Mark Mattar, MD
NPI 1841401031ActiveIndividual· Internal Medicine, Gastroenterology· Washington, DC
Internal Medicine, Gastroenterology (MD) with Medstar Medical Group II LLC, practicing in Washington, District of Columbia. Their prescriptions cost Medicare Part D more than their services did: $4,115,602 for 301 claims, against $45,595 paid for services in 2024. Janssen Biotech, Inc. was the largest of 5 companies reporting payments in 2025, $61,169 in all, mostly speaking and faculty fees. Lists Medstar Georgetown University Hospital as a hospital affiliation.
Overview
| NPI | 1841401031 |
|---|---|
| Status | Active |
| Entity type | Individual |
| Credential | MD |
| Sole proprietor | Yes |
| NPI issued | May 27, 2007 |
| Last updated in NPPES | Jan 17, 2019 |
Specialties and licenses
| Taxonomy | Code | License | State |
|---|---|---|---|
| Internal Medicine, Gastroenterology Primary | 207RG0100X | MD036652 | DC |
| Internal Medicine, Gastroenterology | 207RG0100X | 0101247425 | VA |
| Internal Medicine, Gastroenterology | 207RG0100X | A95008 | CA |
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 (DC); Practitioner - Gastroenterology (MD) |
|---|---|
| Accepts assignment | Yes (participating) |
Medicare services in 2024
| Medicare patients | 227 |
|---|---|
| Services billed | 330 across 35 procedure codes |
| Paid by Medicare | $45,595 |
Part D prescriptions in 2024
| Prescriptions (claims) | 301 · 539 30-day fills |
|---|---|
| Patients | 55 |
| Total drug cost | $4,115,602 |
| Generic share | 38% of claims |
Education and affiliations
| Graduation year | 2004 |
|---|---|
| Medicare specialty | Gastroenterology |
| Secondary specialties | Internal Medicine |
| Telehealth | Offers telehealth |
Medical group
- Medstar Medical Group II LLCWashington, DC · 3,767 clinicians
Hospital affiliation
- Medstar Georgetown University HospitalWashington, DC
Industry payments (Open Payments)
- 2025$61,169 · 50 payments from 5 companies
- 2024$62,360 · 68 payments from 8 companies
Top paying companies in 2025
| Company | Amount | Payments |
|---|---|---|
| Janssen Biotech, Inc. | $40,456 | 37 |
| Abbvie Inc. | $17,944 | 9 |
| Celltrion USA Inc. | $2,590 | 2 |
| Genzyme Corporation | $146.90 | 1 |
| Janssen Scientific Affairs, LLC | $32.22 | 1 |
What the 2025 payments were for
- Compensation for services other than consulting, including serving as faculty or as a speaker at a venue other than a continuing education program$54,712 · 19 payments
- Travel and Lodging$2,422 · 10 payments
- Consulting Fee$1,480 · 1 payment
- Food and Beverage$1,446 · 19 payments
- Honoraria$1,110 · 1 payment
Receiving payments does not imply wrongdoing. What Open Payments covers ·original records
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