Daniel Patrick O'Brien, M.D.
Gastroenterology Physician · Danbury, CT
Daniel Patrick O'Brien, M.D. is a gastroenterology physician with a practice address in Danbury, Connecticut, and NPI 1518132505, issued on Apr 29, 2008. Check the license (Connecticut 53019, as entered in NPPES) on the Connecticut Medical Examining Board; the Medicare figures below come from public CMS files.
- Name
- Daniel Patrick O'Brien
- Credential
- M.D.
- Primary taxonomy
- Gastroenterology Physician 207RG0100X
- License number
- 53019 CT
Self-reported in NPPES; status is on the state search - Practice location
- 111 Osborne St, Danbury, CT 06810
- Phone
- (203) 739-7038
- Enumerated
- Apr 29, 2008
- Record last updated
- Sep 9, 2014 (not updated in 12 years: call before relying on the address or phone)
- Fax
- (203) 739-1961
- Medicare enrollment
- Enrolled (PECOS I20140625002302); accepts Medicare assignment
- Telehealth
- Offers telehealth (CMS)
- Entity
- Type 1 · individual
8 nearest gastroenterology physician records → All 336 in Connecticut → Look up another NPI →
Also registered at 111 Osborne St
A shared address usually means a shared clinic or building; it does not show who employs whom.
- Clifford Appel, M.D.Gastroenterology Physician1366436065
- Neesha Bastien, PA-CPhysician Assistant1487068482
- Steven Brandwein, M.D.Gastroenterology Physician1174542450
- Jason Costa, M.D.Cardiovascular Disease Physician1588007645
- Charlene Deluca, MS, RD, CDNRegistered Dietitian1285226282
- Cynthia Fiore, PAPhysician Assistant1467051920
Verify Daniel Patrick O'Brien in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersConnecticut Medical Examining Board
Search for license 53019Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
36% fewer Medicare Part D claims than the average gastroenterology physician in 2024
523 Medicare Part D claims for 195 beneficiaries, against an average of 811 among the 16,445 providers of this specialty who prescribed in Part D. Brand-name drugs were 9% of claims.
Most prescribed
- Pantoprazole Sodium181 claims
- Gavilyte-C57 claims
- Omeprazole54 claims
- Famotidine53 claims
- Esomeprazole Magnesium24 claims
- Linzess11 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 MIPS final score for 2023 (Medicare payment program): 94.2 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).
Bills Medicare through one group practice
- Nuvance Health Medical Practice CT IncDanbury, CT
Source: CMS Doctors and Clinicians National Downloadable File (the group practices a clinician bills Medicare through) (data.cms.gov).
Daniel Patrick O'Brien among 336 gastroenterology physician records in Connecticut
Daniel Patrick O'Brien, M.D. is one of 336 gastroenterology physician records with a practice address in Connecticut. 86% 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 64% of them.
- NPI issued2008 · 64% of these records are older, 31% newer
- In a Medicare fileYes · 86% of these records are
- In the CMS Doctors and Clinicians fileYes · 76% of these records are
- Graduated2008 · median 2001 among the 255 with a school on file
- Record last updated2014 · 69% 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 Connecticut practice address; Medicare files: CMS Part D Prescribers 2024, MIPS 2023, Open Payments 2024, Doctors and Clinicians (data.cms.gov).
Gastroenterology Physician providers in Connecticut
There are 336 gastroenterology physician records in Connecticut.
All 336 in Connecticut → Every provider in Danbury → Gastroenterology Physician nationwide →
The 8 gastroenterology physician records with the nearest ZIP codes
- Clifford Appel, M.D.Danbury, CT 068101366436065
- David Barenberg, M.D.Danbury, CT 068101548297633
- Steven Brandwein, M.D.Danbury, CT 068101174542450
- Tyson Collazo, M.D.Danbury, CT 068101801195565
- Scott Estabrook, M.D.Danbury, CT 068101225053051
- Joseph Fiorito, M.D.Danbury, CT 068101730108010
- Gerald Franklin, MDDanbury, CT 068101184658528
- Steven Gorelick, M.D.Danbury, CT 068101972555183
Common questions
What is Daniel Patrick O'Brien, M.D.'s NPI number?
Daniel Patrick O'Brien, M.D.'s National Provider Identifier (NPI) is 1518132505, issued on Apr 29, 2008. An NPI identifies a provider in billing; it is not a license.
Where is Daniel Patrick O'Brien, M.D. located?
The NPPES record lists a practice address at 111 Osborne St, Danbury, CT, 06810. Phone: (203) 739-7038. Providers update this record themselves, so call before visiting.
How can I verify Daniel Patrick O'Brien, M.D.'s license?
NPPES lists Connecticut license number 53019, 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 Daniel Patrick O'Brien, M.D. prescribe under Medicare Part D?
In 2024, Daniel Patrick O'Brien, M.D. had 523 Medicare Part D claims for 195 beneficiaries; the average among gastroenterology physician prescribers was 811. Part D covers Medicare prescriptions only.
What is Daniel Patrick O'Brien, M.D.'s MIPS final score?
The 2023 MIPS final score is 94.2 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.