2026 NPPES data Internal Medicine Physician NPI 1255352167 M.D.
Verify on CMS →

DONNA PHANUMAS, M.D.

Internal Medicine Physician in GREENWICH, Connecticut. 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
344
Medicare Part D claims · 96 beneficiaries · Internal Medicine Physician avg: 3K
Generic prescribing
97%
generic claims · 3% brand-name · higher generic rates reduce patient out-of-pocket costs
MIPS score
70.2281/100
▼ 13 pts below national avg 83.1 · [object Object]

What the federal data shows

DONNA PHANUMAS, M.D. reported a CMS MIPS final score of 70.2281/100 — below the 83.1 national average — and filed 344 Medicare Part D claims in 2023.

70.2281/100
MIPS score · -13 vs avg
344
Part D claims, 2023
97%
generic prescribing
Likely
board-certified (heuristic)

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.

DONNA PHANUMAS, M.D.'s MIPS score vs every scored U.S. clinician

CMS Merit-based Incentive Payment System (MIPS) final score, 2023 — the federal quality measure

70 8th percentile higher than 8% of 477,587 scored providers

0–10: 8,684 scored providers (2%). Below this entry. 10–20: 3,008 scored providers (1%). Below this entry. 20–30: 3,069 scored providers (1%). Below this entry. 30–40: 2,746 scored providers (1%). Below this entry. 40–50: 2,928 scored providers (1%). Below this entry. 50–60: 5,882 scored providers (1%). Below this entry. 60–70: 13,906 scored providers (3%). Below this entry. 70–80: 118,074 scored providers (25%). This entry sits in this band. 80–90: 129,887 scored providers (27%). Above this entry. 90–100: 189,403 scored providers (40%). Above this entry. This provider 0 100 every MIPS-scored clinician, bucketed by value

Each bar is a band; taller bars hold more scored providers. 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 Merit-based Incentive Payment System (MIPS) · 2023

Board certification likely (heuristic — not verified)

DONNA PHANUMAS, M.D. practices in an ABMS-board-eligible specialty and shows active CMS Medicare participation + MIPS quality reporting — signals consistent with board-certified status. For verified board certification, see CertificationMatters.org (the official ABMS public lookup).

What does the federal data show about DONNA PHANUMAS, M.D.?

Below national average

NPI registry status

Active

Issued 07/23/2006

NPI 1255352167

Primary specialty

Internal Medicine Physician

High-volume

172,858 US NPIs in this specialty

Medicare Part D claims

344 87% vs specialty avg

2023 prescription claims

Specialty avg: 2,716

MIPS final score

70.2281/100 12.871899999999997% pts

Mid-tier band

vs 83.1 national avg

Specialty distribution in Connecticut

How Internal Medicine Physician compares to other specialties among Connecticut providers

Connecticut providers

Internal Medicine Physician share within Connecticut

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

Medicare quality performance — MIPS

DONNA PHANUMAS, M.D.'s 2023 MIPS final score plotted against the Internal Medicine Physician national average

Below national average
MIPS Final Score
70.2281/100
vs 83.1 national avg · 2023 performance year

MIPS final score (Internal Medicine Physician) — 70.2281/100 vs national avg 83.1

0%100%National avg83%70.2%
MIPS final score (Internal Medicine Physician) — 70.2281/100 vs national avg 83.1

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).

DONNA PHANUMAS, M.D. appears in the CMS NPPES registry as a Internal Medicine Physician provider holding M.D. credentials at 5 PERRYRIDGE RD, GREENWICH, CT, 06830, with a listed phone of (203) 863-4376. NPI 1255352167 was issued on 07/23/2006. Because NPPES data is self-reported by the provider and refreshed monthly, the address, phone, and specialty reflect what PHANUMAS 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 344 prescription claims written by this provider, covering 96 Medicare beneficiaries and totaling roughly $16K in drug spend, split 3% brand-name and 97% 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. On the CMS Merit-based Incentive Payment System, this provider earned a Final Score of 70.2281/100 for the 2023 performance year (Quality 94.4405, Cost 28.8198), compared with the national average of 83.1.

Internal Medicine Physician is a high-volume specialty nationwide, with 172,858 enrolled providers across 56 states and an average of 2,716 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

5 PERRYRIDGE RD
GREENWICH, CT 06830

Provider Details

NPI 1255352167
Specialty Internal Medicine Physician
Credentials M.D.
Gender Female
NPI Issued 07/23/2006

CMS Quality Score (MIPS)

Merit-based Incentive Payment System (MIPS) scores from CMS, 2023 performance year.

70.2281
Final Score
Avg: 83.1
94.4405
Quality
28.8198
Cost
73
Promoting Interoperability

Reporting: Group practice

Brand vs generic prescribing mix · Generic-heavy

DONNA PHANUMAS, M.D. — brand share 3.0%
Specialty average (est.)

3% brand-name claims vs 97% generic, on 344 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.

344
Total Claims
$16K
Total Drug Cost
96
Medicare Beneficiaries

Prescribing Breakdown

30-Day Fills
612
Total Day Supply
18,165
Brand vs Generic
3% brand / 97% generic
Brand Drug Cost
$5K
Generic Drug Cost
$10K

Patient Demographics

Average Patient Age
82.6 years
Avg HCC Risk Score
1.42
Gender Split
78% female / 22% male
Age Distribution
<65: 0, 65-74: 18, 75-84: 35, 85+: 43

Top Prescribed Drugs (Medicare Part D)

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

What DONNA PHANUMAS, M.D. prescribes most

Top Medicare Part D drugs by claim count, 2023

claims
Source CMS Medicare Part D Prescriber Public Use File As of 2023
Drug Claims
Donepezil Hcl
134
Memantine Hcl
60
Escitalopram Oxalate
18
Quetiapine Fumarate
18
Mirtazapine
14
Memantine Hcl Er
Memantine Hcl
12
Rivastigmine
Rivastigmine Tartrate
12
Sertraline Hcl
11

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

Internal Medicine Physician Overview

How DONNA PHANUMAS, M.D. fits within the Internal Medicine Physician landscape nationally.

172,858
Internal Medicine Physician Providers in US
56
States with Internal Medicine Physician
2,716
Avg Claims per Provider

DONNA PHANUMAS, M.D.'s 344 claims are below the specialty average of 2,716.

Nearby Internal Medicine Physician Providers in Connecticut

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

Compare Internal Medicine Physician nationally: see state-by-state distribution →

Frequently Asked Questions

What is DONNA PHANUMAS, M.D.'s specialty?
DONNA PHANUMAS, M.D. specializes in Internal Medicine Physician and practices in GREENWICH, Connecticut. Credentials: M.D..
How much does DONNA PHANUMAS, M.D. prescribe under Medicare Part D?
In 2023, DONNA PHANUMAS, M.D. wrote 344 Medicare Part D claims totaling $16K in drug costs for 96 beneficiaries.
What is DONNA PHANUMAS, M.D.'s Medicare quality score?
DONNA PHANUMAS, M.D. has a CMS MIPS Final Score of 70.2281/100 (Quality: 94.4405, Cost: 28.8198). The national average MIPS Final Score is 83.1. Source: CMS Merit-based Incentive Payment System (MIPS) 2023.
Where is DONNA PHANUMAS, M.D. located?
DONNA PHANUMAS, M.D. is located at 5 PERRYRIDGE RD, GREENWICH, CT, 06830. Phone: (203) 863-4376.
What is DONNA PHANUMAS, M.D.'s NPI number?
DONNA PHANUMAS, M.D.'s National Provider Identifier (NPI) is 1255352167, issued on 07/23/2006.
Does DONNA PHANUMAS, M.D. prescribe more brand-name or generic drugs?
DONNA PHANUMAS, M.D.'s prescribing is 3% brand-name and 97% generic drugs by claim count, with $5K in brand drug costs.
How many Internal Medicine Physician providers are there in the US?
There are 172,858 Internal Medicine Physician providers across 56 states in the US. The average Internal Medicine Physician provider writes 2,716 Medicare Part D claims per year.
What drugs does DONNA PHANUMAS, M.D. prescribe most often?
Based on 2023 Medicare Part D data, DONNA PHANUMAS, M.D.'s most frequently prescribed drugs include Donepezil Hcl, Memantine Hcl, Escitalopram Oxalate. This reflects Medicare Part D prescriptions only and does not include commercial insurance or other payer types.
Does DONNA PHANUMAS, M.D. accept Medicare?
DONNA PHANUMAS, M.D. appears in CMS Medicare data with 344 Part D claims and 96 Medicare beneficiaries in 2023. Contact the provider's office directly to confirm current Medicare enrollment and accepted plans.
How can I verify DONNA PHANUMAS, M.D.'s credentials?
DONNA PHANUMAS, M.D.'s NPI is 1255352167 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.
Quality Performance
CMS Merit-based Incentive Payment System (MIPS) — 2023 performance year.
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