2026 NPPES data Rheumatology Physician NPI 1285168187 M.D.
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GUY KATZ, M.D.

Rheumatology Physician in BOSTON, Massachusetts. CMS National Plan and Provider Enumeration System profile including specialty classification, practice address, and Medicare prescribing data when reported.

Federal data — no proprietary rating. PlainDoctor publishes the actual CMS NPPES and Medicare records — NPI registration, specialty, practice location, and prescribing data — without a composite score or editorial opinion on top. Every field traces to a federal source.
Prescribing volume
393
Medicare Part D claims · 64 beneficiaries · Rheumatology Physician avg: 2K
Generic prescribing
57%
generic claims · 43% brand-name · higher generic rates reduce patient out-of-pocket costs
Industry payments
$3.8K
4 payments · CMS Open Payments (Sunshine Act)
What the federal data reveals: GUY KATZ, M.D. is a Rheumatology Physician ([object Object]) practicing in BOSTON, Massachusetts with a Medicare Part D prescribing footprint of 393 claims across 64 beneficiaries — 43% brand-name prescribing . Industry payments of $3.8K across 4 transactions are disclosed under CMS Open Payments (Sunshine Act).

What stands out: GUY KATZ, M.D. filed 393 Medicare Part D claims in 2023 across BOSTON, Massachusetts. Every figure on this page comes straight from federal CMS records, with no proprietary rating applied.

Board certification likely (heuristic — not verified)

GUY KATZ, M.D. practices in an ABMS-board-eligible specialty and shows active CMS Medicare participation + 2 hospital affiliations — signals consistent with board-certified status. For verified board certification, see CertificationMatters.org (the official ABMS public lookup).

GUY KATZ, M.D. at a glance

Quality data not reported

NPI registry status

Active

Issued 04/18/2017

NPI 1285168187

Primary specialty

Rheumatology Physician

Mid-sized

6,181 US NPIs in this specialty

Medicare Part D claims

393 81% vs specialty avg

2023 prescription claims

Specialty avg: 2,054

Specialty distribution in Massachusetts

How Rheumatology Physician compares to other specialties among Massachusetts providers

Massachusetts providers

Rheumatology Physician share within Massachusetts

1. Rheumatology Physician42%2. Internal medicine21%3. Family medicine17%4. Surgical12%5. Pediatric8%
Rheumatology Physician share within Massachusetts

Specialty board-certification context

Estimated specialty board-certified rate — Rheumatology Physician (ABMS / AOA reference)

Quality data not reported
Est. board-certified rate
78%
Rheumatology Physician ABMS/AOA estimate

Est. board-certified rate (Rheumatology Physician) — ABMS / AOA estimate

0%100%78%
Est. board-certified rate (Rheumatology Physician) — ABMS / AOA estimate

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).

GUY KATZ, M.D. is a Rheumatology Physician provider practicing in BOSTON, Massachusetts, according to the CMS National Plan and Provider Enumeration System (NPPES). Credentials: M.D.. NPI: 1285168187. This profile includes practice location, specialty classification, and organizational affiliations from the CMS provider registry. Provider information is self-reported to CMS and updated monthly.

GUY KATZ, M.D. appears in the CMS NPPES registry as a Rheumatology Physician provider holding M.D. credentials at 55 FRUIT ST, BOSTON, MA, 02114, with a listed phone of (617) 726-7938. NPI 1285168187 was issued on 04/18/2017. Because NPPES data is self-reported by the provider and refreshed monthly, the address, phone, and specialty reflect what KATZ most recently submitted to CMS rather than a vetted directory listing, which is why patients should always confirm the practice is still at this location before scheduling.

Medicare Part D records for calendar year 2023 show 393 prescription claims written by this provider, covering 64 Medicare beneficiaries and totaling roughly $1.2 million in drug spend, split 43% brand-name and 57% generic by claim count. These figures capture only Medicare Part D — commercial insurance, Medicaid, and cash-pay prescriptions are not included, and any drug-beneficiary cell under 11 is suppressed by CMS for patient privacy.

Rheumatology Physician is a mid-sized specialty nationwide, with 6,181 enrolled providers across 52 states and an average of 2,054 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

55 FRUIT ST
BOSTON, MA 02114

Provider Details

NPI 1285168187
Specialty Rheumatology Physician
Credentials M.D.
Gender Male
NPI Issued 04/18/2017

Hospital and facility affiliations

Facilities where GUY KATZ, M.D. bills Medicare from. Star ratings (1-5) are CMS Hospital Compare's "Hospital overall rating" — a composite of mortality, readmission, patient experience, safety, timely care, and efficient use of medical imaging measures. Source: CMS Care Compare.

MASSACHUSETTS GENERAL PHYSICIANS ORGANIZATION INC
BOSTON, MA
THE GENERAL HOSPITAL CORPORATION
BOSTON, MA

Affiliations sourced from CMS Doctors and Clinicians National Downloadable File; hospital ratings from CMS Hospital General Information dataset (cross-referenced by facility name + state).

Industry payments received (2024) — CMS Open Payments transparency data

The federal Physician Payments Sunshine Act (part of the Affordable Care Act) requires drug and medical-device manufacturers + group purchasing organizations to publicly report payments and other transfers of value to physicians and teaching hospitals. The data below covers 2024 for GUY KATZ, M.D.. Source: openpaymentsdata.cms.gov.

Total received

$3.8K

Largest payer

Amgen Inc.

Most common payment type

Consulting Fee

Industry payments are not necessarily indicators of bias — they include research funding, consulting fees for evidence-based work, royalties for inventions, food at conferences, and similar items. The disclosure exists for transparency. Read our methodology for how we interpret this data.

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 GUY KATZ, M.D.. To verify GUY KATZ, 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 · Above average

GUY KATZ, M.D. — brand share 43.0%
Specialty average (est.)

43% brand-name claims vs 57% generic, on 393 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.

393
Total Claims
$1.2M
Total Drug Cost
64
Medicare Beneficiaries

Prescribing Breakdown

30-Day Fills
652
Total Day Supply
18,998
Brand vs Generic
43% brand / 57% generic
Brand Drug Cost
$1.2M
Generic Drug Cost
$14K

Patient Demographics

Average Patient Age
73.0 years
Avg HCC Risk Score
1.98
Gender Split
59% female / 41% male
Age Distribution
<65: 11, 65-74: 22, 75-84: 20, 85+: 11

Top Prescribed Drugs (Medicare Part D)

Top drugs by claim count for calendar year 2023. Based on Medicare Part D data only.

Drug Claims
Prednisone
56
Allopurinol
28
Actemra
Tocilizumab
25
Enbrel Sureclick
Etanercept
22
Methotrexate
Methotrexate Sodium
22
Hydroxychloroquine Sulfate
19
Humira(Cf) Pen
Adalimumab
18
Leucovorin Calcium
16
Alendronate Sodium
15
Colchicine
15

* Counts below 11 are suppressed by CMS for patient privacy. Generic names shown where available from CMS Part D data.

Rheumatology Physician Overview

How GUY KATZ, M.D. fits within the Rheumatology Physician landscape nationally.

6,181
Rheumatology Physician Providers in US
52
States with Rheumatology Physician
2,054
Avg Claims per Provider

GUY KATZ, M.D.'s 393 claims are below the specialty average of 2,054.

Nearby Rheumatology Physician Providers in Massachusetts

Other clinicians with the same primary specialty enrolled in Massachusetts, drawn from the same CMS NPPES roster as KATZ.

Compare Rheumatology Physician nationally: see state-by-state distribution →

Frequently Asked Questions

What is GUY KATZ, M.D.'s specialty?
GUY KATZ, M.D. specializes in Rheumatology Physician and practices in BOSTON, Massachusetts. Credentials: M.D..
How much does GUY KATZ, M.D. prescribe under Medicare Part D?
In 2023, GUY KATZ, M.D. wrote 393 Medicare Part D claims totaling $1.2M in drug costs for 64 beneficiaries.
Where is GUY KATZ, M.D. located?
GUY KATZ, M.D. is located at 55 FRUIT ST, BOSTON, MA, 02114. Phone: (617) 726-7938.
What is GUY KATZ, M.D.'s NPI number?
GUY KATZ, M.D.'s National Provider Identifier (NPI) is 1285168187, issued on 04/18/2017.
Does GUY KATZ, M.D. prescribe more brand-name or generic drugs?
GUY KATZ, M.D.'s prescribing is 43% brand-name and 57% generic drugs by claim count, with $1.2M in brand drug costs.
How many Rheumatology Physician providers are there in the US?
There are 6,181 Rheumatology Physician providers across 52 states in the US. The average Rheumatology Physician provider writes 2,054 Medicare Part D claims per year.
What drugs does GUY KATZ, M.D. prescribe most often?
Based on 2023 Medicare Part D data, GUY KATZ, M.D.'s most frequently prescribed drugs include Prednisone, Allopurinol, Actemra. This reflects Medicare Part D prescriptions only and does not include commercial insurance or other payer types.
Does GUY KATZ, M.D. accept Medicare?
GUY KATZ, M.D. appears in CMS Medicare data with 393 Part D claims and 64 Medicare beneficiaries in 2023. Contact the provider's office directly to confirm current Medicare enrollment and accepted plans.
How can I verify GUY KATZ, M.D.'s credentials?
GUY KATZ, M.D.'s NPI is 1285168187 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

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