Andrew Chang, MD
NPI 1477632131 · Internal Medicine Physician · Walnut Creek, CA
Enrolled with Medicare as Practitioner - Internal Medicine · source: CMS PECOS Public Provider Enrollment (2026.04.01)
Andrew Chang, MD is a Internal Medicine Physician provider in Walnut Creek, CA (NPI 1477632131).
Provider details
- NPI number
- 1477632131
- Entity type
- Individual
- Primary specialty
- Internal Medicine PhysicianAllopathic & Osteopathic Physicians
- Credential
- MD
- Sex
- Male
- Sole proprietor
- No
- License
- A76647 (CA)
Specialties & taxonomies
Allopathic & Osteopathic Physicians
Profile Score
A profile completeness & documented-activity index — NOT a quality, outcomes, or patient-satisfaction rating.
- Registry tenure33% of score
19 yrs in NPPES registry
- Profile completeness33% of score
100% of core fields populated
- Practice footprint20% of score
1 documented practice location
- Open Payments transparency13% of score
Has Open Payments disclosures (2024)
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 methodology.
What this provider prescribes (Medicare Part D)
Top drugs by Medicare Part D claim volume, 2024 · 121 distinct drugs on file.
| Drug | Part D claims (2024) | Beneficiaries |
|---|---|---|
| Atorvastatin Calcium | 1,137 | 415 |
| Lisinopril | 539 | 199 |
| Amlodipine Besylate | 518 | 210 |
| Hydrochlorothiazide | 397 | 135 |
| Losartan Potassium | 367 | 135 |
| Levothyroxine Sodium | 302 | 114 |
| Hydrocodone/Acetaminophen |
Transparency — industry payments
Based on CMS Open Payments, 2024; not all care is captured.
$24 across 1 record (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
- 2006-11-03
- Last updated
- 2021-12-09
Frequently asked questions
- What is Andrew Chang's NPI number?
- Andrew Chang's National Provider Identifier (NPI) is 1477632131, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is Andrew Chang's specialty?
- Andrew Chang is listed in the NPPES registry with a primary specialty of Internal Medicine Physician (Allopathic & Osteopathic Physicians).
- Where is Andrew Chang located?
- Andrew Chang's practice location on file with NPPES is 1425 S Main St, Walnut Creek, CA 94596-5318.
- What is Andrew Chang's phone number?
- The practice phone number listed in the NPPES registry for Andrew Chang is (925) 295-4000.
- Does Andrew Chang accept Medicare?
- Andrew Chang is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is Andrew Chang's NPI active?
- Yes — Andrew Chang's NPI (1477632131) is active in the NPPES registry as of the last update on 2021-12-09.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.