Karen D. Spizer, MD
Internal Medicine Physician · Walnut Creek, CA
Karen D. Spizer, MD is an internal medicine physician with a practice address in Walnut Creek, California, and NPI 1043384365, issued on Nov 20, 2006. Check the license (California A76234, as entered in NPPES) on the Medical Board of California; the Medicare figures below come from public CMS files.
- Name
- Karen D. Spizer
- Credential
- MD
- Primary taxonomy
- Internal Medicine Physician 207R00000X
- License number
- A76234 CA
Self-reported in NPPES; status is on the state search - Practice location
- 1425 S Main St, Walnut Creek, CA 94596
- Phone
- (925) 295-4000
- Enumerated
- Nov 20, 2006
- Record last updated
- Dec 9, 2021 (not updated in 5 years: call before relying on the address or phone)
- Medicaid ID
- 00A762340 CA
- Entity
- Type 1 · individual
8 nearest internal medicine physician records → All 17,696 in California → Look up another NPI →
Also registered at 1425 S Main St
A shared address usually means a shared clinic or building; it does not show who employs whom.
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Verify Karen D. Spizer in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersMedical Board of California
Search for license A76234Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
72% fewer Medicare Part D claims than the average internal medicine physician in 2024
895 Medicare Part D claims for 143 beneficiaries, against an average of 3,176 among the 108,855 providers of this specialty who prescribed in Part D. 171 claims were for opioids.
Most prescribed
- Hydrocodone-Acetaminophen44 claims
- Gabapentin36 claims
- Furosemide34 claims
- Potassium Chloride33 claims
- Quetiapine Fumarate30 claims
- Oxycodone Hcl26 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.
Karen D. Spizer among 17,696 internal medicine physician records in California
Karen D. Spizer, MD is one of 17,696 internal medicine physician records with a practice address in California. 79% 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, 56% newer
- In a Medicare fileYes · 79% of these records are
- In the CMS Doctors and Clinicians fileNo · 63% of these records are
- Record last updated2021 · 61% of these records were not updated in five years or more
Source: CMS NPPES, file of Aug 9, 2026, every record with primary taxonomy 207R00000X and a California practice address; Medicare files: CMS Part D Prescribers 2024, MIPS 2023, Open Payments 2024, Doctors and Clinicians (data.cms.gov).
183 internal medicine physician records list a practice address in Walnut Creek
They are 183 of the 6,170 NPPES records with a practice address in Walnut Creek, and 17,696 internal medicine physician records in California.
All 17,696 in California → Every provider in Walnut Creek → Internal Medicine Physician nationwide →
The 8 internal medicine physician records with the nearest ZIP codes
- Anthony Arroyo, MDWalnut Creek, CA 945961376621458
- Sheila Bhatia, MDWalnut Creek, CA 945961225135379
- Amrita Dhaliwal, MDWalnut Creek, CA 945961164500740
- Nellia Karakozova, MDWalnut Creek, CA 945961659459154
- Joseph Long, MDWalnut Creek, CA 945961225116379
- Roxanne McDaniel, MDWalnut Creek, CA 945961457439937
- Huu Nguyen, D.O.Walnut Creek, CA 945961811966492
- Jeff Ortiz, MDWalnut Creek, CA 945961891873964
Common questions
What is Karen D. Spizer, MD's NPI number?
Karen D. Spizer, MD's National Provider Identifier (NPI) is 1043384365, issued on Nov 20, 2006. An NPI identifies a provider in billing; it is not a license.
Where is Karen D. Spizer, MD located?
The NPPES record lists a practice address at 1425 S Main St, Walnut Creek, CA, 94596. Phone: (925) 295-4000. Providers update this record themselves, so call before visiting.
How can I verify Karen D. Spizer, MD's license?
NPPES lists California license number A76234, 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 D. Spizer, MD prescribe under Medicare Part D?
In 2024, Karen D. Spizer, MD had 895 Medicare Part D claims for 143 beneficiaries; the average among internal medicine physician prescribers was 3,176. 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.