2026 NPPES data Nephrology Physician NPI 1588036719 D.O.
Verify on CMS →

MICHAEL CHAU, D.O.

Nephrology Physician in SAN DIEGO, 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
858
Medicare Part D claims · 233 beneficiaries · Nephrology Physician avg: 1K
Industry payments
$328.57
3 payments · CMS Open Payments (Sunshine Act)
What the federal data reveals: MICHAEL CHAU, D.O. is a Nephrology Physician ([object Object]) practicing in SAN DIEGO, California with a Medicare Part D prescribing footprint of 858 claims across 233 beneficiaries . Industry payments of $328.57 across 3 transactions are disclosed under CMS Open Payments (Sunshine Act).

What stands out: MICHAEL CHAU, D.O. filed 858 Medicare Part D claims in 2023 across SAN DIEGO, California. Every figure on this page comes straight from federal CMS records, with no proprietary rating applied.

Board certification likely (heuristic — not verified)

MICHAEL CHAU, D.O. 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).

MICHAEL CHAU, D.O. at a glance

Quality data not reported

NPI registry status

Active

Issued 10/27/2015

NPI 1588036719

Primary specialty

Nephrology Physician

Mid-sized

10,534 US NPIs in this specialty

Medicare Part D claims

858 41% 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).

MICHAEL CHAU, D.O. is a Nephrology Physician provider practicing in SAN DIEGO, California, according to the CMS National Plan and Provider Enumeration System (NPPES). Credentials: D.O.. NPI: 1588036719. 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.

MICHAEL CHAU, D.O. appears in the CMS NPPES registry as a Nephrology Physician provider holding D.O. credentials at 4647 ZION AVE, SAN DIEGO, CA, 92120, with a listed phone of (877) 236-0333. NPI 1588036719 was issued on 10/27/2015. Because NPPES data is self-reported by the provider and refreshed monthly, the address, phone, and specialty reflect what CHAU 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 858 prescription claims written by this provider, covering 233 Medicare beneficiaries and totaling roughly $224K 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

4647 ZION AVE
SAN DIEGO, CA 92120

Provider Details

NPI 1588036719
Specialty Nephrology Physician
Credentials D.O.
Gender Male
NPI Issued 10/27/2015

Hospital and facility affiliations

Facilities where MICHAEL CHAU, D.O. 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.

SOUTHERN CALIFORNIA PERMANENTE MEDICAL GROUP
SAN MARCOS, 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 MICHAEL CHAU, D.O.. Source: openpaymentsdata.cms.gov.

Total received

$329

Largest payer

Stryker Corporation

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 MICHAEL CHAU, D.O.. To verify MICHAEL CHAU, D.O.'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.

Medicare Part D Prescribing Data

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

858
Total Claims
$224K
Total Drug Cost
233
Medicare Beneficiaries

Prescribing Breakdown

30-Day Fills
1,887
Total Day Supply
56,256
Generic Drug Cost
$40K

Patient Demographics

Average Patient Age
74.1 years
Avg HCC Risk Score
3.53
Gender Split
55% female / 45% male
Age Distribution
<65: 27, 65-74: 83, 75-84: 90, 85+: 33

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
147
Losartan Potassium
103
Veltassa
Patiromer Calcium Sorbitex
76
Hydralazine Hcl
54
Farxiga
Dapagliflozin Propanediol
50
Furosemide
34
Lisinopril
29
Sevelamer Carbonate
29
Nifedipine Er
Nifedipine
24
Atorvastatin Calcium
22

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

Nephrology Physician Overview

How MICHAEL CHAU, D.O. 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

MICHAEL CHAU, D.O.'s 858 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 CHAU.

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

Frequently Asked Questions

What is MICHAEL CHAU, D.O.'s specialty?
MICHAEL CHAU, D.O. specializes in Nephrology Physician and practices in SAN DIEGO, California. Credentials: D.O..
How much does MICHAEL CHAU, D.O. prescribe under Medicare Part D?
In 2023, MICHAEL CHAU, D.O. wrote 858 Medicare Part D claims totaling $224K in drug costs for 233 beneficiaries.
Where is MICHAEL CHAU, D.O. located?
MICHAEL CHAU, D.O. is located at 4647 ZION AVE, SAN DIEGO, CA, 92120. Phone: (877) 236-0333.
What is MICHAEL CHAU, D.O.'s NPI number?
MICHAEL CHAU, D.O.'s National Provider Identifier (NPI) is 1588036719, issued on 10/27/2015.
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 MICHAEL CHAU, D.O. prescribe most often?
Based on 2023 Medicare Part D data, MICHAEL CHAU, D.O.'s most frequently prescribed drugs include Amlodipine Besylate, Losartan Potassium, Veltassa. This reflects Medicare Part D prescriptions only and does not include commercial insurance or other payer types.
Does MICHAEL CHAU, D.O. accept Medicare?
MICHAEL CHAU, D.O. appears in CMS Medicare data with 858 Part D claims and 233 Medicare beneficiaries in 2023. Contact the provider's office directly to confirm current Medicare enrollment and accepted plans.
How can I verify MICHAEL CHAU, D.O.'s credentials?
MICHAEL CHAU, D.O.'s NPI is 1588036719 with credentials D.O.. 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