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 69,567 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
2K
Medicare Part D claims · 17 beneficiaries · Specialist avg: 2K
What the federal data shows
Leo Cass, M.D. filed 2,401 Medicare Part D claims in 2024 as a Specialist in Winchester, Massachusetts.
- 2K
- Part D claims, 2024
- ≥86th
- pct by Part D claim volume (lower-bound band)
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.
Federal trust snapshot
What official records show about Leo Cass, M.D.
Bare NPI registry listing — limited federal enrichment beyond basic enumeration. Verify all credentials with official sources.
- Verified
NPI registry status
Active listing in the CMS National Provider Identifier Registry (NPI 1033158795), first enumerated 06/06/2006.
Source: CMS NPPES
- Reported
Medicare Part D participation
Filed 2,401 Medicare Part D prescription claims in the 2023 CMS public use file — indicates active Medicare prescribing participation.
Source: CMS Part D Prescriber PUF
- State context
State board disciplinary context
Massachusetts statewide board action statistics are published annually — these figures describe aggregate state activity, not Leo Cass, M.D.'s individual license status. Verify directly with the state medical board.
Source: BORIM annual report 2023
- Not in federal data
Individual sanction lookup
PlainDoctor does not publish per-provider disciplinary determinations. Confirm current license and any individual actions through the state medical board or FSMB verification service.
Source: State medical board / FSMB
This trust snapshot summarizes only what appears in federal CMS/NPPES public records. It is not a composite score, star rating, patient review, or clinical recommendation. PlainDoctor never fabricates reviews or AggregateRating schema.
Compare Cass with other Specialist providers
Same primary specialty, same federal CMS NPPES roster.
All 7 Specialist providers in Winchester, MA →
Also enrolled in Massachusetts
- 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
- Pamela Abrams-Warnick, LICSW Brockton, MA
- Janine Acevedo, M.E.C.S.E. Beverly, MA
Other specialties in Winchester: Clinical Social Worker (31) · Internal Medicine Physician (21) · Physical Therapist (20) · Anesthesiology Physician (18)
CMS NPPES provider registry desk
NPI 1033158795 · Specialist
NPI-10 · ENUM-LEGACY · TAX-MEGA · RX-MID · BOOK-LIGHT · PHOTO-ENUM
- NPI-10 1033158795
- ENUM-LEGACY 2006
- TAX-MEGA 70K Specialist
- RX-MID 2,401
- BOOK-LIGHT 1,259 in Massachusetts
- PHOTO-ENUM William Bloomer, M.D. · 2006
Leo Cass, M.D.'s Medicare Part D volume vs every U.S. prescriber
Total Medicare Part D claims, 2024, across all CMS prescribers nationally
2,401 ≥ 86th percentile 86% of 1,416,883 prescribers are in lower value bands
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.
The percentile is a conservative 100-claim band: it counts only prescribers in lower claim-volume bands. Medicare Part D claim volume is activity context, not a quality measure or recommendation. See methodology § corpus placement.
Source CMS Medicare Part D Prescriber Public Use File · 2024
What does the federal data show about Leo Cass, M.D.?
Quality data not reportedPrimary specialty
Specialist
Medicare Part D claims
2,401 58% 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).
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 2024.
2,401
Total Claims
$37K
Total Drug Cost
17
Medicare Beneficiaries
Prescribing Breakdown
- 30-Day Fills
- 2,413
- Total Day Supply
- 20,298
- Generic Drug Cost
- $19K
- Opioid Claims
- 21 (0.9% rate)
- Antibiotic Claims
- 25
Patient Demographics
- Average Patient Age
- 87.2 years
- Avg HCC Risk Score
- 2.03
- Age Distribution
- <65: 0, 65-74: 0, 75-84: N/A, 85+: N/A
Top Prescribed Drugs (Medicare Part D)
Top drugs by claim count for calendar year 2024. Based on Medicare Part D data only.
What Leo Cass, M.D. prescribes most
Top Medicare Part D drugs by claim count, 2024
- Sertraline Hcl
Sertraline Hcl
192 claims
- Metformin Hcl
Metformin Hcl
186 claims
- Atorvastatin Calcium
Atorvastatin Calcium
149 claims
- Metoprolol Succinate
Metoprolol Succinate
148 claims
- Mirtazapine
Mirtazapine
129 claims
- Lisinopril
Lisinopril
107 claims
- Labetalol Hcl
Labetalol Hcl
106 claims
- Torsemide
Torsemide
106 claims
| Drug | Claims |
|---|---|
| Sertraline Hcl | 192 |
| Metformin Hcl | 186 |
| Atorvastatin Calcium | 149 |
| Metoprolol Succinate | 148 |
| Mirtazapine | 129 |
| Lisinopril | 107 |
| Labetalol Hcl | 106 |
| Torsemide | 106 |
| Furosemide | 105 |
| Tamsulosin Hcl | 87 |
* 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.
69,567
Specialist Providers in US
55
States with Specialist
1,524
Avg Claims per Provider
Leo Cass, M.D.'s 2,401 claims are above the specialty average of 1,524.
Nationwide Specialist peers with similar MIPS or enrollment year
Two federal-record peer sets for Cass, both outside Massachusetts so the neighborhoods are not geographic containment.
Same NPPES enumeration year (2006)
Same-specialty clinicians who entered the NPI registry in the same calendar year, outside this state.
Nearby Specialist Providers in Massachusetts
Other clinicians with the same primary specialty enrolled in Massachusetts, drawn from the same CMS NPPES roster as Cass.
One of 1,259 Specialist providers enrolled in Massachusetts, 11 are shown on this page.
Dr. Brian Acker
M.D.
Springfield, MA
Dr. Vincent Agnello
M.D.
Burlington, MA
Patricia Ahearn.burnett
Brockton, MA
Alexandra Ais
Brockton, MA
Dr. Abdallah Alameddine
MD
Springfield, MA
Compare Specialist nationally: see state-by-state distribution →
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 2024, Leo Cass, M.D. wrote 2,401 Medicare Part D claims totaling $37K in drug costs for 17 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 21 opioid claims in 2024 with an opioid prescribing rate of 0.9%.
How many Specialist providers are there in the US? ▼
There are 69,567 Specialist providers across 55 states in the US. The average Specialist provider writes 1,524 Medicare Part D claims per year.
What drugs does Leo Cass, M.D. prescribe most often? ▼
Based on 2024 Medicare Part D data, Leo Cass, M.D.'s most frequently prescribed drugs include Sertraline Hcl, Metformin Hcl, Atorvastatin Calcium. 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 2,401 Part D claims and 17 Medicare beneficiaries in 2024. 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 (2024). 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 August 2026 (NPPES) / 2024 (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
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 August 2026.