Gary David Koenig, M.D.
Gastroenterology Physician · Hazelwood, MO
Gary David Koenig, M.D. is a gastroenterology physician with a practice address in Hazelwood, Missouri, and NPI 1861485724, issued on Aug 25, 2005. Check the license (Missouri MDR3G44, as entered in NPPES) on the Missouri Board of Registration for the Healing Arts; the Medicare figures below come from public CMS files.
- Name
- Gary David Koenig
- Credential
- M.D.
- Primary taxonomy
- Gastroenterology Physician 207RG0100X
- License numbers
- MDR3G44 MO
RG344 MO
Self-reported in NPPES; status is on the state search - Practice location
- 100 Village SQ, Hazelwood, MO 63042
- Phone
- (314) 355-4010
- Enumerated
- Aug 25, 2005
- Record last updated
- Feb 16, 2026
- Fax
- (314) 355-9484
- Medicaid ID
- 202823316 MO
- Medicare enrollment
- Enrolled (PECOS I20090803000025); accepts Medicare assignment
- Medical or professional school
- Saint Louis University School Of Medicine, 1986
- Entity
- Type 1 · individual
8 nearest gastroenterology physician records → All 414 in Missouri → Look up another NPI →
Also registered at 100 Village SQ
A shared address usually means a shared clinic or building; it does not show who employs whom.
- Robyn Haithcock, DOGastroenterology Physician1497751994
- David Landau, MDGastroenterology Physician1861485476
- David Margolis, MDGastroenterology Physician1538152301
- Tomma Stowers, AGNPAdult Health Nurse Practitioner1225535263
Verify Gary David Koenig in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersMissouri Board of Registration for the Healing Arts
Search for license MDR3G44Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
84% more Medicare Part D claims than the average gastroenterology physician in 2024
1,491 Medicare Part D claims for 962 beneficiaries, against an average of 811 among the 16,445 providers of this specialty who prescribed in Part D. Brand-name drugs were 20% of claims.
Most prescribed
- Gavilyte-G375 claims
- Sod Sulf-Potass Sulf-Mag Sulf290 claims
- Omeprazole192 claims
- Pantoprazole Sodium63 claims
- Gavilyte-C55 claims
- Linzess49 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.
The practice group's MIPS final score for 2023 (Medicare payment program): 62.3 of 100
The Merit-based Incentive Payment System score is reported for the practice group, not for one clinician alone. Four categories are weighted into the final score; the average among 454,083 clinicians with a measured score was 83.5.
Source: CMS Quality Payment Program, MIPS performance year 2023, group reporting; category weights for 2023 (qpp.cms.gov).
Industry payments in 2024: $3,396.09
185 payments; by number, the most common kind was food and beverage; the largest payer was Abbvie Inc. The 13,350 providers of this specialty with any payment received $5,015.95 on average. Payments are reported by manufacturers, not by the provider, and are not a sign of wrongdoing.
Source: CMS Open Payments, program year 2024 (openpaymentsdata.cms.gov); average among providers of this specialty with at least one payment.
Bills Medicare through 2 group practices
- Mercy Clinic Gastroenterology LLCWashington, MO
- Physician Groups LCSaint Peters, MO
Source: CMS Doctors and Clinicians National Downloadable File (the group practices a clinician bills Medicare through) (data.cms.gov).
Gary David Koenig among 414 gastroenterology physician records in Missouri
Gary David Koenig, M.D. is one of 414 gastroenterology physician records with a practice address in Missouri. 84% of them appear in a Medicare file (Part D prescribing, MIPS, Open Payments or Medicare group billing); this one does. Its NPI, issued in 2005, is newer than 0% of them.
- NPI issued2005 · 0% of these records are older, 86% newer
- In a Medicare fileYes · 84% of these records are
- In the CMS Doctors and Clinicians fileYes · 73% of these records are
- Graduated1986 · median 2003 among the 303 with a school on file
- Record last updated2026 · 47% of these records were not updated in five years or more
Source: CMS NPPES, file of Aug 9, 2026, every record with primary taxonomy 207RG0100X and a Missouri practice address; Medicare files: CMS Part D Prescribers 2024, MIPS 2023, Open Payments 2024, Doctors and Clinicians (data.cms.gov).
4 gastroenterology physician records list a practice address in Hazelwood
They are 4 of the 301 NPPES records with a practice address in Hazelwood, and 414 gastroenterology physician records in Missouri.
All 414 in Missouri → Every provider in Hazelwood → Gastroenterology Physician nationwide →
The 8 gastroenterology physician records with the nearest ZIP codes
- Robyn Haithcock, DOHazelwood, MO 630421497751994
- David Landau, MDHazelwood, MO 630421861485476
- David Margolis, MDHazelwood, MO 630421538152301
- Patrick McDonough, MDBridgeton, MO 630441770791832
- Raymond Mohrman, MDBridgeton, MO 630441063516375
- Melvin Saltzman, D.O.Bridgeton, MO 630441124025416
- Shanker Das Kundumadam, MDFestus, MO 630281720475403
- Rehan Rafiq, M.D.Festus, MO 630281407924954
Common questions
What is Gary David Koenig, M.D.'s NPI number?
Gary David Koenig, M.D.'s National Provider Identifier (NPI) is 1861485724, issued on Aug 25, 2005. An NPI identifies a provider in billing; it is not a license.
Where is Gary David Koenig, M.D. located?
The NPPES record lists a practice address at 100 Village SQ, Hazelwood, MO, 63042. Phone: (314) 355-4010. Providers update this record themselves, so call before visiting.
How can I verify Gary David Koenig, M.D.'s license?
NPPES lists Missouri license number MDR3G44, as entered by the provider. Search the Missouri Board of Registration for the Healing Arts at https://www.fsmb.org/contact-a-state-medical-board/. The NPPES record confirms identity only; the state search shows license status, expiration and public orders.
How much does Gary David Koenig, M.D. prescribe under Medicare Part D?
In 2024, Gary David Koenig, M.D. had 1,491 Medicare Part D claims for 962 beneficiaries; the average among gastroenterology physician prescribers was 811. Part D covers Medicare prescriptions only.
What is Gary David Koenig, M.D.'s MIPS final score?
The 2023 MIPS final score is 62.3 of 100, reported for the practice group. The average among 454,083 clinicians with a measured score was 83.5.
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.