Dr. James C.s. Hahn, MD
- Medicare services, 2024
- 109
- Medicare patients, 2024
- 53
- Part D claims, 2024
- 8,792
- Hospital affiliations
- 1
- Industry payments
- $11,718
- Practice address
- 1245 W Wilshire Blvd, Los Angeles, CA 90017
- Practice phone
- Call (323) 735-1111
- Professional email
- Get professional email
- Personal email
- Get personal email
- Mobile number
- Get mobile number
Primary practice
James C.S. Hahn, M.D. , Inc.
Los Angeles, California
Find Dr. Hahn's professional email, personal email and mobile number
Dmand AI checks each channel through healthcare-specific waterfall enrichment. See what is on file with a free account, with practice phones, licenses and affiliations.
Dr. James C.s. Hahn is an internist in Los Angeles, California
Dr. Hahn practices at James C.S. Hahn, M.D. , Inc. in Los Angeles, California.
Dr. Hahn's NPI, 1033293634, was assigned on October 24, 2006. Dr. Hahn graduated from Yonsei University College of Medicine in 1975. Dr. Hahn holds California license A36933.
- NPI
- 1033293634NPI Registry (opens in a new tab)
- Medicare PAC ID
- 4587822382
- NPI enumeration date
- October 24, 2006
- NPI status
- Active
- Accepts Medicare assignment
- Yes
- Practice phone
- (323) 735-1111
- Professional email
- Get email
- Personal email
- Get email
- Mobile number
- Get number
- Sex
- Male
- Estimated age
- 77
- Medical school graduation
- 1975
Sources: NPPES NPI Registry (CMS); Dmand AI Professional Profile Data; Dmand AI Practice Data; and Doctors and Clinicians National Downloadable File (CMS)
Dr. James C.s. Hahn practices at James C.S. Hahn, M.D. , Inc. in Los Angeles, California
Dr. Hahn's primary practice is James C.S. Hahn, M.D. , Inc., at 1245 W Wilshire Blvd, Los Angeles, CA 90017 in Los Angeles County. The practice phone is (323) 735-1111.
- James C.S. Hahn, M.D. , Inc.1245 W Wilshire Blvd, Los Angeles, CA 90017 · Los Angeles CountyPhone(323) 735-1111
Sources: NPPES NPI Registry (CMS); and Dmand AI Practice Data
Dr. James C.s. Hahn is affiliated with 2 sites of care and 1 medical group
Dr. Hahn's primary practice is James C.S. Hahn, M.D. , Inc. in Los Angeles, California. Dr. Hahn is also affiliated with PIH Health Good Samaritan Hospital. The medical group on file is James C.S. Hahn, M.D., Inc.
Sources: NPPES NPI Registry (CMS); Dmand AI Practice Data; Dmand AI Affiliation Data; and Dmand AI Org Hierarchy Data
Dmand AI tracks the EHR system at Dr. James C.s. Hahn's practice
Dmand AI tracks the electronic health record (EHR) system at each site where Dr. Hahn practices. Vendor and product names are available with a free account.
| Site | EHR vendor and product |
|---|---|
| James C.S. Hahn, M.D. , Inc. | Available with a free account |
| +1 more affiliated site | Available with a free account |
Source: Dmand AI Technology Install Data
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Dr. James C.s. Hahn is one of 16,751 internists in California
Internal medicine is Dr. Hahn's primary specialty in the NPI Registry, under taxonomy code 207R00000X. Dr. Hahn is board certified in internal medicine by the American Board of Internal Medicine. Dr. Hahn is licensed in California.
Specialties and state licenses
- Internal medicine, CaliforniaPrimary
Clinical focus
Dmand AI lists aneurysm, aortic atherosclerois, arthritis, chronic hypertension, fibromyalgia and chronic pain, high cholesterol, irritable bowel syndrome (IBS) and thoracic spine disorders among the conditions Dr. Hahn treats.
Internists near Dr. Hahn
Counts of internists with a Dmand AI profile, by place and practice. Each opens the list.
Sources: NPPES NPI Registry (CMS); Dmand AI Professional Profile Data; and Dmand AI Peer Benchmarks
Dr. James C.s. Hahn billed Medicare for 109 services in 2024
CMS data shows 109 Medicare services from Dr. Hahn across 3 procedure codes in 2024, for 53 Medicare patients. Medicare paid $5,957 for them. Every service was in an office.
Dr. Hahn's Medicare services by type, 2023 to 2024
- 2023
- 2024
- Office and hospital visits
- 2023: 2472024: 7968%
- Other services
- 2023: 02024: 30
Dr. Hahn compared with the California median for internists, 2024
- Dr. Hahn
- California median
- Medicare services
- 109vs 36170% below
- Medicare patients
- 53vs 15165% below
- Part D claims
- 8,255vs 42119.6 times
Medians across 15,815 internists in California with Dmand AI profiles that report each measure.
Dr. Hahn's most billed Medicare procedure codes, 2024
CMS publishes codes billed for 11 or more Medicare patients. Each label is the code family; CPT descriptions are licensed by the AMA.
Need commercial claims for Dr. Hahn?
Medicare shows one payer. Book a meeting to get commercial claims data for Dr. Hahn and other internists in California.
Sources: Medicare Physician & Other Practitioners - by Provider and Service (CMS), 2024 data; and Dmand AI Peer Benchmarks
Dr. James C.s. Hahn treated 53 Medicare patients in 2024, average age 77
CMS counts 53 Medicare patients who saw Dr. Hahn in 2024. The largest group is 65 to 74, with 25 patients. 75% of them have high blood pressure, and 75% have high cholesterol. 34% are also on Medicaid. Their average risk score is 0.95, where 1.00 is the Medicare average.
Across all payers, Dmand AI patient panel data puts Dr. Hahn's median patient age at 66, with 53% women.
Dr. Hahn's Medicare patients by age, 2024
Dr. Hahn's Medicare patients by sex, 2024
- Women3362%
- Men2038%
Chronic conditions among Dr. Hahn's Medicare patients, 2024
- High blood pressure75%
- High cholesterol75%
- Diabetes40%
- Arthritis38%
- Depression25%
- Mood disorders25%
- Osteoporosis25%
- Heart failure21%
Share of Medicare patients with each condition. A patient can have several.
Dr. Hahn's patients across all payers
Dmand AI patient panel data covers Medicare, Medicaid and commercial patients.
Patient panel by age, all payers
Median age 66
Patient panel by sex, all payers
- Women53%
- Men45%
Sources: Dmand AI Patient Panel Data; and Medicare Physician & Other Practitioners - by Provider (CMS), 2024 data
Dr. James C.s. Hahn wrote 8,792 Medicare Part D claims in 2024
In 2024, Dr. Hahn wrote 8,792 Medicare Part D claims for 643 patients. 81% of them were for generic drugs. CMS names the drug for 8,255 of them, across 116 drugs with 11 or more claims each, at $1,036,353 in total drug cost. In 2023, CMS named 10,633 claims across 122 drugs.
Dr. Hahn's Part D claims by kind of drug, 2024
- Generic7,160 claims81%
- Brand-name1,573 claims18%
- Other59 claims1%
Dr. Hahn's most prescribed drugs by claims, 2024
CMS names a drug when it has 11 or more claims. Share is of the claims for drugs CMS names.
Drug classes CMS tracks in Dr. Hahn's Part D claims, 2024
- Opioids0%16 of 8,792 claims
- Antibiotics2%153 of 8,792 claims
Share of all Part D claims for each drug class CMS reports on. Classes with no claims are left out.
Part D claims for drugs CMS names, 2023 to 2024
- 2023
- 2024
- Claims for drugs CMS names
- 2023: 10,6332024: 8,25522%
Drugs named by CMS: 116 in 2024, 122 in 2023.
Sources: Medicare Part D Prescribers - by Provider and Drug (CMS), 2024 data, released May 6, 2026; and Medicare Part D Prescribers - by Provider (CMS), 2024 data
How Dr. James C.s. Hahn takes part in Medicare
Dr. Hahn accepts Medicare assignment, so Medicare's approved amount is taken as full payment.
- Accepts Medicare assignment
- Yes
Source: Doctors and Clinicians National Downloadable File (CMS)
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Dr. James C.s. Hahn received $11,718 in industry payments from 2016 to 2025
CMS Open Payments shows 448 general payments to Dr. Hahn from 31 drug and device companies from 2016 to 2025. Food and beverage make up the largest share, 81% of the total. Gilead Sciences, Inc. paid the most, $4,483.
General payments to Dr. Hahn by program year, 2016 to 2025
General payments to Dr. Hahn by kind, 2016 to 2025
- Food and beverage$9,45681%
- Consulting fees$1,70015%
- Travel and lodging$4984%
- Education$641%
Companies that paid Dr. Hahn the most, 2016 to 2025
Share is of all general payments to this clinician.
Source: Open Payments (CMS), 2025 data, released July 7, 2026
Dr. James C.s. Hahn has 1 award and honors on record
Dmand AI lists 1 award for Dr. Hahn, most recently CMS Stage 1 EHR in 2013.
Awards and honors for Dr. Hahn
- 2013
- CMS Stage 1 EHR
Source: Dmand AI Professional Profile Data
Dr. James C.s. Hahn graduated from Yonsei University College of Medicine
Dr. Hahn graduated from Yonsei University College of Medicine in 1975.
- Medical school
- Board certified in internal medicine
Source: Dmand AI Professional Profile Data
Dr. James C.s. Hahn accepts plans from 7 insurance carriers
Dr. Hahn is in network with 7 carriers, including Aetna, Elevance and Blue Cross Blue Shield of Michigan. Medicare plans come from the most carriers, 7. Check the plan with the practice before a visit.
- Aetna
- Elevance
- Blue Cross Blue Shield of Michigan
- Blue Cross Blue Shield of Massachusetts
- Regence Health Plans
- CMS Medicare
- Molina
Plan types Dr. Hahn accepts, by number of carriers
- Medicare7
- PPO5
- HMO3
- POS3
- EPO2
Source: Dmand AI Insurance Network Data
Sources for Dr. James C.s. Hahn's profile data
| Data on this page | Source |
|---|---|
| NPI, name, sex, specialty and licenses | NPPES NPI Registry (CMS) (opens in a new tab)Dmand AI Professional Profile Data |
| Practice locations and phone | NPPES NPI Registry (CMS) (opens in a new tab)Dmand AI Practice Data |
| Primary practice, affiliations and health system | NPPES NPI Registry (CMS) (opens in a new tab)Dmand AI Practice DataDmand AI Affiliation DataDmand AI Org Hierarchy Data |
| Medicare services and procedure codes | Medicare Physician & Other Practitioners - by Provider and Service (CMS) (opens in a new tab) |
| State medians for the same specialty | Dmand AI Peer Benchmarks |
| Medicare patients and the all-payer patient panel | Dmand AI Patient Panel DataMedicare Physician & Other Practitioners - by Provider (CMS) (opens in a new tab) |
| Part D prescribing | Medicare Part D Prescribers - by Provider and Drug (CMS) (opens in a new tab)Medicare Part D Prescribers - by Provider (CMS) (opens in a new tab) |
| MIPS scores, telehealth, assignment and procedure percentiles | Doctors and Clinicians National Downloadable File (CMS) (opens in a new tab) |
| Industry payments | Open Payments (CMS) (opens in a new tab) |
| Awards and committee roles | Dmand AI Professional Profile Data |
| Training, board certification and memberships | Dmand AI Professional Profile Data |
| Insurance carriers and plan types | Dmand AI Insurance Network Data |
| EHR at each practice site | Dmand AI Technology Install Data |
| Similar physicians | Dmand AI Affiliation Data |
Data last refreshed October 2026Report an inaccuracyRemove my information
FAQ
Frequently asked questions about Dr. James C.s. Hahn
Spotted something out of date? Email hello@dmand.ai and we will check the record. Contact details live in the free trial.
What is Dr. James C.s. Hahn's NPI number?
Dr. James C.s. Hahn's NPI number is 1033293634. It was assigned on October 24, 2006, and it is active in the NPI Registry.
What kind of doctor is Dr. James C.s. Hahn?
Dr. James C.s. Hahn is an internist in Los Angeles, California. The primary specialty in the NPI Registry is Internal Medicine Physician (taxonomy code 207R00000X).
Where does Dr. James C.s. Hahn practice?
Dr. Hahn practices at 1245 W Wilshire Blvd, Los Angeles, CA 90017. Dr. Hahn's primary practice is James C.S. Hahn, M.D. , Inc. in Los Angeles, California.
What is Dr. James C.s. Hahn's office phone number?
The practice phone on file for Dr. Hahn is (323) 735-1111.
What is Dr. James C.s. Hahn's medical license number?
Dr. Hahn holds California license A36933.
Which hospitals is Dr. James C.s. Hahn affiliated with?
Dr. Hahn is affiliated with PIH Health Good Samaritan Hospital.
What medical group is Dr. James C.s. Hahn part of?
Dr. Hahn is linked to James C.S. Hahn, M.D., Inc.
Does Dr. James C.s. Hahn accept Medicare?
Yes. CMS data shows Dr. Hahn billed Medicare for 109 services in 2024, and Dr. Hahn accepts Medicare assignment.
How many Medicare patients does Dr. James C.s. Hahn see?
CMS counts 53 Medicare patients who saw Dr. Hahn in 2024, with an average age of 77.
Is Dr. James C.s. Hahn board certified?
Yes. Dr. Hahn is board certified in internal medicine by the American Board of Internal Medicine.
Show 6 more questionsShow fewer questions
What services does Dr. James C.s. Hahn bill to Medicare?
In 2024, Dr. Hahn's most billed Medicare services were office visit, established patient (99214), medicare service (G2211) and medicare service (G0439).
Where did Dr. James C.s. Hahn go to medical school?
Dr. Hahn graduated from Yonsei University College of Medicine in 1975.
What drugs does Dr. James C.s. Hahn prescribe most?
In 2024 Medicare Part D data, Dr. Hahn's most prescribed drugs by claims were Atorvastatin Calcium, Losartan Potassium and Amlodipine Besylate.
Has Dr. James C.s. Hahn received payments from drug or device companies?
CMS Open Payments shows $11,718 in general payments to Dr. Hahn from 31 companies from 2016 to 2025. The largest total came from Gilead Sciences, Inc.
How long has Dr. James C.s. Hahn been practicing?
Dr. Hahn graduated from medical school in 1975, 51 years ago.
What insurance does Dr. James C.s. Hahn accept?
Dr. Hahn is in network with 7 carriers, including Aetna, Elevance and Blue Cross Blue Shield of Michigan. Medicare plans come from the most carriers, 7. Check the plan with the practice before a visit.
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