Mark C. Johnson, MD
NPI 1013923127ActiveIndividual· Internal Medicine· Mason City, IA
Internal Medicine (MD) in Mason City, Iowa, trained at University of Iowa, Rj & L Carver College of Medicine (class of 1977). Their prescriptions cost Medicare Part D more than their services did: $5,055,873 for 10,023 claims, against $106,099 paid for services in 2024. Novo Nordisk Inc was the largest of 7 companies reporting payments in 2025, $28,199 in all, mostly speaking and faculty fees.
Overview
| NPI | 1013923127 |
|---|---|
| Status | Active |
| Entity type | Individual |
| Credential | MD |
| Sole proprietor | No |
| NPI issued | Jul 31, 2006 |
| Last updated in NPPES | Jul 8, 2025 |
| Certified by provider | Jul 8, 2025 |
Specialties and licenses
| Taxonomy | Code | License | State |
|---|---|---|---|
| Internal Medicine Primary | 207R00000X | 21527 | IA |
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 - Endocrinology (IA) |
|---|---|
| Accepts assignment | Yes (participating) |
Medicare services in 2024
| Medicare patients | 1,561 |
|---|---|
| Services billed | 3,877 across 12 procedure codes |
| Paid by Medicare | $106,099 |
Part D prescriptions in 2024
| Prescriptions (claims) | 10,023 · 16,773 30-day fills |
|---|---|
| Patients | 716 |
| Total drug cost | $5,055,873 |
| Generic share | 25% of claims |
Education and affiliations
| Medical school | University of Iowa, Rj & L Carver College of Medicine |
|---|---|
| Graduation year | 1977 |
| Medicare specialty | Endocrinology |
| Secondary specialties | Internal Medicine |
Medical group
- North Iowa Mercy ClinicsMason City, IA · 302 clinicians
Hospital affiliations
- Floyd County Medical CenterCharles City, IA
- Hancock County Health SystemBritt, IA
- Kossuth Regional Health CenterAlgona, IA
- Mercyone North Iowa Medical CenterMason City, IA
Industry payments (Open Payments)
- 2025$28,199 · 35 payments from 7 companies
- 2024$16,974 · 47 payments from 10 companies
Top paying companies in 2025
| Company | Amount | Payments |
|---|---|---|
| Novo Nordisk Inc | $24,287 | 23 |
| Boehringer Ingelheim Pharmaceuticals, Inc. | $2,775 | 3 |
| Lilly USA, LLC | $984.11 | 2 |
| Abbott Laboratories | $99.15 | 4 |
| Dexcom, Inc. | $19.68 | 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$25,343 · 11 payments
- Travel and Lodging$1,893 · 9 payments
- Food and Beverage$962.14 · 15 payments
Receiving payments does not imply wrongdoing. What Open Payments covers ·original records
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