2026 NPPES data Obstetrics & Gynecology Physician NPI 1023056355 M.D.
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Michael Chen, M.D.

Obstetrics & Gynecology Physician in O Fallon, Missouri. This profile is drawn from the federal National Provider Identifier Registry (CMS NPPES), which lists more than 7 million U.S. healthcare providers — including 44,313 in Obstetrics & Gynecology Physician, and covers specialty classification, practice address, and Medicare Part D prescribing data when reported. According to CMS, every field reflects the provider's official federal registration — see our methodology.

Federal data — no proprietary rating. We show these CMS records as-is — no composite score, no star rating, no editorial opinion layered on top.
Prescribing volume
63
Medicare Part D claims · 37 beneficiaries · Obstetrics & Gynecology Physician avg: 179
Industry payments
$21.34
1 payments · CMS Open Payments (Sunshine Act)
Compiled from official public sources by the PlainDoctor editorial team.

What the federal data shows

Michael Chen, M.D. filed 63 Medicare Part D claims in 2023 as a Obstetrics & Gynecology Physician in O Fallon, Missouri.

63
Part D claims, 2023
$21.34
industry payments (Sunshine Act)

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.

Michael Chen, M.D.'s Medicare Part D volume vs every U.S. prescriber

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

63 0th percentile higher than 0% of 1,370,886 prescribers

0–200: 670,926 prescribers (49%). This entry sits in this band. 200–400: 182,923 prescribers (13%). Above this entry. 400–600: 90,619 prescribers (7%). Above this entry. 600–800: 56,224 prescribers (4%). Above this entry. 800–1,000: 40,919 prescribers (3%). Above this entry. 1,000–1,200: 31,827 prescribers (2%). Above this entry. 1,200–1,400: 26,224 prescribers (2%). Above this entry. 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-eligible specialty (heuristic — not verified)

Michael Chen, M.D. 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).

What does the federal data show about Michael Chen, M.D.?

Quality data not reported

NPI registry status

Active

Issued 06/02/2006

NPI 1023056355

Primary specialty

Obstetrics & Gynecology Physician

Mid-sized

44,313 US NPIs in this specialty

Medicare Part D claims

63 65% vs specialty avg

2023 prescription claims

Specialty avg: 179

Specialty distribution in Missouri

How Obstetrics & Gynecology Physician compares to other specialties among Missouri providers

Missouri providers

Largest specialties in Missouri (% of in-state providers)

Pharmacist — 4.8%Pharmacist4.8%Professional Counselor — 4.8%Professional Counselor4.8%Speech-Language Pathologist — 4.5%Speech-Language Pathologist4.5%Clinical Social Worker — 4.5%Clinical Social Worker4.5%Family Nurse Practitioner — 4.3%Family Nurse Practitioner4.3%Physical Therapist — 4%Physical Therapist4%Obstetrics & Gynecology Physician — 0.8%Obstetrics & Gynecology Physician0.8%
Largest specialties in Missouri (% of in-state providers)

Specialty board-certification context

Estimated specialty board-certified rate — Obstetrics & Gynecology Physician (ABMS / AOA reference)

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

Est. board-certified rate (Obstetrics & Gynecology Physician) — ABMS / AOA estimate

0%100%78%
Est. board-certified rate (Obstetrics & Gynecology 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).

Michael Chen, M.D. appears in the CMS NPPES registry as a Obstetrics & Gynecology Physician provider holding M.D. credentials at 20 PROGRESS POINT PKWY, O Fallon, MO, 63368, with a listed phone of (636) 344-3105. NPI 1023056355 was issued on 06/02/2006. Because NPPES data is self-reported by the provider and refreshed monthly, the address, phone, and specialty reflect what Chen 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 63 prescription claims written by this provider, covering 37 Medicare beneficiaries and totaling roughly $6K 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.

Obstetrics & Gynecology Physician is a mid-sized specialty nationwide, with 44,313 enrolled providers across 56 states and an average of 179 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

20 PROGRESS POINT PKWY
O Fallon, MO 63368

Provider Details

NPI 1023056355
Specialty Obstetrics & Gynecology Physician
Credentials M.D.
Gender Male
NPI Issued 06/02/2006

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 Michael Chen, M.D.. Source: openpaymentsdata.cms.gov.

Total received

$21

Largest payer

Hologic Sales and Service, LLC

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.

Medicare Part D Prescribing Data

CMS Medicare Part D prescriber-level data for calendar year 2023.

63
Total Claims
$6K
Total Drug Cost
37
Medicare Beneficiaries

Prescribing Breakdown

30-Day Fills
131
Total Day Supply
3,586
Generic Drug Cost
$2K

Patient Demographics

Average Patient Age
69.9 years
Avg HCC Risk Score
0.91

Top Prescribed Drugs (Medicare Part D)

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

Drug Claims
Estradiol
11

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

Obstetrics & Gynecology Physician Overview

How Michael Chen, M.D. fits within the Obstetrics & Gynecology Physician landscape nationally.

44,313
Obstetrics & Gynecology Physician Providers in US
56
States with Obstetrics & Gynecology Physician
179
Avg Claims per Provider

Michael Chen, M.D.'s 63 claims are below the specialty average of 179.

Nearby Obstetrics & Gynecology Physician Providers in Missouri

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

Compare Obstetrics & Gynecology 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 Obstetrics & Gynecology 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 Michael Chen, M.D.'s specialty?
Michael Chen, M.D. specializes in Obstetrics & Gynecology Physician and practices in O Fallon, Missouri. Credentials: M.D..
How much does Michael Chen, M.D. prescribe under Medicare Part D?
In 2023, Michael Chen, M.D. wrote 63 Medicare Part D claims totaling $6K in drug costs for 37 beneficiaries.
Where is Michael Chen, M.D. located?
Michael Chen, M.D. is located at 20 PROGRESS POINT PKWY, O Fallon, MO, 63368. Phone: (636) 344-3105.
What is Michael Chen, M.D.'s NPI number?
Michael Chen, M.D.'s National Provider Identifier (NPI) is 1023056355, issued on 06/02/2006.
How many Obstetrics & Gynecology Physician providers are there in the US?
There are 44,313 Obstetrics & Gynecology Physician providers across 56 states in the US. The average Obstetrics & Gynecology Physician provider writes 179 Medicare Part D claims per year.
What drugs does Michael Chen, M.D. prescribe most often?
Based on 2023 Medicare Part D data, Michael Chen, M.D.'s most frequently prescribed drugs include Estradiol. This reflects Medicare Part D prescriptions only and does not include commercial insurance or other payer types.
Does Michael Chen, M.D. accept Medicare?
Michael Chen, M.D. appears in CMS Medicare data with 63 Part D claims and 37 Medicare beneficiaries in 2023. Contact the provider's office directly to confirm current Medicare enrollment and accepted plans.
How can I verify Michael Chen, M.D.'s credentials?
Michael Chen, M.D.'s NPI is 1023056355 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

Compiled from official public sources by the PlainDoctor editorial team.