NPI registry status
Active
2026 NPPES data Internal Medicine Physician NPI 1558504381 M.D.
Verify on CMS → Erin Cook, M.D.
Internal Medicine Physician in Los Angeles, 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 172,858 in Internal Medicine 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
5K
Medicare Part D claims · 440 beneficiaries · Internal Medicine Physician avg: 3K
Generic prescribing
88%
generic claims · 12% 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
Erin Cook, M.D. filed 5,352 Medicare Part D claims in 2023 as a Internal Medicine Physician in Los Angeles, California, prescribing 88% generic.
- 5K
- Part D claims, 2023
- 88%
- 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.
Erin Cook, M.D.'s Medicare Part D volume vs every U.S. prescriber
Total Medicare Part D claims, 2023, across all CMS prescribers nationally
5,352 Top 6% higher than 94% 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)
Erin Cook, 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 Erin Cook, M.D.?
Quality data not reportedPrimary specialty
Internal Medicine Physician
Medicare Part D claims
5,352 97% vs specialty avg
Specialty distribution in California
How Internal Medicine 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 Internal Medicine 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).
Erin Cook, M.D. appears in the CMS NPPES registry as a Internal Medicine Physician provider holding M.D. credentials at 200 UCLA MEDICAL PLZ, Los Angeles, CA, 90095, with a listed phone of (310) 206-8272. NPI 1558504381 was issued on 04/09/2009.
Medicare Part D records for calendar year 2023 show 5,352 prescription claims written by this provider, covering 440 Medicare beneficiaries and totaling roughly $568K in drug spend, split 12% brand-name and 88% generic by claim count, with an opioid prescribing rate of 1.4%.
Internal Medicine Physician is a high-volume specialty nationwide, with 172,858 enrolled providers across 56 states and an average of 2,716 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 | 1558504381 |
|---|---|
| Specialty | Internal Medicine Physician |
| Credentials | M.D. |
| Gender | Female |
| NPI Issued | 04/09/2009 |
Hospital and facility affiliations
Facilities where Erin Cook, 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.
The Regents OF The University OF California
Los Angeles, 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 Erin Cook, M.D.. To verify Erin Cook, 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 · Typical
Erin Cook, M.D. - brand share 12.0%
Internal Medicine Physician average
12% brand-name claims vs 88% generic, on 5,352 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.
5,352
Total Claims
$568K
Total Drug Cost
440
Medicare Beneficiaries
Prescribing Breakdown
- 30-Day Fills
- 11,492
- Total Day Supply
- 335,906
- Brand vs Generic
- 12% brand / 88% generic
- Brand Drug Cost
- $409K
- Generic Drug Cost
- $158K
- Opioid Claims
- 74 (1.4% rate)
- Antibiotic Claims
- 66
Patient Demographics
- Average Patient Age
- 83.8 years
- Avg HCC Risk Score
- 1.94
- Gender Split
- 69% female / 31% male
Top Prescribed Drugs (Medicare Part D)
Top drugs by claim count for calendar year 2023. Based on Medicare Part D data only.
What Erin Cook, M.D. prescribes most
Top Medicare Part D drugs by claim count, 2023
- Atorvastatin Calcium
Atorvastatin Calcium
428 claims
- Levothyroxine Sodium
Levothyroxine Sodium
275 claims
- Amlodipine Besylate
Amlodipine Besylate
267 claims
- Losartan Potassium 170
Losartan Potassium
170 claims
- Donepezil Hcl 134
Donepezil Hcl
134 claims
- Mirtazapine 132
Mirtazapine
132 claims
- Alendronate Sodium 127
Alendronate Sodium
127 claims
- Lisinopril 118
Lisinopril
118 claims
| Drug | Claims |
|---|---|
| Atorvastatin Calcium | 428 |
| Levothyroxine Sodium | 275 |
| Amlodipine Besylate | 267 |
| Losartan Potassium | 170 |
| Donepezil Hcl | 134 |
| Mirtazapine | 132 |
| Alendronate Sodium | 127 |
| Lisinopril | 118 |
| Citalopram Hbr Citalopram Hydrobromide | 117 |
| Furosemide | 114 |
* Counts below 11 are suppressed by CMS for patient privacy. Generic names shown where available from CMS Part D data.
Internal Medicine Physician Overview
How Erin Cook, M.D. fits within the Internal Medicine Physician landscape nationally.
172,858
Internal Medicine Physician Providers in US
56
States with Internal Medicine Physician
2,716
Avg Claims per Provider
Erin Cook, M.D.'s 5,352 claims are above the specialty average of 2,716.
Nearby Internal Medicine Physician Providers in California
Other clinicians with the same primary specialty enrolled in California, drawn from the same CMS NPPES roster as Cook.
Dr. Jacob Aaron
MD
San Francisco, CA
Dr. Alistair Aaronson
MD
Stanford, CA
Dr. Jose Abad.
MD
Sacramento, CA
Dr. Donna Abare
MD
Oakland, CA
Marce Abare
Scotts Valley, CA
Compare Internal Medicine 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 Internal Medicine 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 Erin Cook, M.D.'s specialty? ▼
Erin Cook, M.D. specializes in Internal Medicine Physician and practices in Los Angeles, California. Credentials: M.D..
How much does Erin Cook, M.D. prescribe under Medicare Part D? ▼
In 2023, Erin Cook, M.D. wrote 5,352 Medicare Part D claims totaling $568K in drug costs for 440 beneficiaries.
Where is Erin Cook, M.D. located? ▼
Erin Cook, M.D. is located at 200 UCLA MEDICAL PLZ, Los Angeles, CA, 90095. Phone: (310) 206-8272.
What is Erin Cook, M.D.'s NPI number? ▼
Erin Cook, M.D.'s National Provider Identifier (NPI) is 1558504381, issued on 04/09/2009.
Does Erin Cook, M.D. prescribe more brand-name or generic drugs? ▼
Erin Cook, M.D.'s prescribing is 12% brand-name and 88% generic drugs by claim count, with $409K in brand drug costs.
Does Erin Cook, M.D. prescribe opioids? ▼
Yes, Erin Cook, M.D. had 74 opioid claims in 2023 with an opioid prescribing rate of 1.4%.
How many Internal Medicine Physician providers are there in the US? ▼
There are 172,858 Internal Medicine Physician providers across 56 states in the US. The average Internal Medicine Physician provider writes 2,716 Medicare Part D claims per year.
What drugs does Erin Cook, M.D. prescribe most often? ▼
Based on 2023 Medicare Part D data, Erin Cook, M.D.'s most frequently prescribed drugs include Atorvastatin Calcium, Levothyroxine Sodium, Amlodipine Besylate. This reflects Medicare Part D prescriptions only and does not include commercial insurance or other payer types.
Does Erin Cook, M.D. accept Medicare? ▼
Erin Cook, M.D. appears in CMS Medicare data with 5,352 Part D claims and 440 Medicare beneficiaries in 2023. Contact the provider's office directly to confirm current Medicare enrollment and accepted plans.
How can I verify Erin Cook, M.D.'s credentials? ▼
Erin Cook, M.D.'s NPI is 1558504381 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.