Mark O'Connor, M.D.
NPI 1518300284 · Endocrinology, Diabetes & Metabolism Physician · Worcester, MA
Enrolled with Medicare as Practitioner - Endocrinology · source: CMS PECOS Public Provider Enrollment (2026.04.01)
Mark O'Connor, M.D. is a Endocrinology, Diabetes & Metabolism Physician provider in Worcester, MA (NPI 1518300284).
Provider details
- NPI number
- 1518300284
- Entity type
- Individual
- Primary specialty
- Endocrinology, Diabetes & Metabolism PhysicianAllopathic & Osteopathic Physicians
- Credential
- M.D.
- Sex
- Male
- Sole proprietor
- No
- License
- 266640 (MA)
Specialties & taxonomies
Allopathic & Osteopathic Physicians
Profile Score
A profile completeness & documented-activity index — NOT a quality, outcomes, or patient-satisfaction rating.
- Registry tenure28% of score
13 yrs in NPPES registry
- Profile completeness28% of score
100% of core fields populated
- Practice footprint17% of score
2 documented practice locations
- Medicare service volume (vs. specialty peers)28% of score
489 Medicare services, 2024 (ranked within specialty)
Medicare volume is ranked against active providers in the same specialty. 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 does (Medicare)
Based on Medicare fee-for-service claims, 2024; not all care is captured.
| Service (HCPCS) | Medicare services | Typical Medicare-allowed (2024) |
|---|---|---|
| Established Patient Office Or Other Outpatient Visit With Moderate Level of Decision Making, If Using Time, 30 Minutes Or More99214 | 304 | $96 |
| Continuous Monitoring of Blood Sugar Level in Tissue Fluid Using Sensor Under Skin With Interpretation and Report95251 | 72 | $34 |
| New Patient Office Or Other Outpatient Visit With Moderate Level of Medical Decision Making, If Using Time, 45 Minutes Or More99204 | 39 | $132 |
| Visit Complexity Inherent to Evaluation and Management Associated With Medical Care Services That Serve As the Continuing Focal Point for All Needed Health Care Services And/Or With Medical Care Services That Are Part of Ongoing Care Related to a Patient'SG2211 | 28 | $16 |
| Established Patient Office Or Other Outpatient Visit With High Level of Medical Decision Making, If Using Time, 40 Minutes Or More99215 | 23 | $138 |
What this provider prescribes (Medicare Part D)
Top drugs by Medicare Part D claim volume, 2024 · 60 distinct drugs on file.
| Drug | Part D claims (2024) | Beneficiaries |
|---|---|---|
| Semaglutidebrand: Ozempic | 381 | 78 |
| Dulaglutidebrand: Trulicity | 365 | 83 |
| Empagliflozinbrand: Jardiance | 338 | 80 |
| Metformin Hclbrand: Metformin Hcl Er | 272 | 81 |
| Glipizidebrand: Glipizide Er | 200 | 63 |
| Metformin Hcl | 196 |
Practice location
Mailing address
Additional practice locations (1)
- 100 Hospital RdLeominster, MA 01453-2253Phone: (978) 466-4580Fax: (978) 466-4585
Registry dates
- Enumerated
- 2013-04-12
- Last updated
- 2021-03-30
- Certified
- 2021-03-30
Frequently asked questions
- What is Mark O'Connor's NPI number?
- Mark O'Connor's National Provider Identifier (NPI) is 1518300284, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is Mark O'Connor's specialty?
- Mark O'Connor is listed in the NPPES registry with a primary specialty of Endocrinology, Diabetes & Metabolism Physician (Allopathic & Osteopathic Physicians).
- Where is Mark O'Connor located?
- Mark O'Connor's practice location on file with NPPES is 55 Lake Ave N, Worcester, MA 01655-0002.
- What is Mark O'Connor's phone number?
- The practice phone number listed in the NPPES registry for Mark O'Connor is (508) 334-3206.
- Does Mark O'Connor accept Medicare?
- Mark O'Connor is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is Mark O'Connor's NPI active?
- Yes — Mark O'Connor's NPI (1518300284) is active in the NPPES registry as of the last update on 2021-03-30.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.