2026 NPPES data Nephrology Physician NPI 1861499550 MD
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GREGORY KOZENY, MD

Nephrology Physician in WINFIELD, Illinois. 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 · 219 beneficiaries · Nephrology Physician avg: 1K
Industry payments
$69.56
3 payments · CMS Open Payments (Sunshine Act)
What the federal data reveals: GREGORY KOZENY, MD is a Nephrology Physician ([object Object]) practicing in WINFIELD, Illinois with a Medicare Part D prescribing footprint of 1K claims across 219 beneficiaries . Industry payments of $69.56 across 3 transactions are disclosed under CMS Open Payments (Sunshine Act).

What stands out: GREGORY KOZENY, MD filed 1,267 Medicare Part D claims in 2023 across WINFIELD, Illinois. Every figure on this page comes straight from federal CMS records, with no proprietary rating applied.

Board-eligible specialty (heuristic — not verified)

GREGORY KOZENY, MD practices in an ABMS-board-eligible specialty but we don't have enough CMS-participation signals to confirm active board-certified status. Consult CertificationMatters.org (the official ABMS public lookup).

GREGORY KOZENY, MD at a glance

Quality data not reported

NPI registry status

Active

Issued 07/07/2005

NPI 1861499550

Primary specialty

Nephrology Physician

Mid-sized

10,534 US NPIs in this specialty

Medicare Part D claims

1,267 13% vs specialty avg

2023 prescription claims

Specialty avg: 1,454

Specialty distribution in Illinois

How Nephrology Physician compares to other specialties among Illinois providers

Illinois providers

Nephrology Physician share within Illinois

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

Specialty board-certification context

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

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

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

0%100%78%
Est. board-certified rate (Nephrology 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).

GREGORY KOZENY, MD is a Nephrology Physician provider practicing in WINFIELD, Illinois, according to the CMS National Plan and Provider Enumeration System (NPPES). Credentials: MD. NPI: 1861499550. 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.

GREGORY KOZENY, MD appears in the CMS NPPES registry as a Nephrology Physician provider holding MD credentials at 25 N WINFIELD RD STE 414, WINFIELD, IL, 60190, with a listed phone of (630) 690-1220. NPI 1861499550 was issued on 07/07/2005. Because NPPES data is self-reported by the provider and refreshed monthly, the address, phone, and specialty reflect what KOZENY 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 1,267 prescription claims written by this provider, covering 219 Medicare beneficiaries and totaling roughly $257K in drug spend. 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.

Nephrology Physician is a mid-sized specialty nationwide, with 10,534 enrolled providers across 55 states and an average of 1,454 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

25 N WINFIELD RD STE 414
WINFIELD, IL 60190

Provider Details

NPI 1861499550
Specialty Nephrology Physician
Credentials MD
Gender Male
NPI Issued 07/07/2005

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 GREGORY KOZENY, MD. Source: openpaymentsdata.cms.gov.

Total received

$70

Largest payer

Vifor Pharma, 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.

License & disciplinary context — Illinois IDFPR 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 ~42K Illinois medical licensees in 2023 — they are NOT specific to GREGORY KOZENY, MD. To verify GREGORY KOZENY, MD's current license status, search the IDFPR public license lookup directly, or check the Federation of State Medical Boards (FSMB) verification service.

106
Total board actions, Illinois 2023
Across 103 cases
2.52
Actions per 1,000 licensees
Illinois statewide rate
probation
Most common action type
38 cases

IDFPR 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 Illinois 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 2023.

1,267
Total Claims
$257K
Total Drug Cost
219
Medicare Beneficiaries

Prescribing Breakdown

30-Day Fills
2,806
Total Day Supply
83,061
Generic Drug Cost
$50K
Antibiotic Claims
15

Patient Demographics

Average Patient Age
73.5 years
Avg HCC Risk Score
3.10
Gender Split
44% female / 56% male
Age Distribution
<65: 25, 65-74: 79, 75-84: 91, 85+: 24

Top Prescribed Drugs (Medicare Part D)

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

Drug Claims
Losartan Potassium
81
Farxiga
Dapagliflozin Propanediol
67
Amlodipine Besylate
64
Furosemide
60
Bumetanide
57
Carvedilol
53
Spironolactone
46
Prednisone
45
Sevelamer Carbonate
42
Lisinopril
37

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

Nephrology Physician Overview

How GREGORY KOZENY, MD fits within the Nephrology Physician landscape nationally.

10,534
Nephrology Physician Providers in US
55
States with Nephrology Physician
1,454
Avg Claims per Provider

GREGORY KOZENY, MD's 1,267 claims are below the specialty average of 1,454.

Nearby Nephrology Physician Providers in Illinois

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

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

Frequently Asked Questions

What is GREGORY KOZENY, MD's specialty?
GREGORY KOZENY, MD specializes in Nephrology Physician and practices in WINFIELD, Illinois. Credentials: MD.
How much does GREGORY KOZENY, MD prescribe under Medicare Part D?
In 2023, GREGORY KOZENY, MD wrote 1,267 Medicare Part D claims totaling $257K in drug costs for 219 beneficiaries.
Where is GREGORY KOZENY, MD located?
GREGORY KOZENY, MD is located at 25 N WINFIELD RD STE 414, WINFIELD, IL, 60190. Phone: (630) 690-1220.
What is GREGORY KOZENY, MD's NPI number?
GREGORY KOZENY, MD's National Provider Identifier (NPI) is 1861499550, issued on 07/07/2005.
How many Nephrology Physician providers are there in the US?
There are 10,534 Nephrology Physician providers across 55 states in the US. The average Nephrology Physician provider writes 1,454 Medicare Part D claims per year.
What drugs does GREGORY KOZENY, MD prescribe most often?
Based on 2023 Medicare Part D data, GREGORY KOZENY, MD's most frequently prescribed drugs include Losartan Potassium, Farxiga, Amlodipine Besylate. This reflects Medicare Part D prescriptions only and does not include commercial insurance or other payer types.
Does GREGORY KOZENY, MD accept Medicare?
GREGORY KOZENY, MD appears in CMS Medicare data with 1,267 Part D claims and 219 Medicare beneficiaries in 2023. Contact the provider's office directly to confirm current Medicare enrollment and accepted plans.
How can I verify GREGORY KOZENY, MD's credentials?
GREGORY KOZENY, MD's NPI is 1861499550 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