2026 NPPES data Internal Medicine Physician NPI 1255728978 MD
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Kelley Williams, MD

Internal Medicine Physician in Saint Louis, Missouri. 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
2K
Medicare Part D claims · 257 beneficiaries · Internal Medicine Physician avg: 3K
Generic prescribing
47%
generic claims · 53% brand-name · higher generic rates reduce patient out-of-pocket costs
MIPS score
79.3/100
▼ 4 pts below national avg 83.1 · [object Object]
Industry payments
$18.55
1 payments · CMS Open Payments (Sunshine Act)

What the federal data shows

Kelley Williams, MD reported a CMS MIPS final score of 79.3/100 — below the 83.1 national average — and filed 2,484 Medicare Part D claims in 2023.

79.3/100
MIPS score · -4 vs avg
2K
Part D claims, 2023
47%
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.

Kelley Williams, MD's MIPS score vs every scored U.S. clinician

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

79 30th percentile higher than 30% 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)

Kelley Williams, MD practices in an ABMS-board-eligible specialty and shows active CMS Medicare participation + MIPS quality reporting + 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 Kelley Williams, MD?

Near national average

NPI registry status

Active

Issued 04/21/2015

NPI 1255728978

Primary specialty

Internal Medicine Physician

High-volume

172,858 US NPIs in this specialty

Medicare Part D claims

2,484 9% vs specialty avg

2023 prescription claims

Specialty avg: 2,716

MIPS final score

79.3/100 3.8 pts vs avg

Above neutral band

vs 83.1 national avg

Specialty distribution in Missouri

How Internal Medicine Physician compares to other specialties among Missouri providers

Missouri providers

Internal Medicine Physician share within Missouri

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

Medicare quality performance — MIPS

Kelley Williams, MD's 2023 MIPS final score plotted against the Internal Medicine Physician national average

Near national average
MIPS Final Score
79.3/100
vs 83.1 national avg · 2023 performance year

MIPS final score (Internal Medicine Physician) — 79.3/100 vs national avg 83.1

0%100%National avg83%79.3%
MIPS final score (Internal Medicine Physician) — 79.3/100 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).

Kelley Williams, MD appears in the CMS NPPES registry as a Internal Medicine Physician provider holding MD credentials at 4921 PARKVIEW PL, Saint Louis, MO, 63110, with a listed phone of (314) 362-3500. NPI 1255728978 was issued on 04/21/2015. Because NPPES data is self-reported by the provider and refreshed monthly, the address, phone, and specialty reflect what Williams 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 2,484 prescription claims written by this provider, covering 257 Medicare beneficiaries and totaling roughly $1.7 million in drug spend, split 53% brand-name and 47% 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 79.3/100 for the 2023 performance year (Quality 71.5, Cost 59.5), 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

4921 PARKVIEW PL
Saint Louis, MO 63110

Provider Details

NPI 1255728978
Specialty Internal Medicine Physician
Credentials MD
Gender Female
NPI Issued 04/21/2015

CMS Quality Score (MIPS)

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

79.292
Final Score
Avg: 83.1
71.46
Quality
59.5132
Cost
100
Promoting Interoperability

Reporting: Group practice

Hospital and facility affiliations

Facilities where Kelley Williams, 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.

Washington University
Saint Louis, MO

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 Kelley Williams, MD. Source: openpaymentsdata.cms.gov.

Total received

$19

Largest payer

Novo Nordisk Inc

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

Kelley Williams, MD — brand share 53.0%
Specialty average (est.)

53% brand-name claims vs 47% generic, on 2,484 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.

2,484
Total Claims
$1.7M
Total Drug Cost
257
Medicare Beneficiaries

Prescribing Breakdown

30-Day Fills
4,825
Total Day Supply
141,913
Brand vs Generic
53% brand / 47% generic
Brand Drug Cost
$1.5M
Generic Drug Cost
$39K

Patient Demographics

Average Patient Age
64.9 years
Avg HCC Risk Score
1.89
Gender Split
57% female / 43% male
Age Distribution
<65: 82, 65-74: 114, 75-84: 49, 85+: 12

Top Prescribed Drugs (Medicare Part D)

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

What Kelley Williams, 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
Ozempic
Semaglutide
205
Levothyroxine Sodium
151
Trulicity
Dulaglutide
124
Metformin Hcl Er
Metformin Hcl
94
Metformin Hcl
93
Jardiance
Empagliflozin
91
Humalog
Insulin Lispro
84
Atorvastatin Calcium
71
Humalog Kwikpen U-100
Insulin Lispro
68
Mounjaro
Tirzepatide
64

* 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 Kelley Williams, MD 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

Kelley Williams, MD's 2,484 claims are below the specialty average of 2,716.

Nearby Internal Medicine Physician Providers in Missouri

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

Compare Internal Medicine Physician 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 Missouri medical board — federal registration is not a license check. Credential verification guide
  • Weigh a second option: compare this provider with a nearby Internal Medicine Physician 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.

Frequently Asked Questions

What is Kelley Williams, MD's specialty?
Kelley Williams, MD specializes in Internal Medicine Physician and practices in Saint Louis, Missouri. Credentials: MD.
How much does Kelley Williams, MD prescribe under Medicare Part D?
In 2023, Kelley Williams, MD wrote 2,484 Medicare Part D claims totaling $1.7M in drug costs for 257 beneficiaries.
What is Kelley Williams, MD's Medicare quality score?
Kelley Williams, MD has a CMS MIPS Final Score of 79.3/100 (Quality: 71.5, Cost: 59.5). The national average MIPS Final Score is 83.1. Source: CMS Merit-based Incentive Payment System (MIPS) 2023.
Where is Kelley Williams, MD located?
Kelley Williams, MD is located at 4921 PARKVIEW PL, Saint Louis, MO, 63110. Phone: (314) 362-3500.
What is Kelley Williams, MD's NPI number?
Kelley Williams, MD's National Provider Identifier (NPI) is 1255728978, issued on 04/21/2015.
Does Kelley Williams, MD prescribe more brand-name or generic drugs?
Kelley Williams, MD's prescribing is 53% brand-name and 47% generic drugs by claim count, with $1.5M 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 Kelley Williams, MD prescribe most often?
Based on 2023 Medicare Part D data, Kelley Williams, MD's most frequently prescribed drugs include Ozempic, Levothyroxine Sodium, Trulicity. This reflects Medicare Part D prescriptions only and does not include commercial insurance or other payer types.
Does Kelley Williams, MD accept Medicare?
Kelley Williams, MD appears in CMS Medicare data with 2,484 Part D claims and 257 Medicare beneficiaries in 2023. Contact the provider's office directly to confirm current Medicare enrollment and accepted plans.
How can I verify Kelley Williams, MD's credentials?
Kelley Williams, MD's NPI is 1255728978 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.
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