Dr. Marc Michael Grossman, MD
- Medicare services, 2024
- 683
- Medicare patients, 2024
- 656
- Part D claims, 2024
- 445
- Hospital affiliations
- 5
- Industry payments
- $249
- Practice address
- 333 Borthwick Ave, Portsmouth, NH 03801
- Practice phone
- Call (603) 436-5110
- Professional email
- Get professional email
- Personal email
- Get personal email
- Mobile number
- Get mobile number
Primary practice
Find Dr. Grossman'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.
Dr. Marc Michael Grossman is an emergency medicine physician in Portsmouth, New Hampshire
Dr. Grossman practices at Portsmouth Regional Hospital in Portsmouth, New Hampshire, part of HCA Healthcare.
Dr. Grossman's NPI, 1598799025, was assigned on July 10, 2006. Dr. Grossman holds Massachusetts license 281595.
- NPI
- 1598799025NPI Registry (opens in a new tab)
- Medicare PAC ID
- 5092752139
- NPI enumeration date
- July 10, 2006
- NPI status
- Active
- Accepts Medicare assignment
- Yes
- Practice phone
- (603) 436-5110
- Professional email
- Get email
- Personal email
- Get email
- Mobile number
- Get number
- Sex
- Male
- Estimated age
- 55
- Medical school graduation
- 1997
Sources: NPPES NPI Registry (CMS); Dmand AI Professional Profile Data; Dmand AI Affiliation Data; and Doctors and Clinicians National Downloadable File (CMS)
Dr. Marc Michael Grossman practices at Portsmouth Regional Hospital in Portsmouth, New Hampshire
Dr. Grossman's primary practice is Portsmouth Regional Hospital, at 333 Borthwick Ave, Portsmouth, NH 03801 in Rockingham County. The practice phone is (603) 436-5110.
- Portsmouth Regional Hospital333 Borthwick Ave, Portsmouth, NH 03801 · Rockingham CountyPhone(603) 436-5110
Source: Dmand AI Affiliation Data
Dr. Marc Michael Grossman is affiliated with 6 sites of care and 7 medical groups
Dr. Grossman's primary practice is Portsmouth Regional Hospital in Portsmouth, New Hampshire, part of HCA Healthcare. Dr. Grossman is also affiliated with Boston Medical Center. The medical group on file is Emergency Medicine Services of NH. Dmand AI also links Dr. Grossman to 3 more hospitals, 6 medical groups and 1 ambulatory surgery center, each named with a free account.
Sources: Dmand AI Affiliation Data; and Dmand AI Org Hierarchy Data
Dmand AI tracks the EHR system at Dr. Marc Michael Grossman's practice
Dmand AI tracks the electronic health record (EHR) system at each site where Dr. Grossman practices, 6 sites in all. Vendor and product names are available with a free account.
| Site | EHR vendor and product |
|---|---|
| Portsmouth Regional Hospital | Available with a free account |
| +5 more sites and 6 medical groups | Available with a free account |
Source: Dmand AI Technology Install Data
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Dr. Marc Michael Grossman is one of 298 emergency medicine physicians in New Hampshire
Emergency medicine is Dr. Grossman's primary specialty in the NPI Registry, under taxonomy code 207P00000X. Dr. Grossman is licensed in Massachusetts.
Specialties and state licenses
- Emergency medicine, MassachusettsPrimary
Emergency medicine physicians near Dr. Grossman
Counts of emergency medicine physicians 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
Dr. Marc Michael Grossman billed Medicare for 683 services in 2024
CMS data shows 683 Medicare services from Dr. Grossman across 4 procedure codes in 2024, for 656 Medicare patients. Medicare paid $85,616 for them. Every service was in a facility, such as a hospital, rather than an office.
Dr. Grossman's Medicare services by type, 2023 to 2024
- 2023
- 2024
- Office and hospital visits
- 2023: 6032024: 68313%
- Tests and treatments
- 2023: 272024: 0100%
Dr. Grossman compared with the New Hampshire median for emergency medicine physicians, 2024
- Dr. Grossman
- New Hampshire median
- Medicare services
- 683vs 2392.9 times
- Medicare patients
- 656vs 2662.5 times
- Part D claims
- 294vs 446.7 times
Medians across 328 emergency medicine physicians in New Hampshire with Dmand AI profiles that report each measure.
Dr. Grossman's most billed Medicare procedure codes, 2024
CMS publishes codes billed for 11 or more Medicare patients. Each label is the code family; CPT descriptions are licensed by the AMA.
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Sources: Medicare Physician & Other Practitioners - by Provider and Service (CMS), 2024 data; and Dmand AI Peer Benchmarks
Dr. Marc Michael Grossman treated 656 Medicare patients in 2024, average age 75
CMS counts 656 Medicare patients who saw Dr. Grossman in 2024. The largest group is 75 to 84, with 215 patients. 75% of them have high blood pressure, and 75% have high cholesterol. 18% are also on Medicaid. Their average risk score is 1.56, where 1.00 is the Medicare average, so they are sicker than most Medicare patients.
Across all payers, Dmand AI patient panel data puts Dr. Grossman's median patient age at 56, with 53% women.
Dr. Grossman's Medicare patients by age, 2024
Dr. Grossman's Medicare patients by sex, 2024
- Women36255%
- Men29445%
Chronic conditions among Dr. Grossman's Medicare patients, 2024
- High blood pressure75%
- High cholesterol75%
- Arthritis49%
- Anxiety45%
- Ischemic heart disease39%
- Mood disorders38%
- Depression35%
- Atrial fibrillation33%
Share of Medicare patients with each condition. A patient can have several.
Dr. Grossman's patients across all payers
Dmand AI patient panel data covers Medicare, Medicaid and commercial patients.
Patient panel by age, all payers
Median age 56
Patient panel by sex, all payers
- Women53%
- Men47%
Sources: Dmand AI Patient Panel Data; and Medicare Physician & Other Practitioners - by Provider (CMS), 2024 data
Dr. Marc Michael Grossman wrote 445 Medicare Part D claims in 2024
In 2024, Dr. Grossman wrote 445 Medicare Part D claims for 293 patients. 93% of them were for generic drugs. CMS names the drug for 294 of them, across 11 drugs with 11 or more claims each, at $2,025 in total drug cost. In 2023, CMS named 342 claims across 14 drugs.
Dr. Grossman's Part D claims by kind of drug, 2024
- Generic412 claims93%
- Brand-name and other33 claims7%
Dr. Grossman's most prescribed drugs by claims, 2024
CMS names a drug when it has 11 or more claims. Share is of the claims for drugs CMS names.
Drug classes CMS tracks in Dr. Grossman's Part D claims, 2024
- Opioids10%45 of 445 claims
- Antibiotics25%112 of 445 claims
Share of all Part D claims for each drug class CMS reports on. Classes with no claims are left out.
Part D claims for drugs CMS names, 2023 to 2024
- 2023
- 2024
- Claims for drugs CMS names
- 2023: 3422024: 29414%
Drugs named by CMS: 11 in 2024, 14 in 2023.
Sources: Medicare Part D Prescribers - by Provider and Drug (CMS), 2024 data, released May 6, 2026; and Medicare Part D Prescribers - by Provider (CMS), 2024 data
How Dr. Marc Michael Grossman takes part in Medicare
Dr. Grossman 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)
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Dr. Marc Michael Grossman received $249 in industry payments from 2018 to 2023
CMS Open Payments shows 7 general payments to Dr. Grossman from 5 drug and device companies from 2018 to 2023. Food and beverage make up the largest share, 100% of the total. Stryker Corporation paid the most, $115.
General payments to Dr. Grossman by program year, 2018 to 2023
Companies that paid Dr. Grossman the most, 2018 to 2023
Share is of all general payments to this clinician.
Source: Open Payments (CMS), 2025 data, released July 7, 2026
Sources for Dr. Marc Michael Grossman'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 | Dmand AI Affiliation Data |
| Primary practice, affiliations and health system | Dmand AI Affiliation DataDmand AI Org Hierarchy Data |
| Medicare services and procedure codes | Medicare Physician & Other Practitioners - by Provider and Service (CMS) (opens in a new tab) |
| State medians for the same specialty | Dmand AI Peer Benchmarks |
| Medicare patients and the all-payer patient panel | Dmand AI Patient Panel DataMedicare Physician & Other Practitioners - by Provider (CMS) (opens in a new tab) |
| Part D prescribing | Medicare Part D Prescribers - by Provider and Drug (CMS) (opens in a new tab)Medicare Part D Prescribers - by Provider (CMS) (opens in a new tab) |
| 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 Dr. Marc Michael Grossman
Spotted something out of date? Email hello@dmand.ai and we will check the record. Contact details live in the free trial.
What is Dr. Marc Michael Grossman's NPI number?
Dr. Marc Michael Grossman's NPI number is 1598799025. It was assigned on July 10, 2006, and it is active in the NPI Registry.
What kind of doctor is Dr. Marc Michael Grossman?
Dr. Marc Michael Grossman is an emergency medicine physician in Portsmouth, New Hampshire. The primary specialty in the NPI Registry is Emergency Medicine Physician (taxonomy code 207P00000X).
Where does Dr. Marc Michael Grossman practice?
Dr. Grossman practices at 333 Borthwick Ave, Portsmouth, NH 03801. Dr. Grossman's primary practice is Portsmouth Regional Hospital in Portsmouth, New Hampshire, part of HCA Healthcare. Dmand AI also links Dr. Grossman to 3 hospitals, 6 medical groups and 1 ambulatory surgery center.
What is Dr. Marc Michael Grossman's office phone number?
The practice phone on file for Dr. Grossman is (603) 436-5110.
What is Dr. Marc Michael Grossman's medical license number?
Dr. Grossman holds Massachusetts license 281595.
Which hospitals is Dr. Marc Michael Grossman affiliated with?
Dr. Grossman practices at Portsmouth Regional Hospital in Portsmouth, New Hampshire. Dr. Grossman is also affiliated with Boston Medical Center. Dmand AI links Dr. Grossman to 3 more hospitals.
What medical group is Dr. Marc Michael Grossman part of?
Dr. Grossman is linked to Emergency Medicine Services of NH. Dmand AI links Dr. Grossman to 6 more medical groups.
Does Dr. Marc Michael Grossman accept Medicare?
Yes. CMS data shows Dr. Grossman billed Medicare for 683 services in 2024, and Dr. Grossman accepts Medicare assignment.
How many Medicare patients does Dr. Marc Michael Grossman see?
CMS counts 656 Medicare patients who saw Dr. Grossman in 2024, with an average age of 75.
What services does Dr. Marc Michael Grossman bill to Medicare?
In 2024, Dr. Grossman's most billed Medicare services were emergency department visit (99285), emergency department visit (99284) and critical care (99291).
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What drugs does Dr. Marc Michael Grossman prescribe most?
In 2024 Medicare Part D data, Dr. Grossman's most prescribed drugs by claims were Ondansetron ODT, Naproxen and Methylprednisolone.
Has Dr. Marc Michael Grossman received payments from drug or device companies?
CMS Open Payments shows $249 in general payments to Dr. Grossman from 5 companies from 2018 to 2023. The largest total came from Stryker Corporation.
How long has Dr. Marc Michael Grossman been practicing?
Dr. Grossman graduated from medical school in 1997, 29 years ago.
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