2026 NPPES data Endocrinology, Diabetes & Metabolism Physician NPI 1659574309 MD
Verify on CMS →

KAREN KNUDSEN, MD

Endocrinology, Diabetes & Metabolism Physician in WILLIAMSBURG, Virginia. 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
1K
Medicare Part D claims · 292 beneficiaries · Endocrinology, Diabetes & Metabolism Physician avg: 3K
Generic prescribing
49%
generic claims · 51% brand-name · higher generic rates reduce patient out-of-pocket costs
Industry payments
$687.89
25 payments · CMS Open Payments (Sunshine Act)

What the federal data shows

KAREN KNUDSEN, MD filed 1,289 Medicare Part D claims in 2023 as a Endocrinology, Diabetes & Metabolism Physician in WILLIAMSBURG, Virginia, prescribing 49% generic.

1K
Part D claims, 2023
49%
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.

KAREN KNUDSEN, MD's Medicare Part D volume vs every U.S. prescriber

Total Medicare Part D claims, 2023 — across all CMS prescribers nationally

1,289 Top 22% higher than 78% of 1,370,886 prescribers

0–200: 670,926 prescribers (49%). Below this entry. 200–400: 182,923 prescribers (13%). Below this entry. 400–600: 90,619 prescribers (7%). Below this entry. 600–800: 56,224 prescribers (4%). Below this entry. 800–1,000: 40,919 prescribers (3%). Below this entry. 1,000–1,200: 31,827 prescribers (2%). Below this entry. 1,200–1,400: 26,224 prescribers (2%). This entry sits in this band. 1,400–1,600: 21,710 prescribers (2%). Above this entry. 1,600–1,800: 19,072 prescribers (1%). Above this entry. 1,800–2,000: 16,451 prescribers (1%). Above this entry. 2,000–2,200: 213,991 prescribers (16%). Above this entry. This provider 0 2K+ every Part D prescriber (claims/yr), bucketed by value

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 certification likely (heuristic — not verified)

KAREN KNUDSEN, MD practices in an ABMS-board-eligible specialty and shows active CMS Medicare participation + 1 hospital affiliation — 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 KAREN KNUDSEN, MD?

Quality data not reported

NPI registry status

Active

Issued 06/08/2007

NPI 1659574309

Primary specialty

Endocrinology, Diabetes & Metabolism Physician

Mid-sized

7,852 US NPIs in this specialty

Medicare Part D claims

1,289 51% vs specialty avg

2023 prescription claims

Specialty avg: 2,639

Specialty distribution in Virginia

How Endocrinology, Diabetes & Metabolism Physician compares to other specialties among Virginia providers

Virginia providers

Endocrinology, Diabetes & Metabolism Physician share within Virginia

1. Endocrinology, Diabetes & Metabolism Physician42%2. Internal medicine21%3. Family medicine17%4. Surgical12%5. Pediatric8%
Endocrinology, Diabetes & Metabolism Physician share within Virginia

Specialty board-certification context

Estimated specialty board-certified rate — Endocrinology, Diabetes & Metabolism Physician (ABMS / AOA reference)

Quality data not reported
Est. board-certified rate
78%
Endocrinology, Diabetes & Metabolism Physician ABMS/AOA estimate

Est. board-certified rate (Endocrinology, Diabetes & Metabolism Physician) — ABMS / AOA estimate

0%100%78%
Est. board-certified rate (Endocrinology, Diabetes & Metabolism 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).

KAREN KNUDSEN, MD appears in the CMS NPPES registry as a Endocrinology, Diabetes & Metabolism Physician provider holding MD credentials at 5424 DISCOVERY PARK BOULEVARD, WILLIAMSBURG, VA, 23188, with a listed phone of (757) 903-4808. NPI 1659574309 was issued on 06/08/2007. Because NPPES data is self-reported by the provider and refreshed monthly, the address, phone, and specialty reflect what KNUDSEN 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 1,289 prescription claims written by this provider, covering 292 Medicare beneficiaries and totaling roughly $650K in drug spend, split 51% brand-name and 49% 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.

Endocrinology, Diabetes & Metabolism Physician is a mid-sized specialty nationwide, with 7,852 enrolled providers across 54 states and an average of 2,639 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

5424 DISCOVERY PARK BOULEVARD
WILLIAMSBURG, VA 23188

Provider Details

NPI 1659574309
Specialty Endocrinology, Diabetes & Metabolism Physician
Credentials MD
Gender Female
NPI Issued 06/08/2007

Hospital and facility affiliations

Facilities where KAREN KNUDSEN, MD 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.

TIDEWATER PHYSICIANS MULTISPECIALTY GROUP PC
NEWPORT NEWS, VA

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 KAREN KNUDSEN, MD. Source: openpaymentsdata.cms.gov.

Total received

$688

Largest payer

Insulet Corporation

Most common payment type

Food and Beverage

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.

Brand vs generic prescribing mix · Brand-heavy

KAREN KNUDSEN, MD — brand share 51.0%
Specialty average (est.)

51% brand-name claims vs 49% generic, on 1,289 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.

1,289
Total Claims
$650K
Total Drug Cost
292
Medicare Beneficiaries

Prescribing Breakdown

30-Day Fills
3,236
Total Day Supply
96,503
Brand vs Generic
51% brand / 49% generic
Brand Drug Cost
$591K
Generic Drug Cost
$15K

Patient Demographics

Average Patient Age
70.3 years
Avg HCC Risk Score
1.02
Gender Split
75% female / 25% male

Top Prescribed Drugs (Medicare Part D)

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

What KAREN KNUDSEN, MD 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
Levothyroxine Sodium
256
Synthroid
Levothyroxine Sodium
167
Methimazole
84
Metformin Hcl Er
Metformin Hcl
55
Trulicity
Dulaglutide
48
Ozempic
Semaglutide
32
Metformin Hcl
30
Humalog
Insulin Lispro
24
Liothyronine Sodium
20
Novolog Flexpen
Insulin Aspart
20

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

Endocrinology, Diabetes & Metabolism Physician Overview

How KAREN KNUDSEN, MD fits within the Endocrinology, Diabetes & Metabolism Physician landscape nationally.

7,852
Endocrinology, Diabetes & Metabolism Physician Providers in US
54
States with Endocrinology, Diabetes & Metabolism Physician
2,639
Avg Claims per Provider

KAREN KNUDSEN, MD's 1,289 claims are below the specialty average of 2,639.

Nearby Endocrinology, Diabetes & Metabolism Physician Providers in Virginia

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

Compare Endocrinology, Diabetes & Metabolism Physician nationally: see state-by-state distribution →

Frequently Asked Questions

What is KAREN KNUDSEN, MD's specialty?
KAREN KNUDSEN, MD specializes in Endocrinology, Diabetes & Metabolism Physician and practices in WILLIAMSBURG, Virginia. Credentials: MD.
How much does KAREN KNUDSEN, MD prescribe under Medicare Part D?
In 2023, KAREN KNUDSEN, MD wrote 1,289 Medicare Part D claims totaling $650K in drug costs for 292 beneficiaries.
Where is KAREN KNUDSEN, MD located?
KAREN KNUDSEN, MD is located at 5424 DISCOVERY PARK BOULEVARD, WILLIAMSBURG, VA, 23188. Phone: (757) 903-4808.
What is KAREN KNUDSEN, MD's NPI number?
KAREN KNUDSEN, MD's National Provider Identifier (NPI) is 1659574309, issued on 06/08/2007.
Does KAREN KNUDSEN, MD prescribe more brand-name or generic drugs?
KAREN KNUDSEN, MD's prescribing is 51% brand-name and 49% generic drugs by claim count, with $591K in brand drug costs.
How many Endocrinology, Diabetes & Metabolism Physician providers are there in the US?
There are 7,852 Endocrinology, Diabetes & Metabolism Physician providers across 54 states in the US. The average Endocrinology, Diabetes & Metabolism Physician provider writes 2,639 Medicare Part D claims per year.
What drugs does KAREN KNUDSEN, MD prescribe most often?
Based on 2023 Medicare Part D data, KAREN KNUDSEN, MD's most frequently prescribed drugs include Levothyroxine Sodium, Synthroid, Methimazole. This reflects Medicare Part D prescriptions only and does not include commercial insurance or other payer types.
Does KAREN KNUDSEN, MD accept Medicare?
KAREN KNUDSEN, MD appears in CMS Medicare data with 1,289 Part D claims and 292 Medicare beneficiaries in 2023. Contact the provider's office directly to confirm current Medicare enrollment and accepted plans.
How can I verify KAREN KNUDSEN, MD's credentials?
KAREN KNUDSEN, MD's NPI is 1659574309 with credentials MD. 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