Gregory T. Brennan, PA-C
- Industry payments
- $18
- Affiliated sites
- 1
- Medical group
- 1
- State licenses
- 2
- Year NPI issued
- 2010
- Practice address
- 111 Grossman Dr, Braintree, MA 02184
- Practice phone
- Call (617) 421-1000
- Professional email
- Get professional email
- Personal email
- Get personal email
- Mobile number
- Get mobile number
Primary practice
Harvard Vanguard Medical Associates
Braintree, Massachusetts
Find Gregory Brennan's professional email, personal email and mobile number
Dmand AI checks each channel through healthcare-specific waterfall enrichment. See what is on file with a free account, with practice phones, licenses and affiliations.
Gregory T. Brennan is a physician assistant in Braintree, Massachusetts
Gregory Brennan practices at Harvard Vanguard Medical Associates in Braintree, Massachusetts.
Gregory Brennan's NPI, 1629300124, was assigned on February 8, 2010. Gregory Brennan holds Massachusetts license PA4313.
- NPI
- 1629300124NPI Registry (opens in a new tab)
- Medicare PAC ID
- 0941326862
- NPI enumeration date
- February 8, 2010
- NPI status
- Active
- Accepts Medicare assignment
- Yes
- Practice phone
- (617) 421-1000
- Professional email
- Get email
- Personal email
- Get email
- Mobile number
- Get number
- Sex
- Male
- Estimated age
- 43
- Medical school graduation
- 2009
Sources: NPPES NPI Registry (CMS); Dmand AI Professional Profile Data; Dmand AI Practice Data; and Doctors and Clinicians National Downloadable File (CMS)
Gregory T. Brennan practices at Harvard Vanguard Medical Associates in Braintree, Massachusetts
Gregory Brennan's primary practice is Harvard Vanguard Medical Associates, at 111 Grossman Dr, Braintree, MA 02184 in Norfolk County. The practice phone is (617) 421-1000.
- Harvard Vanguard Medical Associates111 Grossman Dr, Braintree, MA 02184 · Norfolk CountyPhone(617) 421-1000
Sources: NPPES NPI Registry (CMS); and Dmand AI Practice Data
Gregory T. Brennan is affiliated with 2 sites of care and 1 medical group
Gregory Brennan's primary practice is Harvard Vanguard Medical Associates in Braintree, Massachusetts. The medical group on file is Atrius Health. Dmand AI also links Gregory Brennan to 1 more group practice or clinic, named with a free account.
Sources: NPPES NPI Registry (CMS); Dmand AI Practice Data; and Dmand AI Affiliation Data
Dmand AI tracks the EHR system at Gregory T. Brennan's practice
Dmand AI tracks the electronic health record (EHR) system at each site where Gregory Brennan practices. Vendor and product names are available with a free account.
| Site | EHR vendor and product |
|---|---|
| Harvard Vanguard Medical Associates | Available with a free account |
| +1 more affiliated site | Available with a free account |
Source: Dmand AI Technology Install Data
For health IT teams
Dmand AI maps EHR vendors, IT decision makers and buying committees across each health system and 6.2K+ hospitals, with verified contacts in the same login.
Gregory T. Brennan is one of 3,922 physician assistants in Massachusetts
Physician assistant is Gregory Brennan's primary specialty in the NPI Registry, under taxonomy code 363A00000X. Dmand AI has Gregory Brennan's licenses on file in 2 states: Massachusetts and New Hampshire.
Specialties and state licenses
- Physician assistant, MassachusettsPrimary
- Medical physician assistant, New Hampshire
Physician assistants near Gregory Brennan
Counts of physician assistants with a Dmand AI profile, by place and practice. Each opens the list.
Sources: NPPES NPI Registry (CMS); Dmand AI Professional Profile Data; and Dmand AI Peer Benchmarks
Gregory T. Brennan's patients have a median age of 13
Across all payers, Dmand AI patient panel data puts Gregory Brennan's median patient age at 13, with 43% women.
Gregory Brennan's patients across all payers
Dmand AI patient panel data covers Medicare, Medicaid and commercial patients.
Patient panel by age, all payers
Median age 13
Patient panel by sex, all payers
- Women43%
- Men57%
Source: Dmand AI Patient Panel Data
How Gregory T. Brennan takes part in Medicare
Gregory Brennan accepts Medicare assignment, so Medicare's approved amount is taken as full payment.
- Accepts Medicare assignment
- Yes
Source: Doctors and Clinicians National Downloadable File (CMS)
Gregory T. Brennan received $18 in industry payments in 2025
CMS Open Payments shows 1 general payment to Gregory Brennan from 1 drug or device company in 2025. Food and beverage make up the largest share, 100% of the total. Janssen Pharmaceuticals, Inc paid the most, $18.
Companies that paid Gregory Brennan the most, 2025 to 2025
Share is of all general payments to this clinician.
Source: Open Payments (CMS), 2025 data, released July 7, 2026
Sources for Gregory T. Brennan's profile data
| Data on this page | Source |
|---|---|
| NPI, name, sex, specialty and licenses | NPPES NPI Registry (CMS) (opens in a new tab)Dmand AI Professional Profile Data |
| Practice locations and phone | NPPES NPI Registry (CMS) (opens in a new tab)Dmand AI Practice Data |
| Primary practice, affiliations and health system | NPPES NPI Registry (CMS) (opens in a new tab)Dmand AI Practice DataDmand AI Affiliation Data |
| Medicare patients and the all-payer patient panel | Dmand AI Patient Panel Data |
| MIPS scores, telehealth, assignment and procedure percentiles | Doctors and Clinicians National Downloadable File (CMS) (opens in a new tab) |
| Industry payments | Open Payments (CMS) (opens in a new tab) |
| EHR at each practice site | Dmand AI Technology Install Data |
| Similar physicians | Dmand AI Affiliation Data |
Data last refreshed October 2026Report an inaccuracyRemove my information
FAQ
Frequently asked questions about Gregory T. Brennan
Spotted something out of date? Email hello@dmand.ai and we will check the record. Contact details live in the free trial.
What is Gregory T. Brennan's NPI number?
Gregory T. Brennan's NPI number is 1629300124. It was assigned on February 8, 2010, and it is active in the NPI Registry.
What does Gregory T. Brennan specialize in?
Gregory T. Brennan is a physician assistant in Braintree, Massachusetts. The primary specialty in the NPI Registry is Physician Assistant (taxonomy code 363A00000X).
Where does Gregory T. Brennan practice?
Gregory Brennan practices at 111 Grossman Dr, Braintree, MA 02184. Gregory Brennan's primary practice is Harvard Vanguard Medical Associates in Braintree, Massachusetts. Dmand AI also links Gregory Brennan to 1 group practice or clinic.
What is Gregory T. Brennan's office phone number?
The practice phone on file for Gregory Brennan is (617) 421-1000.
What is Gregory T. Brennan's medical license number?
Gregory Brennan holds Massachusetts license PA4313, one of the licenses on file in 2 states.
Which states has Gregory T. Brennan been licensed in?
Dmand AI has state licenses on file for Gregory Brennan in Massachusetts and New Hampshire.
What medical group is Gregory T. Brennan part of?
Gregory Brennan is linked to Atrius Health.
Does Gregory T. Brennan accept Medicare?
Yes. CMS lists Gregory Brennan as accepting Medicare assignment.
Has Gregory T. Brennan received payments from drug or device companies?
CMS Open Payments shows $18 in general payments to Gregory Brennan from 1 company from 2025 to 2025. The largest total came from Janssen Pharmaceuticals, Inc.
How long has Gregory T. Brennan been practicing?
Gregory Brennan graduated from medical school in 2009, 17 years ago.
Selling to physician assistant practices?
See physician assistants in Massachusetts by site of care and group
Find the practices, groups and hospitals they work with, and the right people to contact at each.
- 30 days free
- Self-serve
- No credit card