061922521442
- Marc Cohen, M.D.Denver, CO 802061053301739
- Aryeh Fischer, M.D.Denver, CO 802061669436259
- Rebecca Gordon, M.D.Denver, CO 802061316168834
- Ivana IlicDenver, CO 802061285194555
- Liudmila Kastsianok, M.D.Denver, CO 802061659638492
- Mehrnaz Maleki Fischbach, MDDenver, CO 802061487849642
Common questions
What is Stuart S. Kassan, MD's NPI number?
Stuart S. Kassan, MD's National Provider Identifier (NPI) is 1093706475, issued on Nov 3, 2005. An NPI identifies a provider in billing; it is not a license.
Where is Stuart S. Kassan, MD located?
The NPPES record lists a practice address at 1400 Jackson St, Denver, CO, 80206. Phone: (303) 388-4461. Providers update this record themselves, so call before visiting.
How can I verify Stuart S. Kassan, MD's license?
NPPES lists Colorado license number 21547, as entered by the provider. Search the Colorado Medical Board at https://dpo.colorado.gov/Medical. The NPPES record confirms identity only; the state search shows license status, expiration and public orders.
How much does Stuart S. Kassan, MD prescribe under Medicare Part D?
In 2024, Stuart S. Kassan, MD had 1,389 Medicare Part D claims for 243 beneficiaries; the average among rheumatology physician prescribers was 1,978. Part D covers Medicare prescriptions only.
Source: CMS National Plan and Provider Enumeration System (NPPES), file of Aug 9, 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.
Figures on PlainDoctor are read from the federal files each page names (CMS NPPES, Medicare Part D, MIPS, Open Payments; the HHS-OIG exclusion list only as counts) and from Census population estimates, with the file date shown beside them. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of Aug 9, 2026.