NPI registry status
Active
2026 NPPES data Urology Physician NPI 1376530378 M.D.
Verify on CMS → Stefan Karos, M.D.
Urology Physician in Leominster, Massachusetts.
This profile is drawn from the federal National Provider Identifier Registry (CMS NPPES), which lists more than 7 million U.S. healthcare providers - including 13,367 in Urology Physician, and covers specialty classification, practice address, and Medicare Part D prescribing data when reported. According to CMS, every field reflects the provider's official federal registration, see our methodology.
Federal data, no proprietary rating.
We show these CMS records as-is - no composite score, no star rating, no editorial opinion layered on top.
Prescribing volume
510
Medicare Part D claims · 149 beneficiaries · Urology Physician avg: 1K
Generic prescribing
97%
generic claims · 3% brand-name · higher generic rates reduce patient out-of-pocket costs
Source: CMS Medicare Part D Prescriber Public Use File, 2023
Compiled from official public sources by the PlainDoctor editorial team.
What the federal data shows
Stefan Karos, M.D. filed 510 Medicare Part D claims in 2023 as a Urology Physician in Leominster, Massachusetts, prescribing 97% generic.
- 510
- Part D claims, 2023
- 97%
- generic prescribing
Every figure on this page comes straight from federal CMS records (NPPES, Medicare Part D, MIPS, Open Payments) - no proprietary rating or editorial opinion is applied.
Stefan Karos, M.D.'s Medicare Part D volume vs every U.S. prescriber
Total Medicare Part D claims, 2023, across all CMS prescribers nationally
510 Top 34% higher than 66% of 1,370,886 prescribers
Each bar is a band; taller bars hold more prescribers. The dashed line + filled bar mark this entry. Hover or tap any bar for its full count, share, and where it sits relative to this entry.
Source CMS Medicare Part D Prescriber Public Use File · 2023
◑
Board-eligible specialty (heuristic, not verified)
Stefan Karos, M.D. practices in an ABMS-board-eligible specialty but we don't have enough CMS-participation signals to confirm active board-certified status. Consult CertificationMatters.org (the official ABMS public lookup).
What does the federal data show about Stefan Karos, M.D.?
Quality data not reportedPrimary specialty
Urology Physician
Medicare Part D claims
510 60% vs specialty avg
Specialty distribution in Massachusetts
How Urology Physician compares to other specialties among Massachusetts providers
Board certification
Not published by CMS
CMS does not publish a per-provider board-certification field in NPPES. PlainDoctor does not have a reliable per-specialty certification rate to show for Urology Physician. Verify directly:
How MIPS and board certification work
The Merit-based Incentive Payment System (MIPS) scores providers 0–100 across four performance categories: Quality, Cost, Promoting Interoperability, and Improvement Activities, weighted under 42 CFR §414.1380. Reporting is voluntary for many small practices, so absence of a MIPS score is not a quality signal.
Board certification through an ABMS or AOA member board signals voluntary post-licensure examination plus continuous Maintenance of Certification cycles. Verify any individual provider's status through certificationmatters.org (ABMS) or osteopathic.org (AOA).
Stefan Karos, M.D. appears in the CMS NPPES registry as a Urology Physician provider holding M.D. credentials at 50 MEMORIAL DR, Leominster, MA, 01453, with a listed phone of (978) 466-4075. NPI 1376530378 was issued on 10/04/2005.
Medicare Part D records for calendar year 2023 show 510 prescription claims written by this provider, covering 149 Medicare beneficiaries and totaling roughly $16K in drug spend, split 3% brand-name and 97% generic by claim count, with an opioid prescribing rate of 4.5%.
Urology Physician is a mid-sized specialty nationwide, with 13,367 enrolled providers across 54 states and an average of 1,280 Part D claims per prescriber, so the context for interpreting these metrics differs meaningfully from a primary-care baseline.
Important: PlainDoctor is a directory of publicly available government data, not medical advice, a malpractice database, or a quality rating. Inclusion here does not imply a recommendation, and absence of complaints or sanctions on this page does not mean none exist, always verify credentials through the NPPES NPI Registry, your state medical board, and the ABMS or AOA before making healthcare decisions.
Practice Address
Provider Details
| NPI | 1376530378 |
|---|---|
| Specialty | Urology Physician |
| Credentials | M.D. |
| Gender | Male |
| NPI Issued | 10/04/2005 |
License & disciplinary context - Massachusetts BORIM 2023 annual report
Aggregate state board data only, NOT a determination of any individual provider's status. The figures below describe statewide disciplinary activity across all ~38K Massachusetts medical licensees in 2023 - they are NOT specific to Stefan Karos, M.D.. To verify Stefan Karos, M.D.'s current license status, search the BORIM public license lookup directly, or check the Federation of State Medical Boards (FSMB) verification service.
80
Total board actions, Massachusetts 2023
Across 78 cases
2.11
Actions per 1,000 licensees
Massachusetts statewide rate
probation
Most common action type
29 cases
BORIM publishes annual disciplinary statistics as part of public-record reporting under each state's Administrative Procedure Act. See the full breakdown by action type and year on the Massachusetts disciplinary trends page. Cross-checked against FSMB U.S. Medical Regulatory Trends.
Brand vs generic prescribing mix · Generic-heavy
Stefan Karos, M.D. - brand share 3.0%
Urology Physician average
3% brand-name claims vs 97% generic, on 510 2023 Medicare Part D claims.
The federal Medicare Part D Generic Dispensing Rate national benchmark sits near 90% generic / 10% brand for primary-care prescribers, per CMS Office of the Actuary 2024 estimates. Higher brand share is common in specialty prescribing where generic equivalents are not available.
Medicare Part D Prescribing Data
CMS Medicare Part D prescriber-level data for calendar year 2023.
510
Total Claims
$16K
Total Drug Cost
149
Medicare Beneficiaries
Prescribing Breakdown
- 30-Day Fills
- 1,145
- Total Day Supply
- 32,197
- Brand vs Generic
- 3% brand / 97% generic
- Brand Drug Cost
- $3K
- Generic Drug Cost
- $13K
- Opioid Claims
- 23 (4.5% rate)
- Antibiotic Claims
- 66
Patient Demographics
- Average Patient Age
- 74.1 years
- Avg HCC Risk Score
- 1.31
- Gender Split
- 13% female / 87% male
- Age Distribution
- <65: 11, 65-74: 72, 75-84: 51, 85+: 15
Top Prescribed Drugs (Medicare Part D)
Top drugs by claim count for calendar year 2023. Based on Medicare Part D data only.
What Stefan Karos, M.D. prescribes most
Top Medicare Part D drugs by claim count, 2023
- Finasteride
Finasteride
177 claims
- Tamsulosin Hcl
Tamsulosin Hcl
166 claims
- Ciprofloxacin Hcl 40
Ciprofloxacin Hcl
40 claims
- Oxycodone-Acetamin… 21
Oxycodone-Acetaminophen
21 claims
- Nitrofurantoin 13
Nitrofurantoin
13 claims
- Oxybutynin Chloride 13
Oxybutynin Chloride
13 claims
| Drug | Claims |
|---|---|
| Finasteride | 177 |
| Tamsulosin Hcl | 166 |
| Ciprofloxacin Hcl | 40 |
| Oxycodone-Acetaminophen Oxycodone Hcl/Acetaminophen | 21 |
| Nitrofurantoin Nitrofurantoin Macrocrystal | 13 |
| Oxybutynin Chloride | 13 |
* Counts below 11 are suppressed by CMS for patient privacy. Generic names shown where available from CMS Part D data.
Urology Physician Overview
How Stefan Karos, M.D. fits within the Urology Physician landscape nationally.
13,367
Urology Physician Providers in US
54
States with Urology Physician
1,280
Avg Claims per Provider
Stefan Karos, M.D.'s 510 claims are below the specialty average of 1,280.
Nearby Urology Physician Providers in Massachusetts
Other clinicians with the same primary specialty enrolled in Massachusetts, drawn from the same CMS NPPES roster as Karos.
Ahmad Abdel-Aziz
Boston, MA
Dr. Joseph Adolph
MD
Marlboro, MA
Dr. Abdulsalam Albalawi
MD
Chestnut Hill, MA
Dr. Richard Alexander
M.D.
Greenfield, MA
Dr. Ashley Alford
MD
Worcester, MA
Compare Urology Physician nationally: see state-by-state distribution →
Before you book an appointment
Use this federal record as your verification checklist, not as a recommendation.
- Confirm the NPI record is current in the official CMS registry, providers update their own NPPES details, and moves can lag. Verify this NPI
- Check the active license and any disciplinary history with the Massachusetts medical board, federal registration is not a license check. Credential verification guide
- Weigh a second option: compare this provider with a nearby Urology Physician peer on Medicare volume and prescribing patterns. Compare providers
Medicare Part D and MIPS figures describe practice patterns in federal programs only, they are not quality ratings, and PlainDoctor does not rate, rank, or recommend providers.
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Frequently Asked Questions
What is Stefan Karos, M.D.'s specialty? ▼
Stefan Karos, M.D. specializes in Urology Physician and practices in Leominster, Massachusetts. Credentials: M.D..
How much does Stefan Karos, M.D. prescribe under Medicare Part D? ▼
In 2023, Stefan Karos, M.D. wrote 510 Medicare Part D claims totaling $16K in drug costs for 149 beneficiaries.
Where is Stefan Karos, M.D. located? ▼
Stefan Karos, M.D. is located at 50 MEMORIAL DR, Leominster, MA, 01453. Phone: (978) 466-4075.
What is Stefan Karos, M.D.'s NPI number? ▼
Stefan Karos, M.D.'s National Provider Identifier (NPI) is 1376530378, issued on 10/04/2005.
Does Stefan Karos, M.D. prescribe more brand-name or generic drugs? ▼
Stefan Karos, M.D.'s prescribing is 3% brand-name and 97% generic drugs by claim count, with $3K in brand drug costs.
Does Stefan Karos, M.D. prescribe opioids? ▼
Yes, Stefan Karos, M.D. had 23 opioid claims in 2023 with an opioid prescribing rate of 4.5%.
How many Urology Physician providers are there in the US? ▼
There are 13,367 Urology Physician providers across 54 states in the US. The average Urology Physician provider writes 1,280 Medicare Part D claims per year.
What drugs does Stefan Karos, M.D. prescribe most often? ▼
Based on 2023 Medicare Part D data, Stefan Karos, M.D.'s most frequently prescribed drugs include Finasteride, Tamsulosin Hcl, Ciprofloxacin Hcl. This reflects Medicare Part D prescriptions only and does not include commercial insurance or other payer types.
Does Stefan Karos, M.D. accept Medicare? ▼
Stefan Karos, M.D. appears in CMS Medicare data with 510 Part D claims and 149 Medicare beneficiaries in 2023. Contact the provider's office directly to confirm current Medicare enrollment and accepted plans.
How can I verify Stefan Karos, M.D.'s credentials? ▼
Stefan Karos, M.D.'s NPI is 1376530378 with credentials M.D.. You can verify this through the NPPES NPI Registry, check state medical board records, and confirm board certification through the ABMS or AOA.
Data Sources
View source datasets and methodology notes
- Provider Directory
- CMS National Plan and Provider Enumeration System (NPPES), download.cms.gov/nppes, updated monthly. Contains NPI, specialty, credentials, and practice location.
- Specialty Classification
- NUCC Health Care Provider Taxonomy (nucc.org), the industry standard for classifying provider specialties in Medicare and Medicaid billing.
- Prescribing Data
- CMS Medicare Part D Prescriber Public Use File (2023). Includes claims, drug costs, beneficiaries, and opioid prescribing rates.
- Limitations
- Provider data is self-reported to CMS. Prescribing data reflects Medicare Part D only and does not include commercial insurance, Medicaid, or cash prescriptions. Claims below 11 beneficiaries are suppressed by CMS for privacy.
See our complete data methodology for details on how we collect and process government data.
Data as of April 2026 (NPPES) / 2023 (Medicare Part D). Source: Centers for Medicare & Medicaid Services (CMS).
Disclaimer: Data from CMS NPPES and Medicare Part D. PlainDoctor does not rate or rank providers. Provider information is self-reported and may not be current. Always verify information directly with the provider. About · Methodology
Compiled from official public sources by the PlainDoctor editorial team.
Every figure on PlainDoctor is rendered directly from the federal CMS NPPES registry, Medicare Part D, MIPS, and Open Payments records, no number is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of May 2026.