Dr. John Constantine Gretes, MD
- Medicare services, 2024
- 1,174
- Medicare patients, 2024
- 434
- Part D claims, 2024
- 3,092
- MIPS score, 2024
- 95
- Hospital affiliations
- 4
- Practice address
- 7519 Hospital Road, Gloucester, VA 23061
- Practice phone
- Call (804) 693-8800
- Professional email
- Get professional email
- Personal email
- Get personal email
- Mobile number
- Get mobile number
Primary practice
Find Dr. Gretes' professional email, personal email and mobile number
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Dr. John Constantine Gretes is a nephrologist in Gloucester, Virginia
Dr. Gretes practices at Riverside Walter Reed Hospital in Gloucester, Virginia, part of Riverside Health System.
Dr. Gretes' NPI, 1043248453, was assigned on June 28, 2006. Dr. Gretes graduated from Duke University School of Medicine in 1972. Dr. Gretes holds Virginia license 0101025205.
- NPI
- 1043248453NPI Registry (opens in a new tab)
- Medicare PAC ID
- 5991722084
- NPI enumeration date
- June 28, 2006
- NPI status
- Active
- Accepts Medicare assignment
- Yes
- Practice phone
- (804) 693-8800
- Professional email
- Get email
- Personal email
- Get email
- Mobile number
- Get number
- Sex
- Male
- Estimated age
- 80
- Medical school graduation
- 1972
Sources: NPPES NPI Registry (CMS); Dmand AI Professional Profile Data; Dmand AI Affiliation Data; and Doctors and Clinicians National Downloadable File (CMS)
Dr. John Constantine Gretes practices at Riverside Walter Reed Hospital in Gloucester, Virginia
Dr. Gretes' primary practice is Riverside Walter Reed Hospital, at 7519 Hospital Road, Gloucester, VA 23061 in Gloucester County. The practice phone is (804) 693-8800.
- Riverside Walter Reed Hospital7519 Hospital Road, Gloucester, VA 23061 · Gloucester CountyPhone(804) 693-8800
Source: Dmand AI Affiliation Data
Dr. John Constantine Gretes is affiliated with 7 sites of care and 2 medical groups
Dr. Gretes' primary practice is Riverside Walter Reed Hospital in Gloucester, Virginia, part of Riverside Health System. Dr. Gretes is also affiliated with Riverside Regional Medical Center. The medical group on file is Riverside Gastroenterology Specialists. Dmand AI also links Dr. Gretes to 2 more hospitals, 2 group practices and clinics, 1 dialysis center and 1 medical group, 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. John Constantine Gretes' practice
Dmand AI tracks the electronic health record (EHR) system at each site where Dr. Gretes practices, 7 sites in all. Vendor and product names are available with a free account.
| Site | EHR vendor and product |
|---|---|
| Riverside Walter Reed Hospital | Available with a free account |
| +6 more sites and 1 medical group | 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 Riverside Health System and 6.2K+ hospitals, with verified contacts in the same login.
Dr. John Constantine Gretes is one of 289 nephrologists in Virginia
Nephrology is Dr. Gretes' primary specialty in the NPI Registry, under taxonomy code 207RN0300X. Dr. Gretes is licensed in Virginia.
Specialties and state licenses
- Nephrology, VirginiaPrimary
Nephrologists near Dr. Gretes
Counts of nephrologists 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. John Constantine Gretes billed Medicare for 1,174 services in 2024
CMS data shows 1,174 Medicare services from Dr. Gretes across 14 procedure codes in 2024, for 434 Medicare patients. Medicare paid $122,572 for them.
Dr. Gretes' Medicare services by type, 2023 to 2024
- 2023
- 2024
- Office and hospital visits
- 2023: 7332024: 86218%
- Tests and treatments
- 2023: 2702024: 2556%
- Other services
- 2023: 02024: 57
Where Dr. Gretes' Medicare services took place, 2024
- In an office22719%
- In a facility94781%
Dr. Gretes compared with the Virginia median for nephrologists, 2024
- Dr. Gretes
- Virginia median
- Medicare services
- 1,174vs 1,227Close to median
- Medicare patients
- 434vs 38712% above
- Part D claims
- 2,805vs 7703.6 times
Medians across 276 nephrologists in Virginia with Dmand AI profiles that report each measure.
Dr. Gretes' 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. Gretes and other nephrologists in Virginia.
Sources: Medicare Physician & Other Practitioners - by Provider and Service (CMS), 2024 data; and Dmand AI Peer Benchmarks
Dr. John Constantine Gretes treated 434 Medicare patients in 2024, average age 76
CMS counts 434 Medicare patients who saw Dr. Gretes in 2024. The largest group is 75 to 84, with 185 patients. 75% of them have chronic kidney disease, and 75% have high blood pressure. 8% are also on Medicaid. Their average risk score is 2.66, 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. Gretes' median patient age at 75, with 52% women.
Dr. Gretes' Medicare patients by age, 2024
Dr. Gretes' Medicare patients by sex, 2024
- Women21550%
- Men21950%
Chronic conditions among Dr. Gretes' Medicare patients, 2024
- Chronic kidney disease75%
- High blood pressure75%
- High cholesterol75%
- Arthritis56%
- Diabetes54%
- Ischemic heart disease37%
- Heart failure35%
- Atrial fibrillation32%
Share of Medicare patients with each condition. A patient can have several.
Dr. Gretes' patients across all payers
Dmand AI patient panel data covers Medicare, Medicaid and commercial patients.
Patient panel by age, all payers
Median age 75
Patient panel by sex, all payers
- Women52%
- Men49%
Sources: Dmand AI Patient Panel Data; and Medicare Physician & Other Practitioners - by Provider (CMS), 2024 data
Dr. John Constantine Gretes wrote 3,092 Medicare Part D claims in 2024
In 2024, Dr. Gretes wrote 3,092 Medicare Part D claims for 433 patients. 94% of them were for generic drugs. CMS names the drug for 2,805 of them, across 42 drugs with 11 or more claims each, at $225,027 in total drug cost. In 2023, CMS named 2,635 claims across 44 drugs.
Dr. Gretes' Part D claims by kind of drug, 2024
- Generic2,898 claims94%
- Brand-name194 claims6%
Dr. Gretes' 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. Gretes' Part D claims, 2024
- Antibiotics1%43 of 3,092 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: 2,6352024: 2,8056%
Drugs named by CMS: 42 in 2024, 44 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
Dr. John Constantine Gretes scored 95 out of 100 in Medicare's MIPS program for 2024
CMS publishes a Merit-based Incentive Payment System (MIPS) score of 95 out of 100 for Dr. Gretes for performance year 2024, reported through an alternative payment model (APM). Dr. Gretes accepts Medicare assignment, so Medicare's approved amount is taken as full payment.
- Accepts Medicare assignment
- Yes
Dr. Gretes' MIPS scores, performance year 2024
- 95of 100Final score
- 92.9of 100Quality
- 95of 100Promoting Interoperability
- 40of 100Improvement Activities
Each score is out of 100. The final score weighs the categories CMS scored for this clinician.
Sources: Doctors and Clinicians National Downloadable File (CMS); and Clinician Public Reporting: Overall MIPS Performance (CMS), 2024 data, released September 10, 2026
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Dr. John Constantine Gretes received $21,045 in industry payments from 2016 to 2025
CMS Open Payments shows 111 general payments to Dr. Gretes from 14 drug and device companies from 2016 to 2025. Speaker and faculty fees make up the largest share, 76% of the total. Mallinckrodt LLC paid the most, $19,725.
General payments to Dr. Gretes by program year, 2016 to 2025
General payments to Dr. Gretes by kind, 2016 to 2025
- Speaker and faculty fees$15,90076%
- Travel and lodging$2,57912%
- Food and beverage$2,08710%
- Education$3352%
- Consulting fees$1441%
Companies that paid Dr. Gretes the most, 2016 to 2025
Share is of all general payments to this clinician.
Source: Open Payments (CMS), 2025 data, released July 7, 2026
Dr. John Constantine Gretes graduated from Duke University School of Medicine
Dr. Gretes graduated from Duke University School of Medicine in 1972.
- Medical school
Source: Dmand AI Professional Profile Data
Sources for Dr. John Constantine Gretes'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)Clinician Public Reporting: Overall MIPS Performance (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. John Constantine Gretes
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. John Constantine Gretes' NPI number?
Dr. John Constantine Gretes' NPI number is 1043248453. It was assigned on June 28, 2006, and it is active in the NPI Registry.
What kind of doctor is Dr. John Constantine Gretes?
Dr. John Constantine Gretes is a nephrologist in Gloucester, Virginia. The primary specialty in the NPI Registry is Nephrology Physician (taxonomy code 207RN0300X).
Where does Dr. John Constantine Gretes practice?
Dr. Gretes practices at 7519 Hospital Road, Gloucester, VA 23061. Dr. Gretes' primary practice is Riverside Walter Reed Hospital in Gloucester, Virginia, part of Riverside Health System. Dmand AI also links Dr. Gretes to 2 hospitals, 2 group practices and clinics, 1 dialysis center and 1 medical group.
What is Dr. John Constantine Gretes' office phone number?
The practice phone on file for Dr. Gretes is (804) 693-8800.
What is Dr. John Constantine Gretes' medical license number?
Dr. Gretes holds Virginia license 0101025205.
Which hospitals is Dr. John Constantine Gretes affiliated with?
Dr. Gretes practices at Riverside Walter Reed Hospital in Gloucester, Virginia. Dr. Gretes is also affiliated with Riverside Regional Medical Center. Dmand AI links Dr. Gretes to 2 more hospitals.
What medical group is Dr. John Constantine Gretes part of?
Dr. Gretes is linked to Riverside Gastroenterology Specialists. Dmand AI links Dr. Gretes to 1 more medical group.
Does Dr. John Constantine Gretes accept Medicare?
Yes. CMS data shows Dr. Gretes billed Medicare for 1,174 services in 2024, and Dr. Gretes accepts Medicare assignment.
What is Dr. John Constantine Gretes' MIPS score?
Dr. Gretes' MIPS final score for performance year 2024 is 95 out of 100, reported through an alternative payment model (APM).
How many Medicare patients does Dr. John Constantine Gretes see?
CMS counts 434 Medicare patients who saw Dr. Gretes in 2024, with an average age of 76.
Show 5 more questionsShow fewer questions
What services does Dr. John Constantine Gretes bill to Medicare?
In 2024, Dr. Gretes' most billed Medicare services were office visit, established patient (99214), dialysis (90960) and office visit, established patient (99213).
Where did Dr. John Constantine Gretes go to medical school?
Dr. Gretes graduated from Duke University School of Medicine in 1972.
What drugs does Dr. John Constantine Gretes prescribe most?
In 2024 Medicare Part D data, Dr. Gretes' most prescribed drugs by claims were Amlodipine Besylate, Carvedilol and Losartan Potassium.
Has Dr. John Constantine Gretes received payments from drug or device companies?
CMS Open Payments shows $21,045 in general payments to Dr. Gretes from 14 companies from 2016 to 2025. The largest total came from Mallinckrodt LLC.
How long has Dr. John Constantine Gretes been practicing?
Dr. Gretes graduated from medical school in 1972, 54 years ago.
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