Dr. Vivian To, DO
- Medicare services, 2024
- 100
- Medicare patients, 2024
- 66
- Part D claims, 2024
- 672
- Hospital affiliations
- 5
- Industry payments
- $117
- Practice address
- 100 S Raymond Ave, Alhambra, CA 91801
- Practice phone
- Call (626) 570-1606
- Professional email
- Get professional email
- Personal email
- Get personal email
- Mobile number
- Get mobile number
Primary practice
Find Dr. To's professional email, personal email and mobile number
Dmand AI checks each channel through healthcare-specific waterfall enrichment. See what is on file with a free account, with practice phones, licenses and affiliations.
Dr. Vivian To is a hospitalist in Alhambra, California
Dr. To practices at Alhambra Hospital Medical Center in Alhambra, California, part of AHMC Healthcare.
Dr. To's NPI, 1043899230, was assigned on April 5, 2021. Dr. To graduated from West Virginia School of Osteopathic Medicine in 2021. Dr. To holds California license 20A21692.
- NPI
- 1043899230NPI Registry (opens in a new tab)
- Medicare PAC ID
- 3779945407
- NPI enumeration date
- April 5, 2021
- NPI status
- Active
- Accepts Medicare assignment
- Yes
- Practice phone
- (626) 570-1606
- Professional email
- Get email
- Personal email
- Get email
- Mobile number
- Get number
- Sex
- Female
- Estimated age
- 31
- Medical school graduation
- 2021
Sources: NPPES NPI Registry (CMS); Dmand AI Professional Profile Data; Dmand AI Affiliation Data; and Doctors and Clinicians National Downloadable File (CMS)
Dr. Vivian To practices at Alhambra Hospital Medical Center in Alhambra, California
Dr. To's primary practice is Alhambra Hospital Medical Center, at 100 S Raymond Ave, Alhambra, CA 91801 in Los Angeles County. The practice phone is (626) 570-1606.
- Alhambra Hospital Medical Center100 S Raymond Ave, Alhambra, CA 91801 · Los Angeles CountyPhone(626) 570-1606
Source: Dmand AI Affiliation Data
Dr. Vivian To is affiliated with 6 sites of care and 3 medical groups
Dr. To's primary practice is Alhambra Hospital Medical Center in Alhambra, California, part of AHMC Healthcare. Dr. To is also affiliated with PIH Health Good Samaritan Hospital. The medical group on file is Optum - Downtown Los Angeles. Dmand AI also links Dr. To to 3 more hospitals, 2 medical groups and 1 skilled nursing facility, each named with a free account.
Sources: Dmand AI Affiliation Data; and Dmand AI Org Hierarchy Data
Dmand AI tracks the EHR system at Dr. Vivian To's practice
Dmand AI tracks the electronic health record (EHR) system at each site where Dr. To practices, 6 sites in all. Vendor and product names are available with a free account.
| Site | EHR vendor and product |
|---|---|
| Alhambra Hospital Medical Center | Available with a free account |
| +5 more sites and 2 medical groups | Available with a free account |
Source: Dmand AI Technology Install Data
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Dr. Vivian To is one of 3,186 hospitalists in California
Hospitalist is Dr. To's primary specialty in the NPI Registry, under taxonomy code 208M00000X. Dr. To is licensed in California.
Specialties and state licenses
- Hospitalist, CaliforniaPrimary
Hospitalists near Dr. To
Counts of hospitalists with a Dmand AI profile, by place and practice. Each opens the list.
Sources: NPPES NPI Registry (CMS); Dmand AI Professional Profile Data; and Dmand AI Peer Benchmarks
Dr. Vivian To billed Medicare for 100 services in 2024
CMS data shows 100 Medicare services from Dr. To across 4 procedure codes in 2024, for 66 Medicare patients. Medicare paid $9,615 for them.
Where Dr. To's Medicare services took place, 2024
- In an office2424%
- In a facility7676%
Dr. To compared with the California median for hospitalists, 2024
- Dr. To
- California median
- Medicare services
- 100vs 43077% below
- Medicare patients
- 66vs 20167% below
- Part D claims
- 290vs 694.2 times
Medians across 2,991 hospitalists in California with Dmand AI profiles that report each measure.
Dr. To's most billed Medicare procedure codes, 2024
CMS publishes codes billed for 11 or more Medicare patients. Each label is the code family; CPT descriptions are licensed by the AMA.
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Sources: Medicare Physician & Other Practitioners - by Provider and Service (CMS), 2024 data; and Dmand AI Peer Benchmarks
Dr. Vivian To treated 66 Medicare patients in 2024, average age 78
CMS counts 66 Medicare patients who saw Dr. To in 2024. The largest group is 85 and over, with 25 patients. 75% of them have high blood pressure, and 75% have high cholesterol. 70% are also on Medicaid. Their average risk score is 2.13, where 1.00 is the Medicare average, so they are sicker than most Medicare patients.
Across all payers, Dmand AI patient panel data puts Dr. To's median patient age at 62, with 50% women.
Dr. To's Medicare patients by age, 2024
CMS leaves out age groups with fewer than 11 patients.
Dr. To's Medicare patients by sex, 2024
- Women4162%
- Men2538%
Chronic conditions among Dr. To's Medicare patients, 2024
- High blood pressure75%
- High cholesterol75%
- Arthritis47%
- Chronic kidney disease45%
- Diabetes44%
- Osteoporosis41%
- Heart failure36%
- Alzheimer's and dementia33%
Share of Medicare patients with each condition. A patient can have several.
Dr. To's patients across all payers
Dmand AI patient panel data covers Medicare, Medicaid and commercial patients.
Patient panel by age, all payers
Median age 62
Patient panel by sex, all payers
- Women50%
- Men50%
Sources: Dmand AI Patient Panel Data; and Medicare Physician & Other Practitioners - by Provider (CMS), 2024 data
Dr. Vivian To wrote 672 Medicare Part D claims in 2024
In 2024, Dr. To wrote 672 Medicare Part D claims for 254 patients. 87% of them were for generic drugs. CMS names the drug for 290 of them, across 14 drugs with 11 or more claims each, at $4,391 in total drug cost.
Dr. To's Part D claims by kind of drug, 2024
- Generic587 claims87%
- Brand-name and other85 claims13%
Dr. To's most prescribed drugs by claims, 2024
CMS names a drug when it has 11 or more claims. Share is of the claims for drugs CMS names.
Drug classes CMS tracks in Dr. To's Part D claims, 2024
- Opioids2%11 of 672 claims
- Antibiotics10%66 of 672 claims
Share of all Part D claims for each drug class CMS reports on. Classes with no claims are left out.
Sources: Medicare Part D Prescribers - by Provider and Drug (CMS), 2024 data, released May 6, 2026; and Medicare Part D Prescribers - by Provider (CMS), 2024 data
How Dr. Vivian To takes part in Medicare
Dr. To accepts Medicare assignment, so Medicare's approved amount is taken as full payment.
- Accepts Medicare assignment
- Yes
Source: Doctors and Clinicians National Downloadable File (CMS)
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Dr. Vivian To received $117 in industry payments in 2025
CMS Open Payments shows 1 general payment to Dr. To from 1 drug or device company in 2025. Food and beverage make up the largest share, 100% of the total. AstraZeneca Pharmaceuticals LP paid the most, $117.
Companies that paid Dr. To the most, 2025 to 2025
Share is of all general payments to this clinician.
Source: Open Payments (CMS), 2025 data, released July 7, 2026
Dr. Vivian To graduated from West Virginia School of Osteopathic Medicine
Dr. To graduated from West Virginia School of Osteopathic Medicine in 2021.
- Medical school
Source: Dmand AI Professional Profile Data
Sources for Dr. Vivian To's profile data
| Data on this page | Source |
|---|---|
| NPI, name, sex, specialty and licenses | NPPES NPI Registry (CMS) (opens in a new tab)Dmand AI Professional Profile Data |
| Practice locations and phone | Dmand AI Affiliation Data |
| Primary practice, affiliations and health system | Dmand AI Affiliation DataDmand AI Org Hierarchy Data |
| Medicare services and procedure codes | Medicare Physician & Other Practitioners - by Provider and Service (CMS) (opens in a new tab) |
| State medians for the same specialty | Dmand AI Peer Benchmarks |
| Medicare patients and the all-payer patient panel | Dmand AI Patient Panel DataMedicare Physician & Other Practitioners - by Provider (CMS) (opens in a new tab) |
| Part D prescribing | Medicare Part D Prescribers - by Provider and Drug (CMS) (opens in a new tab)Medicare Part D Prescribers - by Provider (CMS) (opens in a new tab) |
| MIPS scores, telehealth, assignment and procedure percentiles | Doctors and Clinicians National Downloadable File (CMS) (opens in a new tab) |
| Industry payments | Open Payments (CMS) (opens in a new tab) |
| Training, board certification and memberships | Dmand AI Professional Profile Data |
| EHR at each practice site | Dmand AI Technology Install Data |
| Similar physicians | Dmand AI Affiliation Data |
Data last refreshed October 2026Report an inaccuracyRemove my information
FAQ
Frequently asked questions about Dr. Vivian To
Spotted something out of date? Email hello@dmand.ai and we will check the record. Contact details live in the free trial.
What is Dr. Vivian To's NPI number?
Dr. Vivian To's NPI number is 1043899230. It was assigned on April 5, 2021, and it is active in the NPI Registry.
What kind of doctor is Dr. Vivian To?
Dr. Vivian To is a hospitalist in Alhambra, California. The primary specialty in the NPI Registry is Hospitalist Physician (taxonomy code 208M00000X).
Where does Dr. Vivian To practice?
Dr. To practices at 100 S Raymond Ave, Alhambra, CA 91801. Dr. To's primary practice is Alhambra Hospital Medical Center in Alhambra, California, part of AHMC Healthcare. Dmand AI also links Dr. To to 3 hospitals, 2 medical groups and 1 skilled nursing facility.
What is Dr. Vivian To's office phone number?
The practice phone on file for Dr. To is (626) 570-1606.
What is Dr. Vivian To's medical license number?
Dr. To holds California license 20A21692.
Which hospitals is Dr. Vivian To affiliated with?
Dr. To practices at Alhambra Hospital Medical Center in Alhambra, California. Dr. To is also affiliated with PIH Health Good Samaritan Hospital. Dmand AI links Dr. To to 3 more hospitals.
What medical group is Dr. Vivian To part of?
Dr. To is linked to Optum - Downtown Los Angeles. Dmand AI links Dr. To to 2 more medical groups.
Does Dr. Vivian To accept Medicare?
Yes. CMS data shows Dr. To billed Medicare for 100 services in 2024, and Dr. To accepts Medicare assignment.
How many Medicare patients does Dr. Vivian To see?
CMS counts 66 Medicare patients who saw Dr. To in 2024, with an average age of 78.
What services does Dr. Vivian To bill to Medicare?
In 2024, Dr. To's most billed Medicare services were hospital inpatient care (99233), office visit, established patient (99213) and hospital inpatient care (99239).
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Where did Dr. Vivian To go to medical school?
Dr. To graduated from West Virginia School of Osteopathic Medicine in 2021.
What drugs does Dr. Vivian To prescribe most?
In 2024 Medicare Part D data, Dr. To's most prescribed drugs by claims were Atorvastatin Calcium, Lisinopril and Metformin HCl.
Has Dr. Vivian To received payments from drug or device companies?
CMS Open Payments shows $117 in general payments to Dr. To from 1 company from 2025 to 2025. The largest total came from AstraZeneca Pharmaceuticals LP.
How long has Dr. Vivian To been practicing?
Dr. To graduated from medical school in 2021, 5 years ago.
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