Kenneth William Mahaffey, MD
NPI 1659455707ActiveIndividual· Internal Medicine, Cardiovascular Disease· Stanford, CA
Internal Medicine, Cardiovascular Disease (MD) in Stanford, California, trained at University of Washington School of Medicine (class of 1989). Their prescriptions cost Medicare Part D more than their services did: $39,617 for 233 claims, against $16,078 paid for services in 2024. E.R. Squibb & Sons, L.L.C. was the largest of 5 companies reporting payments in 2025, $60,575 in all, mostly consulting fees.
Overview
| NPI | 1659455707 |
|---|---|
| Status | Active |
| Entity type | Individual |
| Credential | MD |
| Sole proprietor | No |
| NPI issued | Oct 25, 2006 |
| Last updated in NPPES | Apr 23, 2024 |
| Certified by provider | Apr 23, 2024 |
Specialties and licenses
| Taxonomy | Code | License | State |
|---|---|---|---|
| Internal Medicine, Cardiovascular Disease Primary | 207RC0000X | G129600 | CA |
| Internal Medicine, Cardiovascular Disease | 207RC0000X | 96-00991 | NC |
Exclusion screening
| List | Result | Details |
|---|---|---|
| HHS-OIG LEIE · Oct 9, 2026 | No match | Checked by NPI and by name + state |
| North Carolina Medicaid · Nov 10, 2026 | No match | — |
| New York OMIG · Nov 10, 2026 | No match | — |
| Ohio Medicaid · Nov 10, 2026 | No match | — |
| Pennsylvania Medicheck · Nov 10, 2026 | No match | — |
| Washington HCA · Nov 10, 2026 | No match | — |
Official OIG search · How matching works ·Bulk check a roster
Medicare
| Enrollment (PECOS) | Enrolled Practitioner - Cardiovascular Disease (Cardiology) (CA) |
|---|---|
| Accepts assignment | Yes (participating) |
Medicare services in 2024
| Medicare patients | 845 |
|---|---|
| Services billed | 966 across 14 procedure codes |
| Paid by Medicare | $16,078 |
Part D prescriptions in 2024
| Prescriptions (claims) | 233 · 586 30-day fills |
|---|---|
| Patients | 29 |
| Total drug cost | $39,617 |
| Generic share | 81% of claims |
Education and affiliations
| Medical school | University of Washington School of Medicine |
|---|---|
| Graduation year | 1989 |
| Medicare specialty | Cardiovascular Disease (Cardiology) |
| Telehealth | Offers telehealth |
Medical group
- Stanford Health CareStanford, CA · 3,122 clinicians
Hospital affiliations
- El Camino HealthMountain View, CA
- Peninsula Medical CenterBurlingame, CA
- Santa Clara Valley Medical CenterSan Jose, CA
- Sequoia HospitalRedwood City, CA
- Stanford Health CareStanford, CA
Industry payments (Open Payments)
- 2025$60,575 · 25 payments from 5 companies
- 2024$76,674 · 51 payments from 5 companies
Top paying companies in 2025
| Company | Amount | Payments |
|---|---|---|
| E.R. Squibb & Sons, L.L.C. | $33,363 | 11 |
| Eli Lilly and Company | $18,400 | 4 |
| Modernatx, Inc. | $5,000 | 4 |
| Csl Behring | $3,168 | 1 |
| Janssen Research & Development, LLC | $644.02 | 5 |
What the 2025 payments were for
- Consulting Fee$59,931 · 20 payments
- Travel and Lodging$388.57 · 1 payment
- Food and Beverage$255.45 · 4 payments
Receiving payments does not imply wrongdoing. What Open Payments covers ·original records
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