NPI registry status
Active
2026 NPPES data Nephrology Physician NPI 1649470683 MD
Verify on CMS → Maggie Chen, MD
Nephrology Physician in San Jose, California.
This profile is drawn from the federal National Provider Identifier Registry (CMS NPPES), which lists more than 7 million U.S. healthcare providers - including 10,569 in Nephrology 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
4K
Medicare Part D claims · 405 beneficiaries · Nephrology Physician avg: 1K
Generic prescribing
76%
generic claims · 23% brand-name · higher generic rates reduce patient out-of-pocket costs
MIPS score
99.6/100
▲ 17 pts above national avg 83.1 · Exceptional
Industry payments
$1.1K
46 payments · CMS Open Payments (Sunshine Act)
Source: CMS Medicare Part D Prescriber Public Use File, 2023
Compiled from official public sources by the PlainDoctor editorial team.
What the federal data shows
Maggie Chen, MD reported a CMS MIPS final score of 99.6/100 - above the 83.1 national average - and filed 4,379 Medicare Part D claims in 2023.
- 99.6/100
- MIPS score · +17 vs avg
- 4K
- Part D claims, 2023
- 76%
- 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.
Maggie Chen, MD's MIPS score vs every scored U.S. clinician
CMS Merit-based Incentive Payment System (MIPS) final score, 2023, the federal quality measure
100 Top 9% higher than 91% of 477,587 scored providers
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
Where Maggie Chen, MD sits
This provider among nephrology physician peers
Across the 2,476 nephrology physician providers who report both Medicare Part D prescribing and a MIPS quality score, Maggie Chen, MD writes more Part D claims than 93% of them and scores higher on MIPS quality than 93% - placing this provider in the high-volume, high-quality quadrant. Volume reflects patient-panel size and specialty, not quality; the two axes are independent.
Part D claim volume vs MIPS quality, by specialty percentile
Each dot is one nephrology physician peer from a representative sample of 60; the gold marker is Maggie Chen, MD. Source: CMS Medicare Part D Prescriber data and the CMS Merit-based Incentive Payment System, 2023.
✓
Board certification likely (heuristic, not verified)
Maggie Chen, MD practices in an ABMS-board-eligible specialty and shows active CMS Medicare participation + MIPS quality reporting - 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 Maggie Chen, MD?
High performer (top quartile)Primary specialty
Nephrology Physician
Medicare Part D claims
4,379 201% vs specialty avg
MIPS final score
99.6/100 16.5 pts vs avg
Specialty distribution in California
How Nephrology Physician compares to other specialties among California providers
Medicare quality performance, MIPS
Maggie Chen, MD's 2023 MIPS final score plotted against the Nephrology Physician national average
- MIPS Final Score
- 99.6/100
- vs 83.1 national avg · 2023 performance year
MIPS final score (Nephrology Physician) - 99.6/100 vs national avg 83.1
How MIPS and board certification work
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).
Maggie Chen, MD appears in the CMS NPPES registry as a Nephrology Physician provider holding MD credentials at 2360 MCKEE RD, San Jose, CA, 95116, with a listed phone of (408) 729-7128. NPI 1649470683 was issued on 07/18/2007.
Medicare Part D records for calendar year 2023 show 4,379 prescription claims written by this provider, covering 405 Medicare beneficiaries and totaling roughly $1.2 million in drug spend, split 23% brand-name and 76% generic by claim count. On the CMS Merit-based Incentive Payment System, this provider earned a Final Score of 99.6/100 for the 2023 performance year (Quality 82.9, Cost 90.8), compared with the national average of 83.1.
Nephrology Physician is a mid-sized specialty nationwide, with 10,569 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
Provider Details
| NPI | 1649470683 |
|---|---|
| Specialty | Nephrology Physician |
| Credentials | MD |
| Gender | Female |
| NPI Issued | 07/18/2007 |
CMS Quality Score (MIPS)
Merit-based Incentive Payment System (MIPS) scores from CMS, 2023 performance year.
99.6191
Final Score
Avg: 83.1
82.8832
Quality
90.847
Cost
90
Promoting Interoperability
Reporting: Individual
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 Maggie Chen, MD. Source: openpaymentsdata.cms.gov.
Total received
$1.1K
Largest payer
Ardelyx, 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 Maggie Chen, MD. To verify Maggie 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
Maggie Chen, MD - brand share 23.0%
Nephrology Physician average
23% brand-name claims vs 76% generic, on 4,379 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.
4,379
Total Claims
$1.2M
Total Drug Cost
405
Medicare Beneficiaries
Prescribing Breakdown
- 30-Day Fills
- 10,487
- Total Day Supply
- 309,749
- Brand vs Generic
- 23% brand / 76% generic
- Brand Drug Cost
- $1.1M
- Generic Drug Cost
- $144K
- Antibiotic Claims
- 23
Patient Demographics
- Average Patient Age
- 77.6 years
- Avg HCC Risk Score
- 2.73
- Gender Split
- 51% female / 49% male
- Age Distribution
- <65: 29, 65-74: 123, 75-84: 154, 85+: 99
Top Prescribed Drugs (Medicare Part D)
Top drugs by claim count for calendar year 2023. Based on Medicare Part D data only.
What Maggie Chen, MD prescribes most
Top Medicare Part D drugs by claim count, 2023
- Losartan Potassium
Losartan Potassium
416 claims
- Amlodipine Besylate
Amlodipine Besylate
341 claims
- Allopurinol
Allopurinol
276 claims
- Farxiga
Farxiga
224 claims
- Atorvastatin Calcium 135
Atorvastatin Calcium
135 claims
- Metformin Hcl 122
Metformin Hcl
122 claims
- Furosemide 118
Furosemide
118 claims
- Lisinopril 112
Lisinopril
112 claims
| Drug | Claims |
|---|---|
| Losartan Potassium | 416 |
| Amlodipine Besylate | 341 |
| Allopurinol | 276 |
| Farxiga Dapagliflozin Propanediol | 224 |
| Atorvastatin Calcium | 135 |
| Metformin Hcl | 122 |
| Furosemide | 118 |
| Lisinopril | 112 |
| Tamsulosin Hcl | 105 |
| Simvastatin | 103 |
* Counts below 11 are suppressed by CMS for patient privacy. Generic names shown where available from CMS Part D data.
Nephrology Physician Overview
How Maggie Chen, MD fits within the Nephrology Physician landscape nationally.
10,569
Nephrology Physician Providers in US
55
States with Nephrology Physician
1,454
Avg Claims per Provider
Maggie Chen, MD's 4,379 claims are above 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.
Dr. Antoine Abcar
MD
Los Angeles, CA
Dr. Basmah Abdalla
M.D.
Los Angeles, CA
Dr. Omaran Abdeen
M.D.
Mission Hills, CA
Dr. Anas Abou-Ismail
MD
Palm Springs, CA
Dr. Sreedhar Adapa
M.D.
Visalia, CA
Compare Nephrology 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 California medical board, federal registration is not a license check. Credential verification guide
- Weigh a second option: compare this provider with a nearby Nephrology 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.
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Frequently Asked Questions
What is Maggie Chen, MD's specialty? ▼
Maggie Chen, MD specializes in Nephrology Physician and practices in San Jose, California. Credentials: MD.
How much does Maggie Chen, MD prescribe under Medicare Part D? ▼
In 2023, Maggie Chen, MD wrote 4,379 Medicare Part D claims totaling $1.2M in drug costs for 405 beneficiaries.
What is Maggie Chen, MD's Medicare quality score? ▼
Maggie Chen, MD has a CMS MIPS Final Score of 99.6/100 (Quality: 82.9, Cost: 90.8). The national average MIPS Final Score is 83.1. Source: CMS Merit-based Incentive Payment System (MIPS) 2023.
Where is Maggie Chen, MD located? ▼
Maggie Chen, MD is located at 2360 MCKEE RD, San Jose, CA, 95116. Phone: (408) 729-7128.
What is Maggie Chen, MD's NPI number? ▼
Maggie Chen, MD's National Provider Identifier (NPI) is 1649470683, issued on 07/18/2007.
Does Maggie Chen, MD prescribe more brand-name or generic drugs? ▼
Maggie Chen, MD's prescribing is 23% brand-name and 76% generic drugs by claim count, with $1.1M in brand drug costs.
How many Nephrology Physician providers are there in the US? ▼
There are 10,569 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 Maggie Chen, MD prescribe most often? ▼
Based on 2023 Medicare Part D data, Maggie Chen, MD's most frequently prescribed drugs include Losartan Potassium, Amlodipine Besylate, Allopurinol. This reflects Medicare Part D prescriptions only and does not include commercial insurance or other payer types.
Does Maggie Chen, MD accept Medicare? ▼
Maggie Chen, MD appears in CMS Medicare data with 4,379 Part D claims and 405 Medicare beneficiaries in 2023. Contact the provider's office directly to confirm current Medicare enrollment and accepted plans.
How can I verify Maggie Chen, MD's credentials? ▼
Maggie Chen, MD's NPI is 1649470683 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
View source datasets and methodology notes
- 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
Compiled from official public sources by the PlainDoctor editorial team.
Every figure on PlainDoctor is rendered directly from the federal CMS NPPES registry, Medicare Part D, MIPS, and Open Payments records, no number is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of May 2026.