NPI registry status
Active
2026 NPPES data Nephrology Physician NPI 1992894885 M.D.
Verify on CMS → Robert Chang, M.D.
Nephrology Physician in Corona, 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
2K
Medicare Part D claims · 420 beneficiaries · Nephrology Physician avg: 1K
Generic prescribing
90%
generic claims · 9% brand-name · higher generic rates reduce patient out-of-pocket costs
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
Robert Chang, M.D. filed 1,671 Medicare Part D claims in 2023 as a Nephrology Physician in Corona, California, prescribing 90% generic.
- 2K
- Part D claims, 2023
- 90%
- 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.
Robert Chang, M.D.'s Medicare Part D volume vs every U.S. prescriber
Total Medicare Part D claims, 2023, across all CMS prescribers nationally
1,671 Top 18% higher than 82% of 1,370,886 prescribers
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 certification likely (heuristic, not verified)
Robert Chang, M.D. 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).
What does the federal data show about Robert Chang, M.D.?
Quality data not reportedPrimary specialty
Nephrology Physician
Medicare Part D claims
1,671 15% vs specialty avg
Specialty distribution in California
How Nephrology Physician compares to other specialties among California providers
Board certification
Not published by CMS
CMS does not publish a per-provider board-certification field in NPPES. PlainDoctor does not have a reliable per-specialty certification rate to show for Nephrology Physician. Verify directly:
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).
Robert Chang, M.D. appears in the CMS NPPES registry as a Nephrology Physician provider holding M.D. credentials at 2057 COMPTON AVE, Corona, CA, 92881, with a listed phone of (951) 736-6757. NPI 1992894885 was issued on 10/11/2006.
Medicare Part D records for calendar year 2023 show 1,671 prescription claims written by this provider, covering 420 Medicare beneficiaries and totaling roughly $176K in drug spend, split 9% brand-name and 90% generic by claim count.
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 | 1992894885 |
|---|---|
| Specialty | Nephrology Physician |
| Credentials | M.D. |
| Gender | Male |
| NPI Issued | 10/11/2006 |
Hospital and facility affiliations
Facilities where Robert Chang, M.D. 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
Downey, 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).
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 Robert Chang, M.D.. To verify Robert Chang, M.D.'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 · Generic-heavy
Robert Chang, M.D. - brand share 9.0%
Nephrology Physician average
9% brand-name claims vs 90% generic, on 1,671 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.
1,671
Total Claims
$176K
Total Drug Cost
420
Medicare Beneficiaries
Prescribing Breakdown
- 30-Day Fills
- 4,635
- Total Day Supply
- 135,843
- Brand vs Generic
- 9% brand / 90% generic
- Brand Drug Cost
- $76K
- Generic Drug Cost
- $100K
- Antibiotic Claims
- 36
Patient Demographics
- Average Patient Age
- 71.3 years
- Avg HCC Risk Score
- 5.09
- Gender Split
- 51% female / 49% male
- Age Distribution
- <65: 91, 65-74: 141, 75-84: 141, 85+: 47
Top Prescribed Drugs (Medicare Part D)
Top drugs by claim count for calendar year 2023. Based on Medicare Part D data only.
What Robert Chang, M.D. prescribes most
Top Medicare Part D drugs by claim count, 2023
- Sevelamer Carbonate
Sevelamer Carbonate
150 claims
- Atorvastatin Calcium
Atorvastatin Calcium
141 claims
- Furosemide
Furosemide
107 claims
- Losartan Potassium
Losartan Potassium
104 claims
- Amlodipine Besylate
Amlodipine Besylate
102 claims
- Jardiance
Jardiance
88 claims
- Hydralazine Hcl
Hydralazine Hcl
85 claims
- Lisinopril
Lisinopril
82 claims
| Drug | Claims |
|---|---|
| Sevelamer Carbonate | 150 |
| Atorvastatin Calcium | 141 |
| Furosemide | 107 |
| Losartan Potassium | 104 |
| Amlodipine Besylate | 102 |
| Jardiance Empagliflozin | 88 |
| Hydralazine Hcl | 85 |
| Lisinopril | 82 |
| Calcitriol | 72 |
| Sodium Polystyrene Sulfonate | 52 |
* Counts below 11 are suppressed by CMS for patient privacy. Generic names shown where available from CMS Part D data.
Nephrology Physician Overview
How Robert Chang, M.D. 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
Robert Chang, M.D.'s 1,671 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 Chang.
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 Robert Chang, M.D.'s specialty? ▼
Robert Chang, M.D. specializes in Nephrology Physician and practices in Corona, California. Credentials: M.D..
How much does Robert Chang, M.D. prescribe under Medicare Part D? ▼
In 2023, Robert Chang, M.D. wrote 1,671 Medicare Part D claims totaling $176K in drug costs for 420 beneficiaries.
Where is Robert Chang, M.D. located? ▼
Robert Chang, M.D. is located at 2057 COMPTON AVE, Corona, CA, 92881. Phone: (951) 736-6757.
What is Robert Chang, M.D.'s NPI number? ▼
Robert Chang, M.D.'s National Provider Identifier (NPI) is 1992894885, issued on 10/11/2006.
Does Robert Chang, M.D. prescribe more brand-name or generic drugs? ▼
Robert Chang, M.D.'s prescribing is 9% brand-name and 90% generic drugs by claim count, with $76K 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 Robert Chang, M.D. prescribe most often? ▼
Based on 2023 Medicare Part D data, Robert Chang, M.D.'s most frequently prescribed drugs include Sevelamer Carbonate, Atorvastatin Calcium, Furosemide. This reflects Medicare Part D prescriptions only and does not include commercial insurance or other payer types.
Does Robert Chang, M.D. accept Medicare? ▼
Robert Chang, M.D. appears in CMS Medicare data with 1,671 Part D claims and 420 Medicare beneficiaries in 2023. Contact the provider's office directly to confirm current Medicare enrollment and accepted plans.
How can I verify Robert Chang, M.D.'s credentials? ▼
Robert Chang, M.D.'s NPI is 1992894885 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
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.
- 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.