Karen Simon, M.D.
Gastroenterology Physician · Oxnard, CA
Karen Simon, M.D. is a gastroenterology physician with a practice address in Oxnard, California, and NPI 1548384167, issued on Mar 19, 2007. Check the license (California A81831, as entered in NPPES) on the Medical Board of California; the Medicare figures below come from public CMS files.
- Name
- Karen Simon
- Credential
- M.D.
- Primary taxonomy
- Gastroenterology Physician 207RG0100X
- License number
- A81831 CA
Self-reported in NPPES; status is on the state search - Practice location
- 2241 Wankel Way, Oxnard, CA 93030
- Phone
- (805) 983-0521
- Enumerated
- Mar 19, 2007
- Record last updated
- Dec 9, 2015 (not updated in 11 years: call before relying on the address or phone)
- Fax
- (805) 485-1484
- Medicare enrollment
- Enrolled (PECOS I20050124000914); accepts Medicare assignment
- Medical or professional school
- Northwestern University Feinberg Medical School, 2001
- Telehealth
- Offers telehealth (CMS)
- Entity
- Type 1 · individual
8 nearest gastroenterology physician records → All 2,140 in California → Look up another NPI →
Also registered at 2241 Wankel Way
A shared address usually means a shared clinic or building; it does not show who employs whom.
- John Billesdon, M.D.Gastroenterology Physician1184648933
- Richard Brand, MDInternal Medicine Physician1770527608
- Khamaj Dave, MDCardiovascular Disease Physician1275594657
- Esam Obed, MDCardiovascular Disease Physician1568422350
- Richard Rothschild, MDCardiovascular Disease Physician1700847126
- Paul Sanchez, M.D.Gastroenterology Physician1336156207
Verify Karen Simon in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersMedical Board of California
Search for license A81831Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
10% fewer Medicare Part D claims than the average gastroenterology physician in 2024
732 Medicare Part D claims for 196 beneficiaries, against an average of 811 among the 16,445 providers of this specialty who prescribed in Part D. Brand-name drugs were 19% of claims.
Most prescribed
- Pantoprazole Sodium95 claims
- Omeprazole83 claims
- Mesalamine39 claims
- Dicyclomine Hcl38 claims
- Diphenoxylate-Atropine36 claims
- Sucralfate34 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 practice group's MIPS final score for 2023 (Medicare payment program): 84 of 100
The Merit-based Incentive Payment System score is reported for the practice group, not for one clinician alone. 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, group reporting; category weights for 2023 (qpp.cms.gov).
Industry payments in 2024: $2,143.71
92 payments; by number, the most common kind was food and beverage; the largest payer was Abbvie Inc. The 13,350 providers of this specialty with any payment received $5,015.95 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
- Genesis Healthcare Partners PCOxnard, CA
Source: CMS Doctors and Clinicians National Downloadable File (the group practices a clinician bills Medicare through) (data.cms.gov).
Karen Simon among 2,140 gastroenterology physician records in California
Karen Simon, M.D. is one of 2,140 gastroenterology physician records with a practice address in California. 83% of them appear in a Medicare file (Part D prescribing, MIPS, Open Payments or Medicare group billing); this one does. Its NPI, issued in 2007, is newer than 52% of them.
- NPI issued2007 · 52% of these records are older, 37% newer
- In a Medicare fileYes · 83% of these records are
- In the CMS Doctors and Clinicians fileYes · 72% of these records are
- Graduated2001 · median 2002 among the 1,538 with a school on file
- Record last updated2015 · 60% of these records were not updated in five years or more
Source: CMS NPPES, file of Aug 9, 2026, every record with primary taxonomy 207RG0100X and a California practice address; Medicare files: CMS Part D Prescribers 2024, MIPS 2023, Open Payments 2024, Doctors and Clinicians (data.cms.gov).
Gastroenterology Physician providers in California
There are 2,140 gastroenterology physician records in California.
All 2,140 in California → Every provider in Oxnard → Gastroenterology Physician nationwide →
The 8 gastroenterology physician records with the nearest ZIP codes
- Constante Abaya, MDOxnard, CA 930301003918459
- John Billesdon, M.D.Oxnard, CA 930301184648933
- Cecilio Cabansag, M.D.Oxnard, CA 930301417144809
- Mohammad Khan, M.D.Oxnard, CA 930301295778215
- Justin Marasigan, DOOxnard, CA 930301174714067
- Donald Miller, MDOxnard, CA 930301023056850
- Paul Sanchez, M.D.Oxnard, CA 930301336156207
- Keval Shah, D.O.Oxnard, CA 930301093035917
Common questions
What is Karen Simon, M.D.'s NPI number?
Karen Simon, M.D.'s National Provider Identifier (NPI) is 1548384167, issued on Mar 19, 2007. An NPI identifies a provider in billing; it is not a license.
Where is Karen Simon, M.D. located?
The NPPES record lists a practice address at 2241 Wankel Way, Oxnard, CA, 93030. Phone: (805) 983-0521. Providers update this record themselves, so call before visiting.
How can I verify Karen Simon, M.D.'s license?
NPPES lists California license number A81831, 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 Karen Simon, M.D. prescribe under Medicare Part D?
In 2024, Karen Simon, M.D. had 732 Medicare Part D claims for 196 beneficiaries; the average among gastroenterology physician prescribers was 811. Part D covers Medicare prescriptions only.
What is Karen Simon, M.D.'s MIPS final score?
The 2023 MIPS final score is 84 of 100, reported for the practice group. The average among 454,083 clinicians with a measured score was 83.5.
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.