William Weiming Chang, D.O.
NPI 1417902149ActiveIndividual· Internal Medicine, Pulmonary Disease· San Juan Capistrano, CA
Internal Medicine, Pulmonary Disease (D.O.) in San Juan Capistrano, California, trained at Michigan State University College of Osteopathic Medicine (class of 2000). Their prescriptions cost Medicare Part D more than their services did: $2,460,975 for 5,085 claims, against $437,594 paid for services in 2024. Glaxosmithkline, LLC. was the largest of 24 companies reporting payments in 2025, $2,777 in all, mostly food and beverage.
Overview
| NPI | 1417902149 |
|---|---|
| Status | Active |
| Entity type | Individual |
| Credential | D.O. |
| Sole proprietor | No |
| NPI issued | May 23, 2006 |
| Last updated in NPPES | Apr 17, 2013 |
Specialties and licenses
| Taxonomy | Code | License | State |
|---|---|---|---|
| Internal Medicine, Pulmonary Disease Primary | 207RP1001X | 20A7942 | CA |
| Specialist | 174400000X | 20A7942 | CA |
| Internal Medicine, Critical Care Medicine | 207RC0200X | 20A7942 | CA |
Exclusion screening
| List | Result | Details |
|---|---|---|
| HHS-OIG LEIE · Oct 9, 2026 | No match | Checked by NPI and by name + state |
| North Carolina Medicaid · Nov 4, 2026 | No match | — |
| New York OMIG · Nov 4, 2026 | No match | — |
| Ohio Medicaid · Nov 4, 2026 | No match | — |
| Pennsylvania Medicheck · Nov 4, 2026 | No match | — |
| Washington HCA · Nov 4, 2026 | No match | — |
Official OIG search · How matching works ·Bulk check a roster
Medicare
| Enrollment (PECOS) | Enrolled Practitioner - Pulmonary Disease (CA) |
|---|---|
| Accepts assignment | Yes (participating) |
Medicare services in 2024
| Medicare patients | 628 |
|---|---|
| Services billed | 5,984 across 79 procedure codes |
| Paid by Medicare | $437,594 |
Part D prescriptions in 2024
| Prescriptions (claims) | 5,085 · 8,316 30-day fills |
|---|---|
| Patients | 748 |
| Total drug cost | $2,460,975 |
| Generic share | 63% of claims |
Education and affiliations
| Medical school | Michigan State University College of Osteopathic Medicine |
|---|---|
| Graduation year | 2000 |
| Medicare specialty | Pulmonary Disease |
| Secondary specialties | Critical Care (Intensivists), Internal Medicine |
| Telehealth | Offers telehealth |
Medical group
- Paloma Medical Group IncSan Juan Capistrano, CA · 19 clinicians
Hospital affiliations
- Hoag Memorial Hospital PresbyterianNewport Beach, CA
- Memorialcare Saddleback Medical CenterLaguna Hills, CA
- Providence Mission HospitalMission Viejo, CA
- Providence St. Jude Medical CenterFullerton, CA
Other facilities
- Salus Home HealthHome health agency · Irvine, CA
Industry payments (Open Payments)
- 2025$2,777 · 162 payments from 24 companies
- 2024$2,040 · 111 payments from 20 companies
Top paying companies in 2025
| Company | Amount | Payments |
|---|---|---|
| Glaxosmithkline, LLC. | $518.16 | 40 |
| Astrazeneca Pharmaceuticals LP | $370.00 | 31 |
| Avadel Cns Pharmaceuticals, LLC | $324.85 | 22 |
| Verona Pharma, Inc. | $261.55 | 12 |
| Insmed, Inc. | $180.20 | 15 |
What the 2025 payments were for
- Food and Beverage$2,668 · 159 payments
- Education$108.60 · 3 payments
Receiving payments does not imply wrongdoing. What Open Payments covers ·original records
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All Internal Medicine, Pulmonary Disease providers in California →