Nathan E. Riddell, M.D.
NPI 1245670983ActiveIndividual· Internal Medicine, Cardiovascular Disease· Worcester, MA
Internal Medicine, Cardiovascular Disease (M.D.) with Lgh Merrimack Valley Cardiology Associates, LLC and 1 other group, practicing in Worcester, Massachusetts. In 2024 Medicare paid $147,495 for 1,464 patients, and Part D covered 1,331 of their prescriptions, 88% of them generic. Amgen Inc. was the largest of 11 companies reporting payments in 2025, $427.83 in all, mostly food and beverage. Lists Lowell General Hospital and 1 other hospital as hospital affiliations.
Overview
| NPI | 1245670983 |
|---|---|
| Status | Active |
| Entity type | Individual |
| Credential | M.D. |
| Sole proprietor | No |
| NPI issued | Jun 26, 2013 |
| Last updated in NPPES | Dec 8, 2025 |
| Certified by provider | Dec 8, 2025 |
Specialties and licenses
| Taxonomy | Code | License | State |
|---|---|---|---|
| Internal Medicine, Cardiovascular Disease Primary | 207RC0000X | 273386 | MA |
| Internal Medicine | 207R00000X | 256554 | MA |
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 - Internal Medicine (MA) |
|---|---|
| Accepts assignment | Yes (participating) |
Medicare services in 2024
| Medicare patients | 1,464 |
|---|---|
| Services billed | 2,418 across 87 procedure codes |
| Paid by Medicare | $147,495 |
Part D prescriptions in 2024
| Prescriptions (claims) | 1,331 · 3,466 30-day fills |
|---|---|
| Patients | 235 |
| Total drug cost | $189,579 |
| Generic share | 88% of claims |
Education and affiliations
| Graduation year | 2013 |
|---|---|
| Medicare specialty | Internal Medicine |
| Secondary specialties | Cardiovascular Disease (Cardiology) |
Medical groups
- Lgh Merrimack Valley Cardiology Associates, LLCNorth Chelmsford, MA · 22 clinicians
- Tvcg Ste PLLCLowell, MA · 7 clinicians
Hospital affiliations
- Lowell General HospitalLowell, MA
- Tufts Medical CenterBoston, MA
Industry payments (Open Payments)
- 2025$427.83 · 17 payments from 11 companies
- 2024$1,562 · 26 payments from 9 companies
Top paying companies in 2025
| Company | Amount | Payments |
|---|---|---|
| Amgen Inc. | $69.24 | 3 |
| Alnylam Pharmaceuticals Inc. | $67.77 | 3 |
| Bard Peripheral Vascular, Inc. | $62.77 | 2 |
| Boston Scientific Corporation | $55.29 | 1 |
| Novartis Pharmaceuticals Corporation | $45.39 | 2 |
What the 2025 payments were for
- Food and Beverage$427.83 · 17 payments
Receiving payments does not imply wrongdoing. What Open Payments covers ·original records
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