Dietmar J. Grentz, MD
Family Medicine Physician · Portage, MI
Dietmar J. Grentz, MD is a family medicine physician with a practice address in Portage, Michigan, and NPI 1346269586, issued on Jul 19, 2006. Check the license (Michigan 4301069296, as entered in NPPES) on the Michigan Board of Medicine (LARA); the Medicare figures below come from public CMS files.
- Name
- Dietmar J. Grentz
- Credential
- MD
- Primary taxonomy
- Family Medicine Physician 207Q00000X
- License numbers
- 4301069296 MI
036069689 IL
39564 MN
Self-reported in NPPES; status is on the state search - Practice location
- 2725 Airview Blvd, Portage, MI 49002
- Phone
- (269) 349-8386
- Enumerated
- Jul 19, 2006
- Record last updated
- Jul 22, 2016 (not updated in 10 years: call before relying on the address or phone)
- Fax
- (269) 349-8397
- Entity
- Type 1 · individual
8 nearest family medicine physician records → All 6,013 in Michigan → Look up another NPI →
Also registered at 2725 Airview Blvd
A shared address usually means a shared clinic or building; it does not show who employs whom.
- Diaa Aldin Elfaki, M.D.Internal Medicine Physician1528346053
- Terry Lewis, NP-CFamily Nurse Practitioner1174976773
Verify Dietmar J. Grentz in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersMichigan Board of Medicine (LARA)
Search for license 4301069296Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
2.3 times the Medicare Part D claims of the average family medicine physician in 2024
8,159 Medicare Part D claims for 128 beneficiaries, against an average of 3,544 among the 117,163 providers of this specialty who prescribed in Part D. Brand-name drugs were 15% of claims. 181 claims were for opioids.
Most prescribed
- Atorvastatin Calcium586 claims
- Metoprolol Succinate365 claims
- Amlodipine Besylate331 claims
- Lisinopril302 claims
- Clopidogrel243 claims
- Furosemide220 claims
Source: CMS Medicare Part D Prescribers by Provider and Drug, 2024 (data.cms.gov). Part D covers prescriptions for Medicare patients only; drugs with fewer than 11 claims are not published.
Dietmar J. Grentz among 6,013 family medicine physician records in Michigan
Dietmar J. Grentz, MD is one of 6,013 family medicine physician records with a practice address in Michigan. 75% of them appear in a Medicare file (Part D prescribing, MIPS, Open Payments or Medicare group billing); this one does. Its NPI, issued in 2006, is newer than 11% of them.
- NPI issued2006 · 11% of these records are older, 56% newer
- In a Medicare fileYes · 75% of these records are
- In the CMS Doctors and Clinicians fileNo · 58% of these records are
- Record last updated2016 · 58% of these records were not updated in five years or more
Source: CMS NPPES, file of Aug 9, 2026, every record with primary taxonomy 207Q00000X and a Michigan practice address; Medicare files: CMS Part D Prescribers 2024, MIPS 2023, Open Payments 2024, Doctors and Clinicians (data.cms.gov).
30 family medicine physician records list a practice address in Portage
They are 30 of the 1,492 NPPES records with a practice address in Portage, and 6,013 family medicine physician records in Michigan.
All 6,013 in Michigan → Every provider in Portage → Family Medicine Physician nationwide →
The 8 family medicine physician records with the nearest ZIP codes
- Duncan Chapman, MDPortage, MI 490021437474152
- Brandon Manderle, MDPortage, MI 490021013576271
- Remnant Mwanahiba, MDPortage, MI 490021043668650
- Nicole Ognjanovski, MDPortage, MI 490021427610518
- Al PinonPortage, MI 490021669580981
- Abigail Richeson, D.O.Portage, MI 490021427435320
- Ismael Soto Rivas, M.D.Portage, MI 490021699787556
- Jeffrey Stevens, D.O.Portage, MI 490021992769285
Common questions
What is Dietmar J. Grentz, MD's NPI number?
Dietmar J. Grentz, MD's National Provider Identifier (NPI) is 1346269586, issued on Jul 19, 2006. An NPI identifies a provider in billing; it is not a license.
Where is Dietmar J. Grentz, MD located?
The NPPES record lists a practice address at 2725 Airview Blvd, Portage, MI, 49002. Phone: (269) 349-8386. Providers update this record themselves, so call before visiting.
How can I verify Dietmar J. Grentz, MD's license?
NPPES lists Michigan license number 4301069296, as entered by the provider. Search the Michigan Board of Medicine (LARA) at https://aca-prod.accela.com/MILARA/GeneralProperty/PropertyLookUp.aspx?isLicensee=Y&TabName=APO. The NPPES record confirms identity only; the state search shows license status, expiration and public orders.
How much does Dietmar J. Grentz, MD prescribe under Medicare Part D?
In 2024, Dietmar J. Grentz, MD had 8,159 Medicare Part D claims for 128 beneficiaries; the average among family medicine physician prescribers was 3,544. Part D covers Medicare prescriptions only.
Source: CMS National Plan and Provider Enumeration System (NPPES), file of Aug 9, 2026 (NPPES files on CMS.gov); NUCC Health Care Provider Taxonomy. Medicare files from data.cms.gov. An NPI identifies who bills; it is not a license.
Figures on PlainDoctor are read from the federal files each page names (CMS NPPES, Medicare Part D, MIPS, Open Payments; the HHS-OIG exclusion list only as counts) and from Census population estimates, with the file date shown beside them. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of Aug 9, 2026.