Wallen Cy Chan, M.D.
NPI 1043287857ActiveIndividual· Internal Medicine, Gastroenterology· Staten Island, NY
Internal Medicine, Gastroenterology (M.D.) in Staten Island, New York, trained at Icahn School of Medicine at Mount Sinai (class of 1989). Their prescriptions cost Medicare Part D more than their services did: $211,234 for 1,901 claims, against $94,191 paid for services in 2024. Janssen Biotech, Inc. was the largest of 6 companies reporting payments in 2025, $495.50 in all, mostly food and beverage.
Overview
| NPI | 1043287857 |
|---|---|
| Status | Active |
| Entity type | Individual |
| Credential | M.D. |
| Sole proprietor | No |
| NPI issued | Mar 1, 2006 |
| Last updated in NPPES | Apr 14, 2008 |
Specialties and licenses
| Taxonomy | Code | License | State |
|---|---|---|---|
| Internal Medicine, Gastroenterology Primary | 207RG0100X | 183203 | NY |
Exclusion screening
| List | Result | Details |
|---|---|---|
| HHS-OIG LEIE · Nov 10, 2026 | No match | Checked by NPI and by name + state |
| North Carolina Medicaid · Nov 11, 2026 | No match | — |
| New York OMIG · Nov 11, 2026 | No match | — |
| Ohio Medicaid · Nov 11, 2026 | No match | — |
| Pennsylvania Medicheck · Nov 11, 2026 | No match | — |
| Washington HCA · Nov 11, 2026 | No match | — |
Official OIG search · How matching works ·Bulk check a roster
Medicare
| Enrollment (PECOS) | Enrolled Practitioner - Gastroenterology (NY) |
|---|---|
| Accepts assignment | Yes (participating) |
Medicare services in 2024
| Medicare patients | 350 |
|---|---|
| Services billed | 655 across 32 procedure codes |
| Paid by Medicare | $94,191 |
Part D prescriptions in 2024
| Prescriptions (claims) | 1,901 · 3,259 30-day fills |
|---|---|
| Patients | 534 |
| Total drug cost | $211,234 |
| Generic share | 88% of claims |
Education and affiliations
| Medical school | Icahn School of Medicine at Mount Sinai |
|---|---|
| Graduation year | 1989 |
| Medicare specialty | Gastroenterology |
| Secondary specialties | Internal Medicine |
Medical group
- Amboy Medical Practice PCStaten Island, NY · 173 clinicians
Hospital affiliations
- Richmond University Medical CenterStaten Island, NY
- Staten Island University HospitalStaten Island, NY
Industry payments (Open Payments)
- 2025$495.50 · 25 payments from 6 companies
- 2024$511.54 · 21 payments from 10 companies
Top paying companies in 2025
| Company | Amount | Payments |
|---|---|---|
| Janssen Biotech, Inc. | $150.07 | 5 |
| Abbvie Inc. | $122.69 | 7 |
| Salix Pharmaceuticals, A Division of Bausch Health US, LLC | $62.09 | 3 |
| Gilead Sciences, Inc. | $56.30 | 3 |
| Madrigal Pharmaceuticals | $52.18 | 3 |
What the 2025 payments were for
- Food and Beverage$410.51 · 24 payments
- Education$84.99 · 1 payment
Receiving payments does not imply wrongdoing. What Open Payments covers ·original records
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All 49 gastroenterologists in Staten Island · All gastroenterologists in New York