NPI registry status
Active
2026 NPPES data Specialist NPI 1033158795 M.D.
Verify on CMS → Leo Cass, M.D.
Specialist in Winchester, 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 69,608 in Specialist, 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
4K
Medicare Part D claims · 62 beneficiaries · Specialist avg: 1K
Compiled from official public sources by the PlainDoctor editorial team.
What the federal data shows
Leo Cass, M.D. filed 4,141 Medicare Part D claims in 2023 as a Specialist in Winchester, Massachusetts.
- 4K
- Part D claims, 2023
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.
Leo Cass, M.D.'s Medicare Part D volume vs every U.S. prescriber
Total Medicare Part D claims, 2023, across all CMS prescribers nationally
4,141 Top 8% higher than 92% 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
What does the federal data show about Leo Cass, M.D.?
Quality data not reportedPrimary specialty
Specialist
Medicare Part D claims
4,141 181% vs specialty avg
Specialty distribution in Massachusetts
How Specialist 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 Specialist. 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).
Leo Cass, M.D. appears in the CMS NPPES registry as a Specialist provider holding M.D. credentials at 223 SWANTON ST, Winchester, MA, 01890, with a listed phone of (781) 721-5025. NPI 1033158795 was issued on 06/06/2006.
Medicare Part D records for calendar year 2023 show 4,141 prescription claims written by this provider, covering 62 Medicare beneficiaries and totaling roughly $98K in drug spend, with an opioid prescribing rate of 1.1%.
Specialist is a high-volume specialty nationwide, with 69,608 enrolled providers across 55 states and an average of 1,474 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 | 1033158795 |
|---|---|
| Specialty | Specialist |
| Credentials | M.D. |
| Gender | Male |
| NPI Issued | 06/06/2006 |
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 Leo Cass, M.D.. To verify Leo Cass, 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.
Medicare Part D Prescribing Data
CMS Medicare Part D prescriber-level data for calendar year 2023.
4,141
Total Claims
$98K
Total Drug Cost
62
Medicare Beneficiaries
Prescribing Breakdown
- 30-Day Fills
- 4,154
- Total Day Supply
- 45,944
- Generic Drug Cost
- $31K
- Opioid Claims
- 44 (1.1% rate)
- Antibiotic Claims
- 76
Patient Demographics
- Average Patient Age
- 79.9 years
- Avg HCC Risk Score
- 1.68
- Gender Split
- 60% female / 40% male
Top Prescribed Drugs (Medicare Part D)
Top drugs by claim count for calendar year 2023. Based on Medicare Part D data only.
What Leo Cass, M.D. prescribes most
Top Medicare Part D drugs by claim count, 2023
- Atorvastatin Calcium
Atorvastatin Calcium
277 claims
- Metoprolol Succinate
Metoprolol Succinate
240 claims
- Sertraline Hcl
Sertraline Hcl
207 claims
- Trazodone Hcl
Trazodone Hcl
169 claims
- Mirtazapine
Mirtazapine
168 claims
- Metformin Hcl
Metformin Hcl
157 claims
- Omeprazole
Omeprazole
151 claims
- Levothyroxine Sodium
Levothyroxine Sodium
143 claims
| Drug | Claims |
|---|---|
| Atorvastatin Calcium | 277 |
| Metoprolol Succinate | 240 |
| Sertraline Hcl | 207 |
| Trazodone Hcl | 169 |
| Mirtazapine | 168 |
| Metformin Hcl | 157 |
| Omeprazole | 151 |
| Levothyroxine Sodium | 143 |
| Furosemide | 140 |
| Tamsulosin Hcl | 139 |
* Counts below 11 are suppressed by CMS for patient privacy. Generic names shown where available from CMS Part D data.
Specialist Overview
How Leo Cass, M.D. fits within the Specialist landscape nationally.
69,608
Specialist Providers in US
55
States with Specialist
1,474
Avg Claims per Provider
Leo Cass, M.D.'s 4,141 claims are above the specialty average of 1,474.
Nearby Specialist Providers in Massachusetts
Other clinicians with the same primary specialty enrolled in Massachusetts, drawn from the same CMS NPPES roster as Cass.
Dr. Bruce Abbott
MD
New Bedford, MA
Dr. Sylvie Abi-Younes
M.D.
Norwood, MA
Dr. Funlola Aboderin
M.D.
Boston, MA
Dr. Henry Abraham
M.D.
Lexington, MA
Dr. Pamela Abrams-Warnick
LICSW
Brockton, MA
Compare Specialist 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 Specialist 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.
Healthcare Guides
Learn more about finding, verifying, and understanding healthcare providers.
How to Find a Doctor
Step-by-step guide to choosing a provider
Verify Credentials
Check NPI, board certification & license status
Medical Specialties Explained
Who treats what and how specialties differ
Understanding Medicare Claims Data
What prescribing data reveals about a provider
In-Network vs Out-of-Network
How insurance networks affect your costs
Telehealth Guide
Virtual care options and coverage in 2026
Explore Massachusetts
Frequently Asked Questions
What is Leo Cass, M.D.'s specialty? ▼
Leo Cass, M.D. specializes in Specialist and practices in Winchester, Massachusetts. Credentials: M.D..
How much does Leo Cass, M.D. prescribe under Medicare Part D? ▼
In 2023, Leo Cass, M.D. wrote 4,141 Medicare Part D claims totaling $98K in drug costs for 62 beneficiaries.
Where is Leo Cass, M.D. located? ▼
Leo Cass, M.D. is located at 223 SWANTON ST, Winchester, MA, 01890. Phone: (781) 721-5025.
What is Leo Cass, M.D.'s NPI number? ▼
Leo Cass, M.D.'s National Provider Identifier (NPI) is 1033158795, issued on 06/06/2006.
Does Leo Cass, M.D. prescribe opioids? ▼
Yes, Leo Cass, M.D. had 44 opioid claims in 2023 with an opioid prescribing rate of 1.1%.
How many Specialist providers are there in the US? ▼
There are 69,608 Specialist providers across 55 states in the US. The average Specialist provider writes 1,474 Medicare Part D claims per year.
What drugs does Leo Cass, M.D. prescribe most often? ▼
Based on 2023 Medicare Part D data, Leo Cass, M.D.'s most frequently prescribed drugs include Atorvastatin Calcium, Metoprolol Succinate, Sertraline Hcl. This reflects Medicare Part D prescriptions only and does not include commercial insurance or other payer types.
Does Leo Cass, M.D. accept Medicare? ▼
Leo Cass, M.D. appears in CMS Medicare data with 4,141 Part D claims and 62 Medicare beneficiaries in 2023. Contact the provider's office directly to confirm current Medicare enrollment and accepted plans.
How can I verify Leo Cass, M.D.'s credentials? ▼
Leo Cass, M.D.'s NPI is 1033158795 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.