John Stephen Hammes, M.D.
Nephrology Physician · San Diego, CA
John Stephen Hammes, M.D. is a nephrology physician with a practice address in San Diego, California, and NPI 1891766994, issued on Jan 28, 2006. Check the license (California G84351, as entered in NPPES) on the Medical Board of California; the Medicare figures below come from public CMS files.
- Name
- John Stephen Hammes
- Credential
- M.D.
- Primary taxonomy
- Nephrology Physician 207RN0300X
- License number
- G84351 CA
Self-reported in NPPES; status is on the state search - Practice location
- 8885 Rio San Diego Dr Ste 212, San Diego, CA 92108
- Phone
- (619) 299-2350
- Enumerated
- Jan 28, 2006
- Record last updated
- Jun 15, 2026
- Fax
- (619) 297-8379
- Medicare enrollment
- Enrolled (PECOS I20120928000492); accepts Medicare assignment
- Medical or professional school
- Uniformed Services Uhs Fe Hebert School Of Med, 1993
- Telehealth
- Offers telehealth (CMS)
- Entity
- Type 1 · individual
Also registered at 8885 Rio San Diego Dr Ste 212
A shared address usually means a shared clinic or building; it does not show who employs whom.
- Angelica Camargo- Lowthers, NPNurse Practitioner1912982539
- Jason Davis, MDNephrology Physician1295911469
- Maple Fung, M.D.Nephrology Physician1316901101
- Viet Nguyen, M.D.Nephrology Physician1184019051
- Maryam Shahamfar, MDNephrology Physician1194354944
- Yan Zhong, M.D.Nephrology Physician1467683540
Verify John Stephen Hammes in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersMedical Board of California
Search for license G84351Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
11% more Medicare Part D claims than the average nephrology physician in 2024
1,631 Medicare Part D claims for 233 beneficiaries, against an average of 1,465 among the 10,986 providers of this specialty who prescribed in Part D. Brand-name drugs were 18% of claims.
Most prescribed
- Furosemide144 claims
- Losartan Potassium88 claims
- Sevelamer Carbonate69 claims
- Atorvastatin Calcium59 claims
- Chlorthalidone50 claims
- Potassium Chloride49 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: $58.69
2 payments; by number, the most common kind was food and beverage; the largest payer was Nxstage Medical, Inc. The 8,230 providers of this specialty with any payment received $3,091.37 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 2 group practices
- Balboa Nephrology Medical Group IncSan Diego, CA
- Emergency And Acute Care Medical CorporationCoronado, CA
Source: CMS Doctors and Clinicians National Downloadable File (the group practices a clinician bills Medicare through) (data.cms.gov).
Nephrology Physician providers in California
There are 1,468 nephrology physician records in California.
Other nephrology physician records in California
- Antoine Abcar, MDLos Angeles, CA1245301159
- Basmah Abdalla, M.D.Los Angeles, CA1629394002
- Omaran Abdeen, M.D.Mission Hills, CA1700878410
- Joseph Abdelmalek, M.DSan Diego, CA1740485531
- Lama Abdelnour, MDLos Angeles, CA1477817542
- Amir Abdi Pour, MDLoma Linda, CA1912187477
- Anas Abou-Ismail, MDPalm Springs, CA1598078784
- Graham Abra, M.D.Stanford, CA1760644678
- Sreedhar Adapa, M.D.Visalia, CA1881997872
- Gbemisola Adenuga, M.D.Los Angeles, CA1952464661
Common questions
What is John Stephen Hammes, M.D.'s NPI number?
John Stephen Hammes, M.D.'s National Provider Identifier (NPI) is 1891766994, issued on Jan 28, 2006. An NPI identifies a provider in billing; it is not a license.
Where is John Stephen Hammes, M.D. located?
The NPPES record lists a practice address at 8885 Rio San Diego Dr Ste 212, San Diego, CA, 92108. Phone: (619) 299-2350. Providers update this record themselves, so call before visiting.
How can I verify John Stephen Hammes, M.D.'s license?
NPPES lists California license number G84351, 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 John Stephen Hammes, M.D. prescribe under Medicare Part D?
In 2024, John Stephen Hammes, M.D. had 1,631 Medicare Part D claims for 233 beneficiaries; the average among nephrology physician prescribers was 1,465. 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.