Vivian To, DO
Hospitalist Physician · Downey, CA
Vivian To, DO is a hospitalist physician with a practice address in Downey, California, and NPI 1043899230, issued on Apr 5, 2021. Check the license (California 20A21692, as entered in NPPES) on the Medical Board of California; the Medicare figures below come from public CMS files.
- Name
- Vivian To
- Credential
- DO
- Primary taxonomy
- Hospitalist Physician 208M00000X
- License number
- 20A21692 CA
Self-reported in NPPES; status is on the state search - Practice location
- 11500 Brookshire Ave, Downey, CA 90241
- Phone
- (562) 904-5000
- Enumerated
- Apr 5, 2021
- Record last updated
- Oct 29, 2025
- Medicare enrollment
- Enrolled (PECOS I20230814000196); accepts Medicare assignment
- Medical or professional school
- West Virginia School Of Osteopathic Medicine, 2021
- Entity
- Type 1 · individual
8 nearest hospitalist physician records → All 3,099 in California → Look up another NPI →
Also registered at 11500 Brookshire Ave
A shared address usually means a shared clinic or building; it does not show who employs whom.
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- Payal Bhowmick, PHARMDPharmacotherapy Pharmacist1518783661
- Alexis BoltonFamily Nurse Practitioner1215546197
Verify Vivian To in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersMedical Board of California
Search for license 20A21692Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
29% more Medicare Part D claims than the average hospitalist physician in 2024
672 Medicare Part D claims for 254 beneficiaries, against an average of 521 among the 21,613 providers of this specialty who prescribed in Part D. 11 claims were for opioids.
Most prescribed
- Atorvastatin Calcium66 claims
- Lisinopril27 claims
- Metformin Hcl25 claims
- Levothyroxine Sodium23 claims
- Fluticasone Propionate19 claims
- Lantus Solostar18 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 2 group practices
- Apollomed Hospitalists A Medical CorporationMonterey Park, CA
- Pih Health PhysiciansDowney, CA
Source: CMS Doctors and Clinicians National Downloadable File (the group practices a clinician bills Medicare through) (data.cms.gov).
Vivian To among 3,099 hospitalist physician records in California
Vivian To, DO is one of 3,099 hospitalist physician records with a practice address in California. 90% of them appear in a Medicare file (Part D prescribing, MIPS, Open Payments or Medicare group billing); this one does. Its NPI, issued in 2021, is newer than 90% of them.
- NPI issued2021 · 90% of these records are older, 6% newer
- In a Medicare fileYes · 90% of these records are
- In the CMS Doctors and Clinicians fileYes · 81% of these records are
- Graduated2021 · median 2010 among the 2,505 with a school on file
- Record last updated2025 · 49% of these records were not updated in five years or more
Source: CMS NPPES, file of Aug 9, 2026, every record with primary taxonomy 208M00000X and a California practice address; Medicare files: CMS Part D Prescribers 2024, MIPS 2023, Open Payments 2024, Doctors and Clinicians (data.cms.gov).
Hospitalist Physician providers in California
There are 3,099 hospitalist physician records in California.
All 3,099 in California → Every provider in Downey → Hospitalist Physician nationwide →
The 8 hospitalist physician records with the nearest ZIP codes
- Kanav GuptaDowney, CA 902411457813941
- Syed Hussain, M.D.Downey, CA 902421851518872
- Han Lam, MDDowney, CA 902421770169583
- Michael QiuDowney, CA 902421427799733
- Anita Ravi, M.D.Downey, CA 902421073887972
- Matthew Salazar Adame, MDDowney, CA 902421093342487
- Olena Schwetz, M.D.Downey, CA 902421063445708
- James Tran, MDEl Segundo, CA 902451790737559
Common questions
What is Vivian To, DO's NPI number?
Vivian To, DO's National Provider Identifier (NPI) is 1043899230, issued on Apr 5, 2021. An NPI identifies a provider in billing; it is not a license.
Where is Vivian To, DO located?
The NPPES record lists a practice address at 11500 Brookshire Ave, Downey, CA, 90241. Phone: (562) 904-5000. Providers update this record themselves, so call before visiting.
How can I verify Vivian To, DO's license?
NPPES lists California license number 20A21692, 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 Vivian To, DO prescribe under Medicare Part D?
In 2024, Vivian To, DO had 672 Medicare Part D claims for 254 beneficiaries; the average among hospitalist physician prescribers was 521. 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.