2026 NPPES data Hospitalist Physician NPI 1134418171 M.D.
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BRIAN APTER, M.D.

Hospitalist Physician in PASADENA, California. CMS National Plan and Provider Enumeration System profile including specialty classification, practice address, and Medicare prescribing data when reported.

Federal data — no proprietary rating. PlainDoctor publishes the actual CMS NPPES and Medicare records — NPI registration, specialty, practice location, and prescribing data — without a composite score or editorial opinion on top. Every field traces to a federal source.
Prescribing volume
569
Medicare Part D claims · 172 beneficiaries · Hospitalist Physician avg: 888
Generic prescribing
87%
generic claims · 13% brand-name · higher generic rates reduce patient out-of-pocket costs
What the federal data reveals: BRIAN APTER, M.D. is a Hospitalist Physician ([object Object]) practicing in PASADENA, California with a Medicare Part D prescribing footprint of 569 claims across 172 beneficiaries — 13% brand-name prescribing .

What stands out: BRIAN APTER, M.D. filed 569 Medicare Part D claims in 2023 across PASADENA, California. Every figure on this page comes straight from federal CMS records, with no proprietary rating applied.

Board certification likely (heuristic — not verified)

BRIAN APTER, 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).

BRIAN APTER, M.D. at a glance

Quality data not reported

NPI registry status

Active

Issued 03/30/2011

NPI 1134418171

Primary specialty

Hospitalist Physician

Mid-sized

16,825 US NPIs in this specialty

Medicare Part D claims

569 36% vs specialty avg

2023 prescription claims

Specialty avg: 888

Specialty distribution in California

How Hospitalist Physician compares to other specialties among California providers

California providers

Hospitalist Physician share within California

1. Hospitalist Physician42%2. Internal medicine21%3. Family medicine17%4. Surgical12%5. Pediatric8%
Hospitalist Physician share within California

Specialty board-certification context

Estimated specialty board-certified rate — Hospitalist Physician (ABMS / AOA reference)

Quality data not reported
Est. board-certified rate
78%
Hospitalist Physician ABMS/AOA estimate

Est. board-certified rate (Hospitalist Physician) — ABMS / AOA estimate

0%100%78%
Est. board-certified rate (Hospitalist Physician) — ABMS / AOA estimate

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).

BRIAN APTER, M.D. is a Hospitalist Physician provider practicing in PASADENA, California, according to the CMS National Plan and Provider Enumeration System (NPPES). Credentials: M.D.. NPI: 1134418171. This profile includes practice location, specialty classification, and organizational affiliations from the CMS provider registry. Provider information is self-reported to CMS and updated monthly.

BRIAN APTER, M.D. appears in the CMS NPPES registry as a Hospitalist Physician provider holding M.D. credentials at 393 E WALNUT ST, PASADENA, CA, 91188, with a listed phone of (415) 310-1938. NPI 1134418171 was issued on 03/30/2011. Because NPPES data is self-reported by the provider and refreshed monthly, the address, phone, and specialty reflect what APTER most recently submitted to CMS rather than a vetted directory listing, which is why patients should always confirm the practice is still at this location before scheduling.

Medicare Part D records for calendar year 2023 show 569 prescription claims written by this provider, covering 172 Medicare beneficiaries and totaling roughly $34K in drug spend, split 13% brand-name and 87% generic by claim count. These figures capture only Medicare Part D — commercial insurance, Medicaid, and cash-pay prescriptions are not included, and any drug-beneficiary cell under 11 is suppressed by CMS for patient privacy.

Hospitalist Physician is a mid-sized specialty nationwide, with 16,825 enrolled providers across 54 states and an average of 888 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

393 E WALNUT ST
PASADENA, CA 91188

Provider Details

NPI 1134418171
Specialty Hospitalist Physician
Credentials M.D.
Gender Male
NPI Issued 03/30/2011

Hospital and facility affiliations

Facilities where BRIAN APTER, 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
RIVERSIDE, 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 BRIAN APTER, M.D.. To verify BRIAN APTER, 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

BRIAN APTER, M.D. — brand share 13.0%
Specialty average (est.)

13% brand-name claims vs 87% generic, on 569 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.

569
Total Claims
$34K
Total Drug Cost
172
Medicare Beneficiaries

Prescribing Breakdown

30-Day Fills
1,174
Total Day Supply
32,217
Brand vs Generic
13% brand / 87% generic
Brand Drug Cost
$22K
Generic Drug Cost
$12K
Antibiotic Claims
66

Patient Demographics

Average Patient Age
75.4 years
Avg HCC Risk Score
2.73
Gender Split
47% female / 53% male
Age Distribution
<65: 21, 65-74: 54, 75-84: 61, 85+: 36

Top Prescribed Drugs (Medicare Part D)

Top drugs by claim count for calendar year 2023. Based on Medicare Part D data only.

Drug Claims
Furosemide
38
Potassium Chloride
37
Amlodipine Besylate
35
Hydralazine Hcl
29
Atorvastatin Calcium
22
Isosorbide Mononitrate Er
Isosorbide Mononitrate
20
Metoprolol Tartrate
20
Cefpodoxime Proxetil
19
Pantoprazole Sodium
18
Losartan Potassium
17

* Counts below 11 are suppressed by CMS for patient privacy. Generic names shown where available from CMS Part D data.

Hospitalist Physician Overview

How BRIAN APTER, M.D. fits within the Hospitalist Physician landscape nationally.

16,825
Hospitalist Physician Providers in US
54
States with Hospitalist Physician
888
Avg Claims per Provider

BRIAN APTER, M.D.'s 569 claims are below the specialty average of 888.

Nearby Hospitalist Physician Providers in California

Other clinicians with the same primary specialty enrolled in California, drawn from the same CMS NPPES roster as APTER.

Compare Hospitalist Physician nationally: see state-by-state distribution →

Frequently Asked Questions

What is BRIAN APTER, M.D.'s specialty?
BRIAN APTER, M.D. specializes in Hospitalist Physician and practices in PASADENA, California. Credentials: M.D..
How much does BRIAN APTER, M.D. prescribe under Medicare Part D?
In 2023, BRIAN APTER, M.D. wrote 569 Medicare Part D claims totaling $34K in drug costs for 172 beneficiaries.
Where is BRIAN APTER, M.D. located?
BRIAN APTER, M.D. is located at 393 E WALNUT ST, PASADENA, CA, 91188. Phone: (415) 310-1938.
What is BRIAN APTER, M.D.'s NPI number?
BRIAN APTER, M.D.'s National Provider Identifier (NPI) is 1134418171, issued on 03/30/2011.
Does BRIAN APTER, M.D. prescribe more brand-name or generic drugs?
BRIAN APTER, M.D.'s prescribing is 13% brand-name and 87% generic drugs by claim count, with $22K in brand drug costs.
How many Hospitalist Physician providers are there in the US?
There are 16,825 Hospitalist Physician providers across 54 states in the US. The average Hospitalist Physician provider writes 888 Medicare Part D claims per year.
What drugs does BRIAN APTER, M.D. prescribe most often?
Based on 2023 Medicare Part D data, BRIAN APTER, M.D.'s most frequently prescribed drugs include Furosemide, Potassium Chloride, Amlodipine Besylate. This reflects Medicare Part D prescriptions only and does not include commercial insurance or other payer types.
Does BRIAN APTER, M.D. accept Medicare?
BRIAN APTER, M.D. appears in CMS Medicare data with 569 Part D claims and 172 Medicare beneficiaries in 2023. Contact the provider's office directly to confirm current Medicare enrollment and accepted plans.
How can I verify BRIAN APTER, M.D.'s credentials?
BRIAN APTER, M.D.'s NPI is 1134418171 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

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