Kathryn Grinnen, DO
Internal Medicine Physician · Lewes, DE
Kathryn Grinnen, DO is an internal medicine physician with a practice address in Lewes, Delaware, and NPI 1710102124, issued on Apr 13, 2007. Check the license (Delaware C2-0009051, as entered in NPPES) on the Delaware Board of Medical Licensure and Discipline; the Medicare figures below come from public CMS files.
- Name
- Kathryn Grinnen
- Credential
- DO
- Primary taxonomy
- Internal Medicine Physician 207R00000X
- License numbers
- C2-0009051 DE
58002204 OH
Self-reported in NPPES; status is on the state search - Practice location
- 16295 Willow Creek RD, Lewes, DE 19958
- Phone
- (302) 645-3555
- Enumerated
- Apr 13, 2007
- Record last updated
- Feb 10, 2011 (not updated in 15 years: call before relying on the address or phone)
- Medicare enrollment
- Enrolled (PECOS I20090904000452); accepts Medicare assignment
- Medical or professional school
- Lake Erie College Of Osteopathic Medicine, Erie, 2006
- Telehealth
- Offers telehealth (CMS)
- Entity
- Type 1 · individual
8 nearest internal medicine physician records → All 600 in Delaware → Look up another NPI →
Also registered at 16295 Willow Creek RD
A shared address usually means a shared clinic or building; it does not show who employs whom.
- Svetlana Agapov, A-GNP-CGerontology Nurse Practitioner1952088668
- Pamela Blondin, ACNP-BCAcute Care Nurse Practitioner1467820415
- Praveen George, MDCardiovascular Disease Physician1285052605
- Zeina Jeha, MDInternal Medicine Physician1669473641
- Susan Parks, FNP-BCNurse Practitioner1841683331
- Sarah Robinson, DNP, FNP-BCFamily Nurse Practitioner1821639402
Verify Kathryn Grinnen in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersDelaware Board of Medical Licensure and Discipline
Search for license C2-0009051Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
45% more Medicare Part D claims than the average internal medicine physician in 2024
4,612 Medicare Part D claims for 436 beneficiaries, against an average of 3,176 among the 108,855 providers of this specialty who prescribed in Part D. Brand-name drugs were 14% of claims. 124 claims were for opioids.
Most prescribed
- Atorvastatin Calcium213 claims
- Levothyroxine Sodium138 claims
- Rosuvastatin Calcium123 claims
- Amlodipine Besylate113 claims
- Gabapentin101 claims
- Omeprazole94 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.
Industry payments in 2024: $115.80
1 payment: food and beverage; the largest payer was Amgen Inc. The 50,334 providers of this specialty with any payment received $1,303.06 on average. Payments are reported by manufacturers, not by the provider, and are not a sign of wrongdoing.
Source: CMS Open Payments, program year 2024 (openpaymentsdata.cms.gov); average among providers of this specialty with at least one payment.
Bills Medicare through one group practice
- Core Concierge Primary Care And Wellness LLCRehoboth Beach, DE
Source: CMS Doctors and Clinicians National Downloadable File (the group practices a clinician bills Medicare through) (data.cms.gov).
Kathryn Grinnen among 600 internal medicine physician records in Delaware
Kathryn Grinnen, DO is one of 600 internal medicine physician records with a practice address in Delaware. 83% of them appear in a Medicare file (Part D prescribing, MIPS, Open Payments or Medicare group billing); this one does. Its NPI, issued in 2007, is newer than 33% of them.
- NPI issued2007 · 33% of these records are older, 60% newer
- In a Medicare fileYes · 83% of these records are
- In the CMS Doctors and Clinicians fileYes · 69% of these records are
- Graduated2006 · median 2008 among the 414 with a school on file
- Record last updated2011 · 49% of these records were not updated in five years or more
Source: CMS NPPES, file of Aug 9, 2026, every record with primary taxonomy 207R00000X and a Delaware practice address; Medicare files: CMS Part D Prescribers 2024, MIPS 2023, Open Payments 2024, Doctors and Clinicians (data.cms.gov).
43 internal medicine physician records list a practice address in Lewes
They are 43 of the 1,696 NPPES records with a practice address in Lewes, and 600 internal medicine physician records in Delaware.
All 600 in Delaware → Every provider in Lewes → Internal Medicine Physician nationwide →
The 8 internal medicine physician records with the nearest ZIP codes
- Anthony Buonanno, M.D.Lewes, DE 199581609873413
- Linda Choy, M.D.Lewes, DE 199581437104817
- Julie Holmon, M.D.Lewes, DE 199581871580696
- Zeina Jeha, MDLewes, DE 199581669473641
- Afshin Khams, MDLewes, DE 199581669440194
- Imtiaz Khokhar, M.D.Lewes, DE 199581629075387
- Bhaskar Palekar, M.D.Lewes, DE 199581750329322
- Gary Raffel, D.O.Lewes, DE 199581396747432
Common questions
What is Kathryn Grinnen, DO's NPI number?
Kathryn Grinnen, DO's National Provider Identifier (NPI) is 1710102124, issued on Apr 13, 2007. An NPI identifies a provider in billing; it is not a license.
Where is Kathryn Grinnen, DO located?
The NPPES record lists a practice address at 16295 Willow Creek RD, Lewes, DE, 19958. Phone: (302) 645-3555. Providers update this record themselves, so call before visiting.
How can I verify Kathryn Grinnen, DO's license?
NPPES lists Delaware license number C2-0009051, as entered by the provider. Search the Delaware Board of Medical Licensure and Discipline at https://delpros.delaware.gov/OH_VerifyLicense. The NPPES record confirms identity only; the state search shows license status, expiration and public orders.
How much does Kathryn Grinnen, DO prescribe under Medicare Part D?
In 2024, Kathryn Grinnen, DO had 4,612 Medicare Part D claims for 436 beneficiaries; the average among internal medicine physician prescribers was 3,176. Part D covers Medicare prescriptions only.
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.