Dr. Christopher Mark O'Brien, MD
- Medicare patients, 2024
- 12
- Part D claims, 2024
- 356
- Hospital affiliations
- 1
- Industry payments
- $174
- Medical group
- 1
- Practice address
- 9455 Clairemont Mesa Blvd, San Diego, CA 92123
- Practice phone
- Call (619) 528-5000
- Professional email
- Get professional email
- Personal email
- Get personal email
- Mobile number
- Get mobile number
Primary practice
Kaiser Permanente San Diego Medical Center
San Diego, California
Find Dr. O'Brien'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. Christopher Mark O'Brien is an infectious disease specialist in San Diego, California
Dr. O'Brien practices at Kaiser Permanente San Diego Medical Center in San Diego, California.
Dr. O'Brien's NPI, 1730250788, was assigned on November 13, 2006. Dr. O'Brien graduated from Cleveland Medical College, Homeopathic in 1998. Dr. O'Brien holds California license A70951.
- NPI
- 1730250788NPI Registry (opens in a new tab)
- Medicare PAC ID
- 1355303926
- NPI enumeration date
- November 13, 2006
- NPI status
- Active
- Accepts Medicare assignment
- Yes
- Practice phone
- (619) 528-5000
- Professional email
- Get email
- Personal email
- Get email
- Mobile number
- Get number
- Sex
- Male
- Estimated age
- 54
- Medical school graduation
- 1998
Sources: NPPES NPI Registry (CMS); Dmand AI Professional Profile Data; Dmand AI Practice Data; and Doctors and Clinicians National Downloadable File (CMS)
Dr. Christopher Mark O'Brien practices at Kaiser Permanente San Diego Medical Center in San Diego, California
Dr. O'Brien's primary practice is Kaiser Permanente San Diego Medical Center, at 9455 Clairemont Mesa Blvd, San Diego, CA 92123 in San Diego County. The practice phone is (619) 528-5000.
- Kaiser Permanente San Diego Medical Center9455 Clairemont Mesa Blvd, San Diego, CA 92123 · San Diego CountyPhone(619) 528-5000
Sources: NPPES NPI Registry (CMS); and Dmand AI Practice Data
Dr. Christopher Mark O'Brien is affiliated with 2 sites of care and 1 medical group
Dr. O'Brien's primary practice is Kaiser Permanente San Diego Medical Center in San Diego, California. Dr. O'Brien is also affiliated with Kaiser Permanente Zion Medical Center. The medical group on file is Southern California Permanente Medical Group.
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. Christopher Mark O'Brien's practice
Dmand AI tracks the electronic health record (EHR) system at each site where Dr. O'Brien practices. Vendor and product names are available with a free account.
| Site | EHR vendor and product |
|---|---|
| Kaiser Permanente San Diego Medical Center | 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. Christopher Mark O'Brien is one of 1,054 infectious disease specialists in California
Infectious disease is Dr. O'Brien's primary specialty in the NPI Registry, under taxonomy code 207RI0200X. Dr. O'Brien is board certified in infectious disease by the American Board of Internal Medicine. Dr. O'Brien is licensed in California.
Specialties and state licenses
- Infectious disease, CaliforniaPrimary
Infectious disease specialists near Dr. O'Brien
Counts of infectious disease specialists 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. Christopher Mark O'Brien treated 12 Medicare patients in 2024, average age 63
CMS counts 12 Medicare patients who saw Dr. O'Brien in 2024. Their average risk score is 2.63, where 1.00 is the Medicare average, so they are sicker than most Medicare patients.
Across all payers, Dmand AI patient panel data puts Dr. O'Brien's median patient age at 48, with 34% women.
Dr. O'Brien's patients across all payers
Dmand AI patient panel data covers Medicare, Medicaid and commercial patients.
Patient panel by age, all payers
Median age 48
Patient panel by sex, all payers
- Women34%
- Men66%
Sources: Dmand AI Patient Panel Data; and Medicare Physician & Other Practitioners - by Provider (CMS), 2024 data
Dr. Christopher Mark O'Brien wrote 356 Medicare Part D claims in 2024
In 2024, Dr. O'Brien wrote 356 Medicare Part D claims for 101 patients. 72% of them were for generic drugs. CMS names the drug for 224 of them, across 12 drugs with 11 or more claims each, at $186,674 in total drug cost. In 2023, CMS named 187 claims across 9 drugs.
Dr. O'Brien's Part D claims by kind of drug, 2024
- Generic257 claims72%
- Brand-name99 claims28%
Dr. O'Brien'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. O'Brien's Part D claims, 2024
- Antibiotics33%119 of 356 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: 1872024: 22420%
Drugs named by CMS: 12 in 2024, 9 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. Christopher Mark O'Brien takes part in Medicare
Dr. O'Brien 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. Christopher Mark O'Brien received $174 in industry payments in 2025
CMS Open Payments shows 1 general payment to Dr. O'Brien from 1 drug or device company in 2025. Food and beverage make up the largest share, 100% of the total. HeartFlow, Inc. paid the most, $174.
Companies that paid Dr. O'Brien the most, 2025 to 2025
Share is of all general payments to this clinician.
Source: Open Payments (CMS), 2025 data, released July 7, 2026
Dr. Christopher Mark O'Brien has 1 award and honors on record
Dmand AI lists 1 award for Dr. O'Brien, most recently CMS Stage 1 2012 in 2011.
Awards and honors for Dr. O'Brien
- 2011
- CMS Stage 1 2012
Source: Dmand AI Professional Profile Data
Dr. Christopher Mark O'Brien graduated from Cleveland Medical College, Homeopathic
Dr. O'Brien graduated from Cleveland Medical College, Homeopathic in 1998.
- Medical school
- Board certified in infectious disease
- Board certified in internal medicine
Source: Dmand AI Professional Profile Data
Dr. Christopher Mark O'Brien accepts plans from 2 insurance carriers
Dr. O'Brien is in network with 2 carriers, including Kaiser Permanente and CMS Medicare. EPO plans come from the most carriers, 1. Check the plan with the practice before a visit.
- Kaiser Permanente
- CMS Medicare
Plan types Dr. O'Brien accepts, by number of carriers
- EPO1
- HMO1
- Medicare1
- POS1
Source: Dmand AI Insurance Network Data
Sources for Dr. Christopher Mark O'Brien'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 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. Christopher Mark O'Brien
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. Christopher Mark O'Brien's NPI number?
Dr. Christopher Mark O'Brien's NPI number is 1730250788. It was assigned on November 13, 2006, and it is active in the NPI Registry.
What kind of doctor is Dr. Christopher Mark O'Brien?
Dr. Christopher Mark O'Brien is an infectious disease specialist in San Diego, California. The primary specialty in the NPI Registry is Infectious Disease Physician (taxonomy code 207RI0200X).
Where does Dr. Christopher Mark O'Brien practice?
Dr. O'Brien practices at 9455 Clairemont Mesa Blvd, San Diego, CA 92123. Dr. O'Brien's primary practice is Kaiser Permanente San Diego Medical Center in San Diego, California.
What is Dr. Christopher Mark O'Brien's office phone number?
The practice phone on file for Dr. O'Brien is (619) 528-5000.
What is Dr. Christopher Mark O'Brien's medical license number?
Dr. O'Brien holds California license A70951.
Which hospitals is Dr. Christopher Mark O'Brien affiliated with?
Dr. O'Brien is affiliated with Kaiser Permanente Zion Medical Center.
What medical group is Dr. Christopher Mark O'Brien part of?
Dr. O'Brien is linked to Southern California Permanente Medical Group.
Does Dr. Christopher Mark O'Brien accept Medicare?
Yes. CMS lists Dr. O'Brien as accepting Medicare assignment.
How many Medicare patients does Dr. Christopher Mark O'Brien see?
CMS counts 12 Medicare patients who saw Dr. O'Brien in 2024, with an average age of 63.
Is Dr. Christopher Mark O'Brien board certified?
Yes. Dr. O'Brien is board certified in infectious disease by the American Board of Internal Medicine.
Show 5 more questionsShow fewer questions
Where did Dr. Christopher Mark O'Brien go to medical school?
Dr. O'Brien graduated from Cleveland Medical College, Homeopathic in 1998.
What drugs does Dr. Christopher Mark O'Brien prescribe most?
In 2024 Medicare Part D data, Dr. O'Brien's most prescribed drugs by claims were Cephalexin, Doxycycline Monohydrate and Cresemba.
Has Dr. Christopher Mark O'Brien received payments from drug or device companies?
CMS Open Payments shows $174 in general payments to Dr. O'Brien from 1 company from 2025 to 2025. The largest total came from HeartFlow, Inc.
How long has Dr. Christopher Mark O'Brien been practicing?
Dr. O'Brien graduated from medical school in 1998, 28 years ago.
What insurance does Dr. Christopher Mark O'Brien accept?
Dr. O'Brien is in network with 2 carriers, including Kaiser Permanente and CMS Medicare. EPO plans come from the most carriers, 1. Check the plan with the practice before a visit.
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