2026 NPPES data Infectious Disease Physician NPI 1457350985 M.D.
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Joseph Koo, M.D.

Infectious Disease 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 8,292 in Infectious Disease 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
564
Medicare Part D claims · 117 beneficiaries · Infectious Disease Physician avg: 816
Generic prescribing
94%
generic claims · 6% brand-name · higher generic rates reduce patient out-of-pocket costs
Compiled from official public sources by the PlainDoctor editorial team.

What the federal data shows

Joseph Koo, M.D. filed 564 Medicare Part D claims in 2023 as a Infectious Disease Physician in Honolulu, Hawaii, prescribing 94% generic.

564
Part D claims, 2023
94%
generic prescribing

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.

Joseph Koo, M.D.'s Medicare Part D volume vs every U.S. prescriber

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

564 Top 34% higher than 66% 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%). This entry sits in this band. 600–800: 56,224 prescribers (4%). Above this entry. 800–1,000: 40,919 prescribers (3%). Above this entry. 1,000–1,200: 31,827 prescribers (2%). Above this entry. 1,200–1,400: 26,224 prescribers (2%). Above this entry. 1,400–1,600: 21,710 prescribers (2%). Above this entry. 1,600–1,800: 19,072 prescribers (1%). Above this entry. 1,800–2,000: 16,451 prescribers (1%). Above this entry. 2K+: 213,991 prescribers (16%). Above this entry. 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-eligible specialty (heuristic, not verified)

Joseph Koo, M.D. practices in an ABMS-board-eligible specialty but we don't have enough CMS-participation signals to confirm active board-certified status. Consult CertificationMatters.org (the official ABMS public lookup).

What does the federal data show about Joseph Koo, M.D.?

Quality data not reported

NPI registry status

Active

Issued 07/18/2005

NPI 1457350985

Primary specialty

Infectious Disease Physician

Mid-sized

8,292 US NPIs in this specialty

Medicare Part D claims

564 31% vs specialty avg

2023 prescription claims

Specialty avg: 816

Specialty distribution in Hawaii

How Infectious Disease Physician compares to other specialties among Hawaii providers

Hawaii providers

Largest specialties in Hawaii (% of in-state 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%Infectious Disease Physician - 0.1%Infectious Disease Physician0.1%
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 Infectious Disease 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).

Joseph Koo, M.D. appears in the CMS NPPES registry as a Infectious Disease Physician provider holding M.D. credentials at 321 N. KUAKINI STREET, SUITE 715, Honolulu, HI, 96817, with a listed phone of (808) 523-6461. NPI 1457350985 was issued on 07/18/2005. Because NPPES data is self-reported by the provider and refreshed monthly, the address, phone, and specialty reflect what Koo 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 564 prescription claims written by this provider, covering 117 Medicare beneficiaries and totaling roughly $73K in drug spend, split 6% brand-name and 94% 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.

Infectious Disease Physician is a mid-sized specialty nationwide, with 8,292 enrolled providers across 54 states and an average of 816 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 STREET, SUITE 715
Honolulu, HI 96817

Provider Details

NPI 1457350985
Specialty Infectious Disease Physician
Credentials M.D.
Gender Male
NPI Issued 07/18/2005

Brand vs generic prescribing mix · Generic-heavy

Joseph Koo, M.D. - brand share 6.0%
Infectious Disease Physician average

6% brand-name claims vs 94% generic, on 564 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.

564
Total Claims
$73K
Total Drug Cost
117
Medicare Beneficiaries

Prescribing Breakdown

30-Day Fills
919
Total Day Supply
24,604
Brand vs Generic
6% brand / 94% generic
Brand Drug Cost
$23K
Generic Drug Cost
$50K
Antibiotic Claims
273

Patient Demographics

Average Patient Age
74.9 years
Avg HCC Risk Score
2.35
Gender Split
52% female / 48% male
Age Distribution
<65: 13, 65-74: 40, 75-84: 49, 85+: 15

Top Prescribed Drugs (Medicare Part D)

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

What Joseph Koo, 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
Azithromycin
65
Sulfamethoxazole-Trimethoprim
Sulfamethoxazole/Trimethoprim
24
Doxycycline Hyclate
20
Cefdinir
19
Ciprofloxacin Hcl
19
Triamcinolone Acetonide
19
Vancomycin Hcl
18
Amoxicillin-Clavulanate Potass
Amoxicillin/Potassium Clav
17
Valganciclovir Hcl
17
Fenofibrate
Fenofibrate Nanocrystallized
16

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

Infectious Disease Physician Overview

How Joseph Koo, M.D. fits within the Infectious Disease Physician landscape nationally.

8,292
Infectious Disease Physician Providers in US
54
States with Infectious Disease Physician
816
Avg Claims per Provider

Joseph Koo, M.D.'s 564 claims are below the specialty average of 816.

Nearby Infectious Disease Physician Providers in Hawaii

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

Compare Infectious Disease 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 Infectious Disease 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 Joseph Koo, M.D.'s specialty?
Joseph Koo, M.D. specializes in Infectious Disease Physician and practices in Honolulu, Hawaii. Credentials: M.D..
How much does Joseph Koo, M.D. prescribe under Medicare Part D?
In 2023, Joseph Koo, M.D. wrote 564 Medicare Part D claims totaling $73K in drug costs for 117 beneficiaries.
Where is Joseph Koo, M.D. located?
Joseph Koo, M.D. is located at 321 N. KUAKINI STREET, SUITE 715, Honolulu, HI, 96817. Phone: (808) 523-6461.
What is Joseph Koo, M.D.'s NPI number?
Joseph Koo, M.D.'s National Provider Identifier (NPI) is 1457350985, issued on 07/18/2005.
Does Joseph Koo, M.D. prescribe more brand-name or generic drugs?
Joseph Koo, M.D.'s prescribing is 6% brand-name and 94% generic drugs by claim count, with $23K in brand drug costs.
How many Infectious Disease Physician providers are there in the US?
There are 8,292 Infectious Disease Physician providers across 54 states in the US. The average Infectious Disease Physician provider writes 816 Medicare Part D claims per year.
What drugs does Joseph Koo, M.D. prescribe most often?
Based on 2023 Medicare Part D data, Joseph Koo, M.D.'s most frequently prescribed drugs include Azithromycin, Sulfamethoxazole-Trimethoprim, Doxycycline Hyclate. This reflects Medicare Part D prescriptions only and does not include commercial insurance or other payer types.
Does Joseph Koo, M.D. accept Medicare?
Joseph Koo, M.D. appears in CMS Medicare data with 564 Part D claims and 117 Medicare beneficiaries in 2023. Contact the provider's office directly to confirm current Medicare enrollment and accepted plans.
How can I verify Joseph Koo, M.D.'s credentials?
Joseph Koo, M.D.'s NPI is 1457350985 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.