Dr. Keith D. Marcus, MD
- Medicare services, 2024
- 223
- Medicare patients, 2024
- 110
- Part D claims, 2024
- 357
- Hospital affiliations
- 1
- Industry payments
- $71,587
- Practice address
- One N Atkinson Drive, Ludington, MI 49431
- Practice phone
- Call (231) 843-2591
- Professional email
- Get professional email
- Personal email
- Get personal email
- Mobile number
- Get mobile number
Primary practice
Find Dr. Marcus' professional email, personal email and mobile number
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Dr. Keith D. Marcus is an internist in Ludington, Michigan
Dr. Marcus practices at Corewell Health Ludington Hospital in Ludington, Michigan, part of Corewell Health.
Dr. Marcus' NPI, 1255371365, was assigned on June 7, 2006. Dr. Marcus graduated from University of Iowa, RJ & L Carver College of Medicine in 1985. Dr. Marcus holds Michigan license 4301050045.
- NPI
- 1255371365NPI Registry (opens in a new tab)
- Medicare PAC ID
- 0345259909
- NPI enumeration date
- June 7, 2006
- NPI status
- Active
- Accepts Medicare assignment
- Yes
- Practice phone
- (231) 843-2591
- Professional email
- Get email
- Personal email
- Get email
- Mobile number
- Get number
- Sex
- Male
- Estimated age
- 67
- Medical school graduation
- 1985
Sources: NPPES NPI Registry (CMS); Dmand AI Professional Profile Data; Dmand AI Affiliation Data; and Doctors and Clinicians National Downloadable File (CMS)
Dr. Keith D. Marcus practices at 2 locations in Ludington, Michigan
Dr. Marcus' primary practice is Corewell Health Ludington Hospital, at One N Atkinson Drive, Ludington, MI 49431 in Mason County. The practice phone is (231) 843-2591. Dr. Marcus also practices at Spectrum Health Ludington Hospital, 1 Atkinson Dr, Ludington, MI 49431.
- Corewell Health Ludington HospitalPrimaryOne N Atkinson Drive, Ludington, MI 49431 · Mason CountyPhone(231) 843-2591
- Spectrum Health Ludington Hospital1 Atkinson Dr, Ludington, MI 49431 · Mason CountyPhone(231) 843-2591
Sources: NPPES NPI Registry (CMS); Dmand AI Affiliation Data; and Dmand AI Practice Data
Dr. Keith D. Marcus is affiliated with 1 site of care and 3 medical groups
Dr. Marcus' primary practice is Corewell Health Ludington Hospital in Ludington, Michigan, part of Corewell Health. The medical group on file is Corewell Health Medical Group West. Dmand AI also links Dr. Marcus to 2 more medical groups, 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. Keith D. Marcus' practice
Dmand AI tracks the electronic health record (EHR) system at each site where Dr. Marcus practices. Vendor and product names are available with a free account.
| Site | EHR vendor and product |
|---|---|
| Corewell Health Ludington Hospital | Available with a free account |
| +2 medical groups | Available with a free account |
Source: Dmand AI Technology Install Data
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Dr. Keith D. Marcus is one of 4,804 internists in Michigan
Internal medicine is Dr. Marcus' primary specialty in the NPI Registry, under taxonomy code 207R00000X. Dr. Marcus is licensed in Michigan.
Specialties and state licenses
- Internal medicine, MichiganPrimary
Internists near Dr. Marcus
Counts of internists 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. Keith D. Marcus billed Medicare for 223 services in 2024
CMS data shows 223 Medicare services from Dr. Marcus across 6 procedure codes in 2024, for 110 Medicare patients. Medicare paid $15,985 for them. Every service was in a facility, such as a hospital, rather than an office.
Dr. Marcus' Medicare services by type, 2023 to 2024
- 2023
- 2024
- Office and hospital visits
- 2023: 3412024: 20340%
- Tests and treatments
- 2023: 02024: 20
Dr. Marcus compared with the Michigan median for internists, 2024
- Dr. Marcus
- Michigan median
- Medicare services
- 223vs 42347% below
- Medicare patients
- 110vs 15931% below
- Part D claims
- 118vs 31462% below
Medians across 4,524 internists in Michigan with Dmand AI profiles that report each measure.
Dr. Marcus' 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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Medicare shows one payer. Book a meeting to get commercial claims data for Dr. Marcus and other internists in Michigan.
Sources: Medicare Physician & Other Practitioners - by Provider and Service (CMS), 2024 data; and Dmand AI Peer Benchmarks
Dr. Keith D. Marcus treated 110 Medicare patients in 2024, average age 76
CMS counts 110 Medicare patients who saw Dr. Marcus in 2024. The largest group is 75 to 84, with 39 patients. 75% of them have high blood pressure, and 73% have high cholesterol. 32% are also on Medicaid. Their average risk score is 1.98, 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. Marcus' median patient age at 70, with 56% women.
Dr. Marcus' Medicare patients by age, 2024
Dr. Marcus' Medicare patients by sex, 2024
- Women5853%
- Men5247%
Chronic conditions among Dr. Marcus' Medicare patients, 2024
- High blood pressure75%
- High cholesterol73%
- Arthritis61%
- Mood disorders47%
- Depression45%
- Heart failure39%
- Chronic kidney disease37%
- Diabetes37%
Share of Medicare patients with each condition. A patient can have several.
Dr. Marcus' patients across all payers
Dmand AI patient panel data covers Medicare, Medicaid and commercial patients.
Patient panel by age, all payers
Median age 70
Patient panel by sex, all payers
- Women56%
- Men42%
Sources: Dmand AI Patient Panel Data; and Medicare Physician & Other Practitioners - by Provider (CMS), 2024 data
Dr. Keith D. Marcus wrote 357 Medicare Part D claims in 2024
In 2024, Dr. Marcus wrote 357 Medicare Part D claims for 118 patients. 89% of them were for generic drugs. CMS names the drug for 118 of them, across 8 drugs with 11 or more claims each, at $990 in total drug cost. In 2023, CMS named 135 claims across 7 drugs.
Dr. Marcus' Part D claims by kind of drug, 2024
- Generic316 claims89%
- Brand-name and other41 claims11%
Dr. Marcus' 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. Marcus' Part D claims, 2024
- Antibiotics10%37 of 357 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: 1352024: 11813%
Drugs named by CMS: 8 in 2024, 7 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. Keith D. Marcus takes part in Medicare
Dr. Marcus 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. Keith D. Marcus received $71,587 in industry payments from 2017 to 2025
CMS Open Payments shows 112 general payments to Dr. Marcus from 7 drug and device companies from 2017 to 2025. Speaker and faculty fees make up the largest share, 91% of the total. Abbvie Inc. paid the most, $68,343.
General payments to Dr. Marcus by program year, 2017 to 2025
General payments to Dr. Marcus by kind, 2017 to 2025
- Speaker and faculty fees$65,25091%
- Food and beverage$3,2124%
- Travel and lodging$3,1004%
- Education$250%
Companies that paid Dr. Marcus the most, 2017 to 2025
Share is of all general payments to this clinician.
Source: Open Payments (CMS), 2025 data, released July 7, 2026
Dr. Keith D. Marcus graduated from University of Iowa, RJ & L Carver College of Medicine
Dr. Marcus graduated from University of Iowa, RJ & L Carver College of Medicine in 1985.
- Medical school
Source: Dmand AI Professional Profile Data
Sources for Dr. Keith D. Marcus'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 Affiliation DataDmand AI Practice 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) |
| Training, board certification and memberships | Dmand AI Professional Profile Data |
| 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. Keith D. Marcus
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. Keith D. Marcus' NPI number?
Dr. Keith D. Marcus' NPI number is 1255371365. It was assigned on June 7, 2006, and it is active in the NPI Registry.
What kind of doctor is Dr. Keith D. Marcus?
Dr. Keith D. Marcus is an internist in Ludington, Michigan. The primary specialty in the NPI Registry is Internal Medicine Physician (taxonomy code 207R00000X).
Where does Dr. Keith D. Marcus practice?
Dr. Marcus practices at One N Atkinson Drive, Ludington, MI 49431. Dr. Marcus also practices at 1 Atkinson Dr, Ludington, MI 49431. Dr. Marcus' primary practice is Corewell Health Ludington Hospital in Ludington, Michigan, part of Corewell Health. Dmand AI also links Dr. Marcus to 2 medical groups.
What is Dr. Keith D. Marcus' office phone number?
The practice phone on file for Dr. Marcus is (231) 843-2591.
What is Dr. Keith D. Marcus' medical license number?
Dr. Marcus holds Michigan license 4301050045.
Which hospitals is Dr. Keith D. Marcus affiliated with?
Dr. Marcus practices at Corewell Health Ludington Hospital in Ludington, Michigan.
What medical group is Dr. Keith D. Marcus part of?
Dr. Marcus is linked to Corewell Health Medical Group West. Dmand AI links Dr. Marcus to 2 more medical groups.
Does Dr. Keith D. Marcus accept Medicare?
Yes. CMS data shows Dr. Marcus billed Medicare for 223 services in 2024, and Dr. Marcus accepts Medicare assignment.
How many Medicare patients does Dr. Keith D. Marcus see?
CMS counts 110 Medicare patients who saw Dr. Marcus in 2024, with an average age of 76.
What services does Dr. Keith D. Marcus bill to Medicare?
In 2024, Dr. Marcus' most billed Medicare services were hospital inpatient care (99232), hospital inpatient care (99233) and hospital inpatient care (99239).
Show 4 more questionsShow fewer questions
Where did Dr. Keith D. Marcus go to medical school?
Dr. Marcus graduated from University of Iowa, RJ & L Carver College of Medicine in 1985.
What drugs does Dr. Keith D. Marcus prescribe most?
In 2024 Medicare Part D data, Dr. Marcus' most prescribed drugs by claims were Pantoprazole Sodium, Omeprazole and Potassium Chloride.
Has Dr. Keith D. Marcus received payments from drug or device companies?
CMS Open Payments shows $71,587 in general payments to Dr. Marcus from 7 companies from 2017 to 2025. The largest total came from Abbvie Inc.
How long has Dr. Keith D. Marcus been practicing?
Dr. Marcus graduated from medical school in 1985, 41 years ago.
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