Katherine A. Diemer, MD
Family Medicine Physician · Freeport, IL
Katherine A. Diemer, MD is a family medicine physician with a practice address in Freeport, Illinois, and NPI 1396906749, issued on Jun 18, 2008. Check the license (Illinois 125051266, as entered in NPPES) on the Illinois Department of Financial and Professional Regulation; the Medicare figures below come from public CMS files.
- Name
- Katherine A. Diemer
- Credential
- MD
- Primary taxonomy
- Family Medicine Physician 207Q00000X
- License numbers
- 125051266 IL
57640 WI
Self-reported in NPPES; status is on the state search - Practice location
- 1301 Kiwanis Dr, Freeport, IL 61032
- Phone
- (815) 235-1406
- Enumerated
- Jun 18, 2008
- Record last updated
- Dec 18, 2020 (not updated in 6 years: call before relying on the address or phone)
- Medicare enrollment
- Enrolled (PECOS I20100123000153); accepts Medicare assignment
- Medical or professional school
- Rush Medical College Of Rush University, 2006
- Telehealth
- Offers telehealth (CMS)
- Entity
- Type 1 · individual
8 nearest family medicine physician records → All 6,215 in Illinois → Look up another NPI →
Also registered at 1301 Kiwanis Dr
A shared address usually means a shared clinic or building; it does not show who employs whom.
- Joseph Davis, PT, DPTPhysical Therapist1710158233
- Marie Heimerdinger, M.D.Internal Medicine Physician1952400442
- Shannon Lizer, FNPFamily Nurse Practitioner1023100781
- Michael Muise, MDFamily Medicine Physician1659481844
- Audreana Zumdahl, FNP-BCFamily Nurse Practitioner1629870399
Verify Katherine A. Diemer in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersIllinois Department of Financial and Professional Regulation
Search for license 125051266Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
77% more Medicare Part D claims than the average family medicine physician in 2024
6,259 Medicare Part D claims for 495 beneficiaries, against an average of 3,544 among the 117,163 providers of this specialty who prescribed in Part D. Brand-name drugs were 11% of claims. 327 claims were for opioids.
Most prescribed
- Atorvastatin Calcium308 claims
- Lisinopril300 claims
- Amlodipine Besylate229 claims
- Levothyroxine Sodium225 claims
- Hydrocodone-Acetaminophen194 claims
- Metformin Hcl186 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.
Bills Medicare through one group practice
- The Monroe Clinic, Inc.Freeport, IL
Source: CMS Doctors and Clinicians National Downloadable File (the group practices a clinician bills Medicare through) (data.cms.gov).
Katherine A. Diemer among 6,215 family medicine physician records in Illinois
Katherine A. Diemer, MD is one of 6,215 family medicine physician records with a practice address in Illinois. 78% of them appear in a Medicare file (Part D prescribing, MIPS, Open Payments or Medicare group billing); this one does. Its NPI, issued in 2008, is newer than 50% of them.
- NPI issued2008 · 50% of these records are older, 46% newer
- In a Medicare fileYes · 78% of these records are
- In the CMS Doctors and Clinicians fileYes · 60% of these records are
- Graduated2006 · median 2006 among the 3,714 with a school on file
- Record last updated2020 · 54% 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 Illinois practice address; Medicare files: CMS Part D Prescribers 2024, MIPS 2023, Open Payments 2024, Doctors and Clinicians (data.cms.gov).
15 family medicine physician records list a practice address in Freeport
They are 15 of the 480 NPPES records with a practice address in Freeport, and 6,215 family medicine physician records in Illinois.
All 6,215 in Illinois → Every provider in Freeport → Family Medicine Physician nationwide →
The 8 family medicine physician records with the nearest ZIP codes
- Robert Bandera, MDFreeport, IL 610321134199458
- Brian Bennett, MDFreeport, IL 610321780657270
- Kathleen Coe, D.O.Freeport, IL 610321396199162
- Christopher Jelinek, MDFreeport, IL 610321689640005
- Ewa Kalinowska, M.D.Freeport, IL 610321427345438
- James McGath, MDFreeport, IL 610321598916314
- Terry Miller, MDFreeport, IL 610321164498366
- Michael Muise, MDFreeport, IL 610321659481844
Common questions
What is Katherine A. Diemer, MD's NPI number?
Katherine A. Diemer, MD's National Provider Identifier (NPI) is 1396906749, issued on Jun 18, 2008. An NPI identifies a provider in billing; it is not a license.
Where is Katherine A. Diemer, MD located?
The NPPES record lists a practice address at 1301 Kiwanis Dr, Freeport, IL, 61032. Phone: (815) 235-1406. Providers update this record themselves, so call before visiting.
How can I verify Katherine A. Diemer, MD's license?
NPPES lists Illinois license number 125051266, as entered by the provider. Search the Illinois Department of Financial and Professional Regulation at https://idfpr.illinois.gov/checklicense.html. The NPPES record confirms identity only; the state search shows license status, expiration and public orders.
How much does Katherine A. Diemer, MD prescribe under Medicare Part D?
In 2024, Katherine A. Diemer, MD had 6,259 Medicare Part D claims for 495 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.