Derek D. Mafong, M.D.
Endocrinology, Diabetes & Metabolism Physician · San Diego, CA
Derek D. Mafong, M.D. is an endocrinology, diabetes & metabolism physician with a practice address in San Diego, California, and NPI 1699781633, issued on Jul 31, 2006. Check the license (California A89536, as entered in NPPES) on the Medical Board of California; the Medicare figures below come from public CMS files.
- Name
- Derek D. Mafong
- Credential
- M.D.
- Primary taxonomy
- Endocrinology, Diabetes & Metabolism Physician 207RE0101X
- License number
- A89536 CA
Self-reported in NPPES; status is on the state search - Practice location
- 200 W Arbor Dr, San Diego, CA 92103
- Phone
- (800) 926-8273
- Enumerated
- Jul 31, 2006
- Record last updated
- Dec 2, 2021 (not updated in 5 years: call before relying on the address or phone)
- Medicare enrollment
- Enrolled (PECOS I20070719000220); accepts Medicare assignment
- Medical or professional school
- University Of California, San Francisco School Of Medicine, 2001
- Entity
- Type 1 · individual
8 nearest endocrinology, diabetes & metabolism physician records → All 1,131 in California → Look up another NPI →
Also registered at 200 W Arbor Dr
A shared address usually means a shared clinic or building; it does not show who employs whom.
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- Geraldine Abcede, RNCertified Registered Nurse Anesthetist1982384046
- Joseph Abdelmalek, M.DNephrology Physician1740485531
- Kristy AbelCertified Registered Nurse Anesthetist1962113035
- Paula Abeleda, NPFamily Nurse Practitioner1558945022
Verify Derek D. Mafong in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersMedical Board of California
Search for license A89536Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
49% fewer Medicare Part D claims than the average endocrinology, diabetes & metabolism physician in 2024
1,335 Medicare Part D claims for 337 beneficiaries, against an average of 2,630 among the 8,223 providers of this specialty who prescribed in Part D. Brand-name drugs were 37% of claims.
Most prescribed
- Levothyroxine Sodium218 claims
- Methimazole158 claims
- Ozempic117 claims
- Alendronate Sodium53 claims
- Forteo49 claims
- Nano 2nd Gen Pen Needle46 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.
Industry payments in 2024: $9.66
1 payment: food and beverage; the largest payer was Irras USA, Inc. The 5,661 providers of this specialty with any payment received $5,742.15 on average. Payments are reported by manufacturers, not by the provider, and are not a sign of wrongdoing.
Source: CMS Open Payments, program year 2024 (openpaymentsdata.cms.gov); average among providers of this specialty with at least one payment.
Bills Medicare through one group practice
- Southern California Permanente Medical GroupSan Diego, CA
Source: CMS Doctors and Clinicians National Downloadable File (the group practices a clinician bills Medicare through) (data.cms.gov).
Derek D. Mafong among 1,131 endocrinology, diabetes & metabolism physician records in California
Derek D. Mafong, M.D. is one of 1,131 endocrinology, diabetes & metabolism physician records with a practice address in California. 84% 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 5% of them.
- NPI issued2006 · 5% of these records are older, 54% newer
- In a Medicare fileYes · 84% of these records are
- In the CMS Doctors and Clinicians fileYes · 69% of these records are
- Graduated2001 · median 2003 among the 779 with a school on file
- Record last updated2021 · 57% of these records were not updated in five years or more
Source: CMS NPPES, file of Aug 9, 2026, every record with primary taxonomy 207RE0101X and a California practice address; Medicare files: CMS Part D Prescribers 2024, MIPS 2023, Open Payments 2024, Doctors and Clinicians (data.cms.gov).
Endocrinology, Diabetes & Metabolism Physician providers in California
There are 1,131 endocrinology, diabetes & metabolism physician records in California.
All 1,131 in California → Every provider in San Diego → Endocrinology, Diabetes & Metabolism Physician nationwide →
The 8 endocrinology, diabetes & metabolism physician records with the nearest ZIP codes
- Suvesh Chandiok, MDSan Diego, CA 921031235112608
- Edward Chao, DOSan Diego, CA 921031932298122
- Wolfgang Dillman, M.D.San Diego, CA 921031386675445
- Chris Guerin, M.D.San Diego, CA 921031275648875
- Nadeen Hosein, M.D.San Diego, CA 921031912051715
- Kelli Karches, M.D., MPHSan Diego, CA 921031891997631
- Kristen Kulasa, M.D.San Diego, CA 921031932324175
- Karen McCowen, M.D.San Diego, CA 921031972541274
Common questions
What is Derek D. Mafong, M.D.'s NPI number?
Derek D. Mafong, M.D.'s National Provider Identifier (NPI) is 1699781633, issued on Jul 31, 2006. An NPI identifies a provider in billing; it is not a license.
Where is Derek D. Mafong, M.D. located?
The NPPES record lists a practice address at 200 W Arbor Dr, San Diego, CA, 92103. Phone: (800) 926-8273. Providers update this record themselves, so call before visiting.
How can I verify Derek D. Mafong, M.D.'s license?
NPPES lists California license number A89536, 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 Derek D. Mafong, M.D. prescribe under Medicare Part D?
In 2024, Derek D. Mafong, M.D. had 1,335 Medicare Part D claims for 337 beneficiaries; the average among endocrinology, diabetes & metabolism physician prescribers was 2,630. 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.