Oscar Chien, M.D.
NPI 1679675904 · Geriatric Medicine (Internal Medicine) Physician · San Gabriel, CA
Enrolled with Medicare as Practitioner - Internal Medicine · source: CMS PECOS Public Provider Enrollment (2026.04.01)
Provider details
- NPI number
- 1679675904
- Entity type
- Individual
- Primary specialty
- Geriatric Medicine (Internal Medicine) PhysicianAllopathic & Osteopathic Physicians
- Credential
- M.D.
- Sex
- Male
- Sole proprietor
- Yes
- License
- A54999 (CA)
Specialties & taxonomies
Allopathic & Osteopathic Physicians
Profile Score
A profile completeness & documented-activity index — NOT a quality, outcomes, or patient-satisfaction rating.
- Registry tenure25% of score
19 yrs in NPPES registry
- Profile completeness25% of score
100% of core fields populated
- Practice footprint15% of score
1 documented practice location
- Medicare service volume (vs. specialty peers)25% of score
5,197 Medicare services, 2024 (ranked within specialty)
- Open Payments transparency10% of score
Has Open Payments disclosures (2024)
Medicare volume is ranked against active providers in the same specialty. Signals a provider has no public data for (e.g. Medicare claims) are left out of the score entirely — never counted as zero — so providers without that data are not penalized. See the full formula and weights in our .
What this provider does (Medicare)
Based on Medicare fee-for-service claims, 2024; not all care is captured.
| Service (HCPCS) | Medicare services | Typical Medicare-allowed (2024) |
|---|---|---|
| Established Patient Office Or Other Outpatient Visit With Moderate Level of Decision Making, If Using Time, 30 Minutes Or More99214 | 2,140 | $93 |
| Subsequent Hospital Care With Moderate Levelof Medical Decision Making, If Using Time, at Least 35 Minutes99232 | 1,199 | $76 |
| Subsequent Nursing Facility Care With High Level of Medical Decision Making, Per Day, If Using Time, at Least 45 Minutes99310 | 727 | $147 |
| Initial Hospital Care With Moderate Level of Medical Decision Making, If Using Time, at Least 75 Minutes99223 | 155 | $166 |
| Hospital Discharge Day Management, More Than 30 Minutes99239 | 140 | $111 |
| Physician Or Allowed Practitioner Re-Certification for Medicare-Covered Home Health Services Under a Home Health Plan of Care (patient Not Present), Including Contacts With Home Health Agency and Review of Reports of Patient Status Required By Physicians a |
What this provider prescribes (Medicare Part D)
Top drugs by Medicare Part D claim volume, 2024 · 313 distinct drugs on file.
| Drug | Part D claims (2024) | Beneficiaries |
|---|---|---|
| Atorvastatin Calcium | 1,782 | 310 |
| Losartan Potassium | 1,463 | 260 |
| Amlodipine Besylate | 1,333 | 233 |
| Pantoprazole Sodium | 1,040 | 191 |
| Empagliflozinbrand: Jardiance | 875 | 137 |
| Metoprolol Succinate | 857 | 153 |
Transparency — industry payments
Based on CMS Open Payments, 2024; not all care is captured.
$27,480 across 151 records (Open Payments 2024)
Open Payments discloses payments and transfers of value (meals, travel, consulting, research, royalties) from drug and device makers to providers. This is a transparency signal, not a verdict — such payments are legal and common, and their presence is neither an endorsement nor a criticism. Source: CMS Open Payments, program year 2024.
Practice location
Mailing address
Registry dates
- Enumerated
- 2006-09-05
- Last updated
- 2020-04-02
- Certified
- 2020-04-02
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.