Joel Topf, MD
Nephrology · Roseville, MINPI 1972505519
Payments from drug & device makers
What this record shows
This record is dominated by consulting fees: $71,041 of the $78,851 with a category attached, or 90.1%. AstraZeneca accounts for 62.7% of it on its own, with 12 other manufacturers making up the rest. Reporting peaked in 2021 at $30,161 and has fallen 72.6% since, to $8,265 in 2025. Among nephrology clinicians in MI with any reported payments, this total sits in the top 5% — high for the specialty, which is a reason to read the composition above rather than the number alone.
Across 65 payments — averaging $1213.10 each. Meals, travel, consulting and speaking fees, gifts and royalties reported by drug and device makers.
- AstraZeneca$49K
- Novartis$8K
- Bayer$8K
- Vifor Pharma, Inc.$5K
- Calliditas Therapeutics US Inc.$3K
- GSK$3K
- plus $2K from 7 others
Across 300 payments — averaging $3315.02 each. Payments tied to a research study. These frequently flow through the physician to a hospital or research institution rather than to the physician personally.
- CSL Behring$291K
- Akebia Therapeutics Inc$275K
- Otsuka Pharmaceutical Development & Commercialization, Inc.$242K
- Vertex$114K
- Merck$72K
What the payments were for
- Consulting fees$71,04190%
- Speaking & faculty fees$4,0995%
- Travel & lodging$1,8952%
- Food & beverage$1,7982%
- Education$190%
General payments by program year
Who reported the general payments
Companies are grouped under their corporate parent — a single manufacturer often files under several CMS reporting entities. Research and ownership payments are counted separately and are not in this table.
| Company | Payments | Total |
|---|---|---|
| AstraZeneca | 30 | $49,414 |
| Novartis | 4 | $8,215 |
| Bayer | 9 | $7,951 |
| Vifor Pharma, Inc. | 6 | $4,708 |
| Calliditas Therapeutics US Inc. | 3 | $3,269 |
| GSK | 2 | $2,925 |
| Novo Nordisk | 2 | $1,131 |
| Travere Therapeutics, Inc. | 3 | $832 |
| Fresenius USA Marketing, Inc. | 1 | $249 |
| Vertex | 1 | $94 |
| Boehringer Ingelheim | 2 | $42 |
| Johnson & Johnson | 1 | $11 |
| Amgen | 1 | $11 |
What the payments were tied to
Products named in the reported payments. Only payments of $100 or more are attributed here — the typical reported payment nationally is a meal worth about $16, and listing those product-by-product would be noise.
How this compares
$78,851 in reported general payments places this provider in the 95th percentile of 325 nephrology providers in Michigan.
Medicare billing
What this is not: this is the amount Original Medicare Part B allowed for services this provider billed in 2024. It is not their income. It excludes Medicare Advantage — now more than half of all Medicare enrollment — along with Medicaid and all commercial insurance, and it is gross practice revenue before staff, rent, supplies and malpractice premiums. CMS also suppresses any figure covering ten or fewer patients, so low-volume providers appear smaller than they are.
Most prescribed under Part D
| Drug | Claims | Cost to plans & patients |
|---|---|---|
| JardianceEmpagliflozin | 91 | $92,889 |
| FarxigaDapagliflozin Propanediol | 111 | $90,249 |
| KerendiaFinerenone | 21 | $26,843 |
| OzempicSemaglutide | 25 | $24,679 |
| JanuviaSitagliptin Phosphate | 18 | $9,698 |
| EliquisApixaban | 11 | $6,484 |
| Sevelamer Carbonate | 26 | $5,806 |
| Nifedipine ErNifedipine | 55 | $3,070 |
| Telmisartan | 94 | $2,878 |
| Chlorthalidone | 111 | $1,963 |
| Torsemide | 64 | $1,694 |
| Losartan Potassium | 78 | $820 |
| Carvedilol | 46 | $795 |
| Spironolactone | 80 | $767 |
| Olmesartan Medoxomil | 15 | $687 |
Paid to pharmacies, not to this prescriber.
Companies that both paid and supply prescribed drugs
These companies both reported payments to this provider and make drugs the provider prescribed under Medicare Part D in 2024. For most specialties this overlap is expected — a cardiologist who is paid by a cardiology drugmaker also treats heart disease. It is shown so the reader can see it, not because it implies anything on its own.
| Company | Paid to this provider | Part D cost of their drugs |
|---|---|---|
| Boehringer IngelheimJardiance | $42 | $92,88991 claims |
| AstraZenecaFarxiga | $49,414 | $90,249111 claims |
| BayerKerendia | $7,951 | $26,84321 claims |
| Novo NordiskOzempic | $1,131 | $24,67925 claims |
Reading this fairly. The Part D column is what drug plans and patients paid pharmacies — this provider received none of it, and it reflects how many patients they treat and what those drugs cost. Against peers, this provider's reported payments sit in the 95th percentile of 325 nephrology providers in Michigan.
Other nephrology in Roseville
- Alexander YevzlinAnn Arbor$1.1M
- Muwaffaq SalamehBay City$164K
- Laura MarianiAnn Arbor$150K
- Crystal Gardner-MartinLivonia$140K
- Katherine KwonSaint Joseph$111K
- Anatole BesarabDetroit$102K
- Richard CrossSaint Clair Shores$96K
- Kausik UmanathDetroit$85K
- Matthias KretzlerAnn Arbor$70K
- Claudia ZacharekSaginaw$69K
Where these figures come from
- Payments: CMS Open Payments, program years 2019–2025 (publication P06302026_06032026).
- Billing: Medicare Physician & Other Practitioners, data year 2024. Original Medicare Part B only.
- Identity: NPPES NPI Registry, July 2026.