2026 NPPES data Nephrology Physician NPI 1881772887 MD
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MAY CHEN, MD

Nephrology Physician in MISSION VIEJO, California. 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 · 170 beneficiaries · Nephrology Physician avg: 1K
Generic prescribing
88%
generic claims · 12% brand-name · higher generic rates reduce patient out-of-pocket costs
Industry payments
$980.97
42 payments · CMS Open Payments (Sunshine Act)
What the federal data reveals: MAY CHEN, MD is a Nephrology Physician ([object Object]) practicing in MISSION VIEJO, California with a Medicare Part D prescribing footprint of 1K claims across 170 beneficiaries — 12% brand-name prescribing . Industry payments of $980.97 across 42 transactions are disclosed under CMS Open Payments (Sunshine Act).

What stands out: MAY CHEN, MD filed 1,372 Medicare Part D claims in 2023 across MISSION VIEJO, California. Every figure on this page comes straight from federal CMS records, with no proprietary rating applied.

Board certification likely (heuristic — not verified)

MAY CHEN, 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).

MAY CHEN, MD at a glance

Quality data not reported

NPI registry status

Active

Issued 11/01/2006

NPI 1881772887

Primary specialty

Nephrology Physician

Mid-sized

10,534 US NPIs in this specialty

Medicare Part D claims

1,372 6% vs specialty avg

2023 prescription claims

Specialty avg: 1,454

Specialty distribution in California

How Nephrology Physician compares to other specialties among California providers

California providers

Nephrology Physician share within California

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

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).

MAY CHEN, MD is a Nephrology Physician provider practicing in MISSION VIEJO, California, according to the CMS National Plan and Provider Enumeration System (NPPES). Credentials: MD. NPI: 1881772887. 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.

MAY CHEN, MD appears in the CMS NPPES registry as a Nephrology Physician provider holding MD credentials at 26800 CROWN VALLEY PKWY, MISSION VIEJO, CA, 92691, with a listed phone of (949) 364-0644. NPI 1881772887 was issued on 11/01/2006. 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 1,372 prescription claims written by this provider, covering 170 Medicare beneficiaries and totaling roughly $165K in drug spend, split 12% brand-name and 88% 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.

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

26800 CROWN VALLEY PKWY
MISSION VIEJO, CA 92691

Provider Details

NPI 1881772887
Specialty Nephrology Physician
Credentials MD
Gender Female
NPI Issued 11/01/2006

Hospital and facility affiliations

Facilities where MAY CHEN, 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.

PROVIDENCE MEDICAL FOUNDATION
FULLERTON, CA

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 MAY CHEN, MD. Source: openpaymentsdata.cms.gov.

Total received

$981

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 — California MBC 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 ~150K California medical licensees in 2023 — they are NOT specific to MAY CHEN, MD. To verify MAY CHEN, MD's current license status, search the MBC public license lookup directly, or check the Federation of State Medical Boards (FSMB) verification service.

576
Total board actions, California 2023
Across 556 cases
3.84
Actions per 1,000 licensees
California statewide rate
probation
Most common action type
186 cases

MBC 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 California disciplinary trends page. Cross-checked against FSMB U.S. Medical Regulatory Trends.

Brand vs generic prescribing mix · Typical

MAY CHEN, MD — brand share 12.0%
Specialty average (est.)

12% brand-name claims vs 88% generic, on 1,372 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.

1,372
Total Claims
$165K
Total Drug Cost
170
Medicare Beneficiaries

Prescribing Breakdown

30-Day Fills
2,823
Total Day Supply
82,829
Brand vs Generic
12% brand / 88% generic
Brand Drug Cost
$118K
Generic Drug Cost
$47K
Antibiotic Claims
41

Patient Demographics

Average Patient Age
74.6 years
Avg HCC Risk Score
3.50
Gender Split
49% female / 51% male
Age Distribution
<65: 17, 65-74: 64, 75-84: 58, 85+: 31

Top Prescribed Drugs (Medicare Part D)

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

Drug Claims
Amlodipine Besylate
91
Hydralazine Hcl
78
Furosemide
67
Losartan Potassium
63
Atorvastatin Calcium
57
Pantoprazole Sodium
50
Carvedilol
49
Potassium Chloride
40
Nifedipine Er
Nifedipine
38
Calcium Acetate
36

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

Nephrology Physician Overview

How MAY CHEN, 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

MAY CHEN, MD's 1,372 claims are below the specialty average of 1,454.

Nearby Nephrology Physician Providers in California

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

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

Frequently Asked Questions

What is MAY CHEN, MD's specialty?
MAY CHEN, MD specializes in Nephrology Physician and practices in MISSION VIEJO, California. Credentials: MD.
How much does MAY CHEN, MD prescribe under Medicare Part D?
In 2023, MAY CHEN, MD wrote 1,372 Medicare Part D claims totaling $165K in drug costs for 170 beneficiaries.
Where is MAY CHEN, MD located?
MAY CHEN, MD is located at 26800 CROWN VALLEY PKWY, MISSION VIEJO, CA, 92691. Phone: (949) 364-0644.
What is MAY CHEN, MD's NPI number?
MAY CHEN, MD's National Provider Identifier (NPI) is 1881772887, issued on 11/01/2006.
Does MAY CHEN, MD prescribe more brand-name or generic drugs?
MAY CHEN, MD's prescribing is 12% brand-name and 88% generic drugs by claim count, with $118K in brand drug costs.
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 MAY CHEN, MD prescribe most often?
Based on 2023 Medicare Part D data, MAY CHEN, MD's most frequently prescribed drugs include Amlodipine Besylate, Hydralazine Hcl, Furosemide. This reflects Medicare Part D prescriptions only and does not include commercial insurance or other payer types.
Does MAY CHEN, MD accept Medicare?
MAY CHEN, MD appears in CMS Medicare data with 1,372 Part D claims and 170 Medicare beneficiaries in 2023. Contact the provider's office directly to confirm current Medicare enrollment and accepted plans.
How can I verify MAY CHEN, MD's credentials?
MAY CHEN, MD's NPI is 1881772887 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