Gregory K. Buller, M.D.
Nephrology Physician · Middlebury, CT
Gregory K. Buller, M.D. is a nephrology physician with a practice address in Middlebury, Connecticut, and NPI 1154321768, issued on Jul 26, 2005. Check the license (Connecticut 027195, as entered in NPPES) on the Connecticut Medical Examining Board; the Medicare figures below come from public CMS files.
- Name
- Gregory K. Buller
- Credential
- M.D.
- Primary taxonomy
- Nephrology Physician 207RN0300X
- License number
- 027195 CT
Self-reported in NPPES; status is on the state search - Practice location
- 850 Straits Tpke, Middlebury, CT 06762
- Phone
- (203) 758-1800
- Enumerated
- Jul 26, 2005
- Record last updated
- Sep 3, 2019 (not updated in 7 years: call before relying on the address or phone)
- Fax
- (203) 758-1804
- Medicaid ID
- 001271957 CT
- Medicare enrollment
- Enrolled (PECOS I20080310000600); accepts Medicare assignment
- Entity
- Type 1 · individual
8 nearest nephrology physician records → All 167 in Connecticut → Look up another NPI →
Also registered at 850 Straits Tpke
A shared address usually means a shared clinic or building; it does not show who employs whom.
- Gina Burrows, APRNRegistered Nurse1235282369
- Marilyn Olsen, PAPhysician Assistant1407856917
- Beatriz Olson, MDEndocrinology, Diabetes & Metabolism Physician1871543009
- Sina Raissi, MDNephrology Physician1053311662
- Mira Rho, MDNephrology Physician1093936205
- David Roer, MDNephrology Physician1073513685
Verify Gregory K. Buller in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersConnecticut Medical Examining Board
Search for license 027195Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
98% fewer Medicare Part D claims than the average nephrology physician in 2024
36 Medicare Part D claims, against an average of 1,465 among the 10,986 providers of this specialty who prescribed in Part D.
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 MIPS final score for 2023 (Medicare payment program): 93.3 of 100
The Merit-based Incentive Payment System score is reported for this clinician. 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; category weights for 2023 (qpp.cms.gov).
Industry payments in 2024: $85.92
1 payment: food and beverage; the largest payer was Novartis Pharmaceuticals Corporation. The 8,230 providers of this specialty with any payment received $3,091.37 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 one group practice
- Northeast Medical Group IncBridgeport, CT
Source: CMS Doctors and Clinicians National Downloadable File (the group practices a clinician bills Medicare through) (data.cms.gov).
Gregory K. Buller among 167 nephrology physician records in Connecticut
Gregory K. Buller, M.D. is one of 167 nephrology physician records with a practice address in Connecticut. 83% 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, 70% newer
- In a Medicare fileYes · 83% of these records are
- In the CMS Doctors and Clinicians fileYes · 69% of these records are
- Graduated1980 · median 2002 among the 116 with a school on file
- Record last updated2019 · 60% of these records were not updated in five years or more
Source: CMS NPPES, file of Aug 9, 2026, every record with primary taxonomy 207RN0300X and a Connecticut practice address; Medicare files: CMS Part D Prescribers 2024, MIPS 2023, Open Payments 2024, Doctors and Clinicians (data.cms.gov).
4 nephrology physician records list a practice address in Middlebury
They are 4 of the 253 NPPES records with a practice address in Middlebury, and 167 nephrology physician records in Connecticut.
All 167 in Connecticut → Every provider in Middlebury → Nephrology Physician nationwide →
The 8 nephrology physician records with the nearest ZIP codes
- Sina Raissi, MDMiddlebury, CT 067621053311662
- Mira Rho, MDMiddlebury, CT 067621093936205
- David Roer, MDMiddlebury, CT 067621073513685
- William Handelman, M.D.Torrington, CT 067901609851369
- Michael Kovalchik, M.D.Torrington, CT 067901124003892
- George Sunny Pazhayattil, M.D.Torrington, CT 067901588810055
- Badamkhand Baatarkhuu, M.D.Danbury, CT 068101528334380
- Panupong Lisawat, MDDanbury, CT 068101922254184
Common questions
What is Gregory K. Buller, M.D.'s NPI number?
Gregory K. Buller, M.D.'s National Provider Identifier (NPI) is 1154321768, issued on Jul 26, 2005. An NPI identifies a provider in billing; it is not a license.
Where is Gregory K. Buller, M.D. located?
The NPPES record lists a practice address at 850 Straits Tpke, Middlebury, CT, 06762. Phone: (203) 758-1800. Providers update this record themselves, so call before visiting.
How can I verify Gregory K. Buller, M.D.'s license?
NPPES lists Connecticut license number 027195, as entered by the provider. Search the Connecticut Medical Examining Board at https://www.elicense.ct.gov/Lookup/LicenseLookup.aspx. The NPPES record confirms identity only; the state search shows license status, expiration and public orders.
How much does Gregory K. Buller, M.D. prescribe under Medicare Part D?
In 2024, Gregory K. Buller, M.D. had 36 Medicare Part D claims; the average among nephrology physician prescribers was 1,465. Part D covers Medicare prescriptions only.
What is Gregory K. Buller, M.D.'s MIPS final score?
The 2023 MIPS final score is 93.3 of 100. 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.