2026 NPPES data Internal Medicine Physician NPI 1194813832 M.D.
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Stephen Oishi, M.D.

Internal Medicine Physician in Honolulu, Hawaii. 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 · 422 beneficiaries · Internal Medicine Physician avg: 3K
Generic prescribing
83%
generic claims · 16% brand-name · higher generic rates reduce patient out-of-pocket costs
Industry payments
$81.66
3 payments · CMS Open Payments (Sunshine Act)
Compiled from official public sources by the PlainDoctor editorial team.

What the federal data shows

Stephen Oishi, M.D. filed 4,666 Medicare Part D claims in 2023 as a Internal Medicine Physician in Honolulu, Hawaii, prescribing 83% generic.

5K
Part D claims, 2023
83%
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.

Stephen Oishi, M.D.'s Medicare Part D volume vs every U.S. prescriber

Total Medicare Part D claims, 2023, across all CMS prescribers nationally

4,666 Top 7% higher than 93% of 1,370,886 prescribers

0–200: 670,926 prescribers (49%). Below this entry. 200–400: 182,923 prescribers (13%). Below this entry. 400–600: 90,619 prescribers (7%). Below this entry. 600–800: 56,224 prescribers (4%). Below this entry. 800–1,000: 40,919 prescribers (3%). Below this entry. 1,000–1,200: 31,827 prescribers (2%). Below this entry. 1,200–1,400: 26,224 prescribers (2%). Below this entry. 1,400–1,600: 21,710 prescribers (2%). Below this entry. 1,600–1,800: 19,072 prescribers (1%). Below this entry. 1,800–2,000: 16,451 prescribers (1%). Below this entry. 2K+: 213,991 prescribers (16%). This entry sits in this band. This provider 0 2K+ every Part D prescriber (claims/yr), bucketed by value

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)

Stephen Oishi, 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 Stephen Oishi, M.D.?

Quality data not reported

NPI registry status

Active

Issued 10/10/2006

NPI 1194813832

Primary specialty

Internal Medicine Physician

High-volume

172,858 US NPIs in this specialty

Medicare Part D claims

4,666 72% vs specialty avg

2023 prescription claims

Specialty avg: 2,716

Specialty distribution in Hawaii

How Internal Medicine Physician compares to other specialties among Hawaii providers

Hawaii providers
Behavior Technician - 16.4%Behavior Technician16.4%Massage Therapist - 4.3%Massage Therapist4.3%Physical Therapist - 3.7%Physical Therapist3.7%Pharmacist - 3.7%Pharmacist3.7%Mental Health Counselor - 3.1%Mental Health Counselor3.1%Internal Medicine Physician - 3.1%Internal Medicine Physician3.1%
Largest specialties in Hawaii (% of in-state 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:

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).

Stephen Oishi, M.D. appears in the CMS NPPES registry as a Internal Medicine Physician provider holding M.D. credentials at 321 N KUAKINI ST, Honolulu, HI, 96817, with a listed phone of (808) 523-8611. NPI 1194813832 was issued on 10/10/2006. Because NPPES data is self-reported by the provider and refreshed monthly, the address, phone, and specialty reflect what Oishi 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 4,666 prescription claims written by this provider, covering 422 Medicare beneficiaries and totaling roughly $1.0 million in drug spend, split 16% brand-name and 83% 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.

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

321 N KUAKINI ST
Honolulu, HI 96817

Provider Details

NPI 1194813832
Specialty Internal Medicine Physician
Credentials M.D.
Gender Male
NPI Issued 10/10/2006

Hospital and facility affiliations

Facilities where Stephen Oishi, 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.

Queens University Medical Group
Honolulu, HI

Affiliations sourced from CMS Doctors and Clinicians National Downloadable File; hospital ratings from CMS Hospital General Information dataset (cross-referenced by facility name + state).

Industry payments received (2024) - CMS Open Payments transparency data

The federal Physician Payments Sunshine Act (part of the Affordable Care Act) requires drug and medical-device manufacturers + group purchasing organizations to publicly report payments and other transfers of value to physicians and teaching hospitals. The data below covers 2024 for Stephen Oishi, M.D.. Source: openpaymentsdata.cms.gov.

Total received

$82

Largest payer

AstraZeneca Pharmaceuticals LP

Most common payment type

Food and Beverage

Industry payments are not necessarily indicators of bias, they include research funding, consulting fees for evidence-based work, royalties for inventions, food at conferences, and similar items. The disclosure exists for transparency. Read our methodology for how we interpret this data.

Brand vs generic prescribing mix · Typical

Stephen Oishi, M.D. - brand share 16.0%
Internal Medicine Physician average

16% brand-name claims vs 83% generic, on 4,666 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.

4,666
Total Claims
$1.0M
Total Drug Cost
422
Medicare Beneficiaries

Prescribing Breakdown

30-Day Fills
13,063
Total Day Supply
389,249
Brand vs Generic
16% brand / 83% generic
Brand Drug Cost
$883K
Generic Drug Cost
$141K
Antibiotic Claims
21

Patient Demographics

Average Patient Age
79.3 years
Avg HCC Risk Score
1.76
Gender Split
55% female / 45% male

Top Prescribed Drugs (Medicare Part D)

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

What Stephen Oishi, M.D. prescribes most

Top Medicare Part D drugs by claim count, 2023

claims
Source CMS Medicare Part D Prescriber Public Use File As of 2023
Drug Claims
Atorvastatin Calcium
398
Rosuvastatin Calcium
334
Amlodipine Besylate
278
Losartan Potassium
253
Simvastatin
131
Metformin Hcl
124
Levothyroxine Sodium
120
Telmisartan
120
Lisinopril
105
Farxiga
Dapagliflozin Propanediol
89

* 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 Stephen Oishi, 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

Stephen Oishi, M.D.'s 4,666 claims are above the specialty average of 2,716.

Nearby Internal Medicine Physician Providers in Hawaii

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

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 Hawaii 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.

Frequently Asked Questions

What is Stephen Oishi, M.D.'s specialty?
Stephen Oishi, M.D. specializes in Internal Medicine Physician and practices in Honolulu, Hawaii. Credentials: M.D..
How much does Stephen Oishi, M.D. prescribe under Medicare Part D?
In 2023, Stephen Oishi, M.D. wrote 4,666 Medicare Part D claims totaling $1.0M in drug costs for 422 beneficiaries.
Where is Stephen Oishi, M.D. located?
Stephen Oishi, M.D. is located at 321 N KUAKINI ST, Honolulu, HI, 96817. Phone: (808) 523-8611.
What is Stephen Oishi, M.D.'s NPI number?
Stephen Oishi, M.D.'s National Provider Identifier (NPI) is 1194813832, issued on 10/10/2006.
Does Stephen Oishi, M.D. prescribe more brand-name or generic drugs?
Stephen Oishi, M.D.'s prescribing is 16% brand-name and 83% generic drugs by claim count, with $883K in brand drug costs.
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 Stephen Oishi, M.D. prescribe most often?
Based on 2023 Medicare Part D data, Stephen Oishi, M.D.'s most frequently prescribed drugs include Atorvastatin Calcium, Rosuvastatin Calcium, Amlodipine Besylate. This reflects Medicare Part D prescriptions only and does not include commercial insurance or other payer types.
Does Stephen Oishi, M.D. accept Medicare?
Stephen Oishi, M.D. appears in CMS Medicare data with 4,666 Part D claims and 422 Medicare beneficiaries in 2023. Contact the provider's office directly to confirm current Medicare enrollment and accepted plans.
How can I verify Stephen Oishi, M.D.'s credentials?
Stephen Oishi, M.D.'s NPI is 1194813832 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

Compiled from official public sources by the PlainDoctor editorial team.