Courtney Ann O'Brien, DO
Rheumatology Physician · Simi Valley, CA
Courtney Ann O'Brien, DO is a rheumatology physician with a practice address in Simi Valley, California, and NPI 1609396514, issued on Jun 21, 2017. Check the license (California 20A18469, as entered in NPPES) on the Medical Board of California; the Medicare figures below come from public CMS files.
- Name
- Courtney Ann O'Brien
- Credential
- DO
- Primary taxonomy
- Rheumatology Physician 207RR0500X
- License number
- 20A18469 CA
Self-reported in NPPES; status is on the state search - Practice location
- 2655 1St St Ste 380, Simi Valley, CA 93065
- Phone
- (805) 583-7640
- Enumerated
- Jun 21, 2017
- Record last updated
- Jul 29, 2022
- Fax
- (805) 583-7641
- Medicare enrollment
- Enrolled (PECOS I20220616001464); accepts Medicare assignment
- Medical or professional school
- Nova Southeastern College Of Osteo Medicine, 2017
- Telehealth
- Offers telehealth (CMS)
- Entity
- Type 1 · individual
8 nearest rheumatology physician records → All 926 in California → Look up another NPI →
Also registered at 2655 1St St Ste 380
A shared address usually means a shared clinic or building; it does not show who employs whom.
- Miguel Rodrigo Estrera, AGACNP-BCNurse Practitioner1134980923
- Caroline Go, FNPNurse Practitioner1881308823
Verify Courtney Ann O'Brien in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersMedical Board of California
Search for license 20A18469Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
33% fewer Medicare Part D claims than the average rheumatology physician in 2024
1,327 Medicare Part D claims for 266 beneficiaries, against an average of 1,978 among the 6,301 providers of this specialty who prescribed in Part D. 28 claims were for opioids.
Most prescribed
- Hydroxychloroquine Sulfate150 claims
- Gabapentin110 claims
- Methotrexate105 claims
- Prednisone105 claims
- Meloxicam71 claims
- Duloxetine Hcl44 claims
Source: CMS Medicare Part D Prescribers by Provider and Drug, 2024 (data.cms.gov). Part D covers prescriptions for Medicare patients only; drugs with fewer than 11 claims are not published.
The practice group's MIPS final score for 2023 (Medicare payment program): 86.1 of 100
The Merit-based Incentive Payment System score is reported for the practice group, not for one clinician alone. Four categories are weighted into the final score; the average among 454,083 clinicians with a measured score was 83.5.
Source: CMS Quality Payment Program, MIPS performance year 2023, group reporting; category weights for 2023 (qpp.cms.gov).
Industry payments in 2024: $294.40
5 payments; by number, the most common kind was food and beverage; the largest payer was Aurinia Pharma U.S., Inc. The 4,486 providers of this specialty with any payment received $8,538.33 on average. Payments are reported by manufacturers, not by the provider, and are not a sign of wrongdoing.
Source: CMS Open Payments, program year 2024 (openpaymentsdata.cms.gov); average among providers of this specialty with at least one payment.
Bills Medicare through one group practice
- The Regents OF The University OF CaliforniaLos Angeles, CA
Source: CMS Doctors and Clinicians National Downloadable File (the group practices a clinician bills Medicare through) (data.cms.gov).
Courtney Ann O'Brien among 926 rheumatology physician records in California
Courtney Ann O'Brien, DO is one of 926 rheumatology physician records with a practice address in California. 81% of them appear in a Medicare file (Part D prescribing, MIPS, Open Payments or Medicare group billing); this one does. Its NPI, issued in 2017, is newer than 88% of them.
- NPI issued2017 · 88% of these records are older, 10% newer
- In a Medicare fileYes · 81% of these records are
- In the CMS Doctors and Clinicians fileYes · 69% of these records are
- Graduated2017 · median 2003 among the 641 with a school on file
- Record last updated2022 · 62% of these records were not updated in five years or more
Source: CMS NPPES, file of Aug 9, 2026, every record with primary taxonomy 207RR0500X and a California practice address; Medicare files: CMS Part D Prescribers 2024, MIPS 2023, Open Payments 2024, Doctors and Clinicians (data.cms.gov).
Rheumatology Physician providers in California
There are 926 rheumatology physician records in California.
All 926 in California → Every provider in Simi Valley → Rheumatology Physician nationwide →
The 8 rheumatology physician records with the nearest ZIP codes
- Tony Makhlouf, MDSimi Valley, CA 930651992932214
- Angelica Shepard, MDOxnard, CA 930361447546684
- Howard Hoos, MDOxnard, CA 930301114939287
- Timothy Spiegel, M.D.Santa Barbara, CA 931011700870243
- Erin Hammett, DO.Santa Barbara, CA 931051467884098
- Robert Klein, M.D.Santa Barbara, CA 931051205004900
- Wonuk Lee, M.D.Santa Barbara, CA 931051386720092
- Courtney Stull, M.D.Santa Barbara, CA 931051376905836
Common questions
What is Courtney Ann O'Brien, DO's NPI number?
Courtney Ann O'Brien, DO's National Provider Identifier (NPI) is 1609396514, issued on Jun 21, 2017. An NPI identifies a provider in billing; it is not a license.
Where is Courtney Ann O'Brien, DO located?
The NPPES record lists a practice address at 2655 1St St Ste 380, Simi Valley, CA, 93065. Phone: (805) 583-7640. Providers update this record themselves, so call before visiting.
How can I verify Courtney Ann O'Brien, DO's license?
NPPES lists California license number 20A18469, as entered by the provider. Search the Medical Board of California at https://www.mbc.ca.gov/License-Verification/default.aspx. The NPPES record confirms identity only; the state search shows license status, expiration and public orders.
How much does Courtney Ann O'Brien, DO prescribe under Medicare Part D?
In 2024, Courtney Ann O'Brien, DO had 1,327 Medicare Part D claims for 266 beneficiaries; the average among rheumatology physician prescribers was 1,978. Part D covers Medicare prescriptions only.
What is Courtney Ann O'Brien, DO's MIPS final score?
The 2023 MIPS final score is 86.1 of 100, reported for the practice group. The average among 454,083 clinicians with a measured score was 83.5.
Source: CMS National Plan and Provider Enumeration System (NPPES), file of Aug 9, 2026 (NPPES files on CMS.gov); NUCC Health Care Provider Taxonomy. Medicare files from data.cms.gov. An NPI identifies who bills; it is not a license.
Figures on PlainDoctor are read from the federal files each page names (CMS NPPES, Medicare Part D, MIPS, Open Payments; the HHS-OIG exclusion list only as counts) and from Census population estimates, with the file date shown beside them. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of Aug 9, 2026.