Michael Drew Duffin, M.D.
Rheumatology Physician · Torrance, CA
Michael Drew Duffin, M.D. is a rheumatology physician with a practice address in Torrance, California, and NPI 1578587309, issued on Jul 26, 2006. Check the license (California G063443, as entered in NPPES) on the Medical Board of California; the Medicare figures below come from public CMS files.
- Name
- Michael Drew Duffin
- Credential
- M.D.
- Primary taxonomy
- Rheumatology Physician 207RR0500X
- License number
- G063443 CA
Self-reported in NPPES; status is on the state search - Practice location
- 3565 Del Amo Blvd, Torrance, CA 90503
- Phone
- (310) 214-0811
- Enumerated
- Jul 26, 2006
- Record last updated
- Nov 5, 2012 (not updated in 14 years: call before relying on the address or phone)
- Fax
- (310) 793-4679
- Medicare enrollment
- Enrolled (PECOS I20190328002997); accepts Medicare assignment
- Entity
- Type 1 · individual
8 nearest rheumatology physician records → All 926 in California → Look up another NPI →
Also registered at 3565 Del Amo Blvd
A shared address usually means a shared clinic or building; it does not show who employs whom.
- Kyung Ahn, RPHPharmacist1982179701
- Shefalee Amin, MDInternal Medicine Physician1164724514
- Sheila Arzani, M.D.Pediatrics Physician1669564621
- Morteza Azimian, M.D.Rheumatology Physician1295940229
- Anita Bhagavath, M.DPulmonary Disease Physician1124394135
- Jeramie Bhatia, PA-CPhysician Assistant1255469334
Verify Michael Drew Duffin in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersMedical Board of California
Search for license G063443Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
2.4 times the Medicare Part D claims of the average rheumatology physician in 2024
4,666 Medicare Part D claims for 488 beneficiaries, against an average of 1,978 among the 6,301 providers of this specialty who prescribed in Part D. Brand-name drugs were 5% of claims. 1,073 claims were for opioids.
Most prescribed
- Hydrocodone-Acetaminophen622 claims
- Prednisone479 claims
- Methotrexate457 claims
- Tramadol Hcl317 claims
- Hydroxychloroquine Sulfate297 claims
- Leflunomide240 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.
Bills Medicare through one group practice
- Sky Lakes Medical Center IncKlamath Falls, OR
Source: CMS Doctors and Clinicians National Downloadable File (the group practices a clinician bills Medicare through) (data.cms.gov).
Michael Drew Duffin among 926 rheumatology physician records in California
Michael Drew Duffin, M.D. is one of 926 rheumatology physician records with a practice address in California. 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 2006, is newer than 6% of them.
- NPI issued2006 · 6% of these records are older, 55% newer
- In a Medicare fileYes · 81% of these records are
- In the CMS Doctors and Clinicians fileYes · 69% of these records are
- Graduated1986 · median 2003 among the 641 with a school on file
- Record last updated2012 · 62% 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 California practice address; Medicare files: CMS Part D Prescribers 2024, MIPS 2023, Open Payments 2024, Doctors and Clinicians (data.cms.gov).
Rheumatology Physician providers in California
There are 926 rheumatology physician records in California.
All 926 in California → Every provider in Torrance → Rheumatology Physician nationwide →
The 8 rheumatology physician records with the nearest ZIP codes
- Morteza Azimian, M.D.Torrance, CA 905031295940229
- Steve Aziz, M.D.Torrance, CA 905031982966271
- David Oh, M.D.Torrance, CA 905031366549255
- Viet Bui, MD, PHDTorrance, CA 905021396092227
- William Chin, M.D.Torrance, CA 905021790995769
- Dilrukshie Cooray, M.D.Torrance, CA 905021366548646
- George Karpouzas, M.D.Torrance, CA 905021154384303
- Michael Liebling, M.D.Torrance, CA 905021386691376
Common questions
What is Michael Drew Duffin, M.D.'s NPI number?
Michael Drew Duffin, M.D.'s National Provider Identifier (NPI) is 1578587309, issued on Jul 26, 2006. An NPI identifies a provider in billing; it is not a license.
Where is Michael Drew Duffin, M.D. located?
The NPPES record lists a practice address at 3565 Del Amo Blvd, Torrance, CA, 90503. Phone: (310) 214-0811. Providers update this record themselves, so call before visiting.
How can I verify Michael Drew Duffin, M.D.'s license?
NPPES lists California license number G063443, as entered by the provider. Search the Medical Board of California at https://www.mbc.ca.gov/License-Verification/default.aspx. The NPPES record confirms identity only; the state search shows license status, expiration and public orders.
How much does Michael Drew Duffin, M.D. prescribe under Medicare Part D?
In 2024, Michael Drew Duffin, M.D. had 4,666 Medicare Part D claims for 488 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.