Gregory Clark, M.D.
NPI 1053363952 · Endocrinology, Diabetes & Metabolism Physician · Buffalo Grove, IL
Gregory Clark, M.D. is a Endocrinology, Diabetes & Metabolism Physician provider in Buffalo Grove, IL (NPI 1053363952).
Provider details
- NPI number
- 1053363952
- Entity type
- Individual
- Primary specialty
- Endocrinology, Diabetes & Metabolism PhysicianAllopathic & Osteopathic Physicians
- Credential
- M.D.
- Sex
- Male
- Sole proprietor
- Yes
- License
- 336.093729 (IL)
Specialties & taxonomies
Allopathic & Osteopathic Physicians
Profile Score
A profile completeness & documented-activity index — NOT a quality, outcomes, or patient-satisfaction rating.
- Registry tenure33% of score
20 yrs in NPPES registry
- Profile completeness33% of score
100% of core fields populated
- Practice footprint20% of score
1 documented practice location
- Open Payments transparency13% of score
Has Open Payments disclosures (2024)
Signals a provider has no public data for (e.g. Medicare claims) are left out of the score entirely — never counted as zero — so providers without that data are not penalized. See the full formula and weights in our methodology.
What this provider prescribes (Medicare Part D)
Top drugs by Medicare Part D claim volume, 2024 · 5 distinct drugs on file.
| Drug | Part D claims (2024) |
|---|---|
| Insulin Glargine,hum.rec.anlogbrand: Lantus Solostar | 25 |
| Semaglutidebrand: Ozempic | 19 |
| Insulin Glargine,hum.rec.anlogbrand: Basaglar Kwikpen U-100 | 15 |
| Empagliflozinbrand: Jardiance | 14 |
| Dapagliflozin Propanediolbrand: Farxiga | 11 |
Medicare Part D only. These counts cover prescriptions paid through Medicare Part D in 2024 — they do notinclude cash-pay, commercial-insurance, Medicaid, or Part B–administered drugs, and badly undercount high cash-pay categories (e.g. GLP-1 weight-loss, testosterone, and ED medications). Any drug with 10 or fewer claims is omitted by CMS, and beneficiary counts under 11 are suppressed — so a missing drug means no Part D record, never zero. This is a factual claims summary, not an endorsement, not medical advice, and not a consumer report. Source: CMS Medicare Part D Prescribers — by Provider and Drug.
Transparency — industry payments
Based on CMS Open Payments, 2024; not all care is captured.
$426 across 8 records (Open Payments 2024)
Open Payments discloses payments and transfers of value (meals, travel, consulting, research, royalties) from drug and device makers to providers. This is a transparency signal, not a verdict — such payments are legal and common, and their presence is neither an endorsement nor a criticism. Source: CMS Open Payments, program year 2024.
Practice location
Mailing address
Registry dates
- Enumerated
- 2006-05-17
- Last updated
- 2023-07-26
- Certified
- 2023-07-26
Frequently asked questions
- What is Gregory Clark's NPI number?
- Gregory Clark's National Provider Identifier (NPI) is 1053363952, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is Gregory Clark's specialty?
- Gregory Clark is listed in the NPPES registry with a primary specialty of Endocrinology, Diabetes & Metabolism Physician (Allopathic & Osteopathic Physicians).
- Where is Gregory Clark located?
- Gregory Clark's practice location on file with NPPES is 355 W Dundee Rd Ste 110, Buffalo Grove, IL 60089-3500.
- What is Gregory Clark's phone number?
- The practice phone number listed in the NPPES registry for Gregory Clark is (847) 541-4878.
- Is Gregory Clark's NPI active?
- Yes — Gregory Clark's NPI (1053363952) is active in the NPPES registry as of the last update on 2023-07-26.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.