Mark J. O'Connor, M.D.
Cardiovascular Disease Internal Medicine
Mark J. O'Connor is a Cardiovascular Disease Internal Medicine specialist based in Leominster, MA with over 14 years of clinical experience. Medicare-enrolled per CMS records and offers virtual telehealth visits.
Mark J. O'Connor, M.D. specializes in internal medicine, serving patients in Leominster, MA in group practice. He graduated from University of Massachusetts Medical School in 2012 and has 14+ years of clinical experience. Among his Medicare patients, common conditions include hypertension, high cholesterol, and ischemic_heart (per CMS data).
At a glance
- Uses generic medications more than 31% of reporting doctors in Massachusetts
- Virtual visits available — no app or travel required
Older · 256dNPPES updated 2025-09-10 · verify NPI on CMS · Verify license at Massachusetts Board of Registration in Medicine
Contact & Location
Practice Location
100 Hospital Rd, Leominster, MA 01453-2253
How Does This Doctor Compare?
Based on Medicare data, this doctor favors affordable generic drugs over brand-name ones.
Generic Rx
↑ Higher = better82.6%
Massachusetts avg: 81.9 · US avg: 82.8
⚠ Lower than most doctors nationally(-0.2 pts)
How often this doctor prescribes affordable generic drugs instead of expensive brand-name ones.
Medicare Patients
1,483
Unique beneficiaries
High volumePrescription Recipients
656
Patients prescribed
Prescriptions Written
3,911
Total claims
Total Medicare drug cost: $869k
Percentile rankings compared against 1,606 reporting peers in Massachusetts.
Data Note: Sourced from CMS Medicare Provider Utilization & Payment Data. Percentile rankings compare this provider against all peers with reported data in the same state. Updated annually to reflect the latest federal reporting cycle.
What This Doctor Treats Most
Based on Medicare claims data — here's what patients commonly see this doctor for
Based on Medicare data, this doctor primarily manages Hypertension, High Cholesterol, and Ischemic Heart Disease.
High blood pressure — a leading risk factor for heart disease and stroke
US avg: 70.2%↑ More patients than average (+5%) — a focus area for this doctor
Elevated cholesterol or triglycerides that increase heart disease risk
US avg: 70.4%↑ More patients than average (+5%) — a focus area for this doctor
Reduced blood flow to the heart muscle, commonly known as coronary artery disease
US avg: 31.7%↑ More patients than average (+15%) — a focus area for this doctor
Joint inflammation causing pain, swelling, and stiffness
US avg: 49.3%↓ Fewer patients than average (-2%) — less common here
Gradual loss of kidney function over time, often linked to diabetes or hypertension
US avg: 29.6%↑ More patients than average (+9%) — a focus area for this doctor
A condition where the body cannot properly regulate blood sugar levels
US avg: 34.5%↑ More patients than average (+2%) — a focus area for this doctor
Excessive worry or fear that interferes with daily life
US avg: 34.1%↑ More patients than average (+2%) — a focus area for this doctor
Conditions affecting emotional state, including depression and bipolar disorder
Percentage of this provider's Medicare patients diagnosed with each condition. Source: CMS Utilization Data.
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Background & Specialty
Education, training, and specialty classification from CMS NPPES and Medicare records.
Graduated medical school · 2012
Umass Chan Medical School
Board certified · Sep 9, 2025
Self-reported via NPPES
14 years in practice
Established
Cardiologists specialize in diagnosing and treating heart and blood vessel conditions including coronary artery disease, heart failure, arrhythmias, valve disorders, and hypertension. They perform diagnostic procedures such as echocardiograms, stress tests, and cardiac catheterization.
Taxonomy: 207RC0000X
Education & Training
University of Massachusetts Medical School (Class of 2012)
Mailing address
Po Box 415348, Boston, MA 02241-5348
Differs from practice location
Virtual Cardiovascular Disease Care With Mark J. O'Connor
NPPES records indicate this provider offers telehealth services. Contact the office to confirm availability and scheduling.
Schedule a virtual visit with Mark J. O'Connor for blood pressure monitoring, cholesterol management, follow-up consultations — no travel to Leominster required. The office sends a secure video link before your appointment. Most visits take 15–30 minutes. Medicare enrolled per CMS records.
Frequently Asked Questions
Common questions about Mark J. O'Connor
NPI records show Dr. O'Connor as active with telehealth listed in Leominster, MA. NPI status alone doesn't confirm open availability — call the office to confirm. Phone: (978) 466-2052.
Sourced from CMS NPPES · OIG LEIE · CMS Medicare Part D · CMS Physician Comparator. See Data Methodology.
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Contact Mark J. O'Connor
Practice Location
100 Hospital Rd, Leominster, MA 01453-2253
Mailing Address
Po Box 415348, Boston, MA 02241-5348
This is a provider directory. Contact the office directly to schedule appointments.
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