2026 NPPES data Internal Medicine Physician NPI 1023042603 M.D.
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JOSEPH KAMAKA, M.D.

Internal Medicine Physician in WAILUKU, Hawaii. 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
3K
Medicare Part D claims · 156 beneficiaries · Internal Medicine Physician avg: 3K
Generic prescribing
90%
generic claims · 10% brand-name · higher generic rates reduce patient out-of-pocket costs
Industry payments
$24.69
1 payments · CMS Open Payments (Sunshine Act)

What the federal data shows

JOSEPH KAMAKA, M.D. filed 2,990 Medicare Part D claims in 2023 as a Internal Medicine Physician in WAILUKU, Hawaii, prescribing 90% generic.

3K
Part D claims, 2023
90%
generic prescribing
$24.69
industry payments (Sunshine Act)

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

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

2,990 Top 12% higher than 88% 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. 2,000–2,200: 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-eligible specialty (heuristic — not verified)

JOSEPH KAMAKA, 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 KAMAKA, M.D.?

Quality data not reported

NPI registry status

Active

Issued 07/10/2006

NPI 1023042603

Primary specialty

Internal Medicine Physician

High-volume

172,858 US NPIs in this specialty

Medicare Part D claims

2,990 10% 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

Internal Medicine Physician share within Hawaii

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

Specialty board-certification context

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

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

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

0%100%78%
Est. board-certified rate (Internal Medicine 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).

JOSEPH KAMAKA, M.D. appears in the CMS NPPES registry as a Internal Medicine Physician provider holding M.D. credentials at 99 SOUTH MARKET STREET, WAILUKU, HI, 96793, with a listed phone of (808) 244-5551. NPI 1023042603 was issued on 07/10/2006. Because NPPES data is self-reported by the provider and refreshed monthly, the address, phone, and specialty reflect what KAMAKA 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 2,990 prescription claims written by this provider, covering 156 Medicare beneficiaries and totaling roughly $394K in drug spend, split 10% brand-name and 90% generic by claim count, with an opioid prescribing rate of 10.0%. 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

99 SOUTH MARKET STREET
WAILUKU, HI 96793

Provider Details

NPI 1023042603
Specialty Internal Medicine Physician
Credentials M.D.
Gender Male
NPI Issued 07/10/2006

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 JOSEPH KAMAKA, M.D.. Source: openpaymentsdata.cms.gov.

Total received

$25

Largest payer

Lilly USA, LLC

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

JOSEPH KAMAKA, M.D. — brand share 10.0%
Specialty average (est.)

10% brand-name claims vs 90% generic, on 2,990 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.

2,990
Total Claims
$394K
Total Drug Cost
156
Medicare Beneficiaries

Prescribing Breakdown

30-Day Fills
6,732
Total Day Supply
196,110
Brand vs Generic
10% brand / 90% generic
Brand Drug Cost
$321K
Generic Drug Cost
$72K
Opioid Claims
299 (10.0% rate)
Antibiotic Claims
31

Patient Demographics

Average Patient Age
70.8 years
Avg HCC Risk Score
1.09
Gender Split
40% female / 60% male

Top Prescribed Drugs (Medicare Part D)

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

What JOSEPH KAMAKA, 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
227
Hydrocodone-Acetaminophen
Hydrocodone/Acetaminophen
226
Lisinopril
185
Metoprolol Succinate
158
Rosuvastatin Calcium
91
Amlodipine Besylate
90
Pioglitazone Hcl
81
Ibuprofen
69
Allopurinol
62
Albuterol Sulfate Hfa
Albuterol Sulfate
60

* 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 JOSEPH KAMAKA, 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

JOSEPH KAMAKA, M.D.'s 2,990 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 KAMAKA.

Compare Internal Medicine Physician nationally: see state-by-state distribution →

Frequently Asked Questions

What is JOSEPH KAMAKA, M.D.'s specialty?
JOSEPH KAMAKA, M.D. specializes in Internal Medicine Physician and practices in WAILUKU, Hawaii. Credentials: M.D..
How much does JOSEPH KAMAKA, M.D. prescribe under Medicare Part D?
In 2023, JOSEPH KAMAKA, M.D. wrote 2,990 Medicare Part D claims totaling $394K in drug costs for 156 beneficiaries.
Where is JOSEPH KAMAKA, M.D. located?
JOSEPH KAMAKA, M.D. is located at 99 SOUTH MARKET STREET, WAILUKU, HI, 96793. Phone: (808) 244-5551.
What is JOSEPH KAMAKA, M.D.'s NPI number?
JOSEPH KAMAKA, M.D.'s National Provider Identifier (NPI) is 1023042603, issued on 07/10/2006.
Does JOSEPH KAMAKA, M.D. prescribe more brand-name or generic drugs?
JOSEPH KAMAKA, M.D.'s prescribing is 10% brand-name and 90% generic drugs by claim count, with $321K in brand drug costs.
Does JOSEPH KAMAKA, M.D. prescribe opioids?
Yes, JOSEPH KAMAKA, M.D. had 299 opioid claims in 2023 with an opioid prescribing rate of 10.0%.
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 JOSEPH KAMAKA, M.D. prescribe most often?
Based on 2023 Medicare Part D data, JOSEPH KAMAKA, M.D.'s most frequently prescribed drugs include Atorvastatin Calcium, Hydrocodone-Acetaminophen, Lisinopril. This reflects Medicare Part D prescriptions only and does not include commercial insurance or other payer types.
Does JOSEPH KAMAKA, M.D. accept Medicare?
JOSEPH KAMAKA, M.D. appears in CMS Medicare data with 2,990 Part D claims and 156 Medicare beneficiaries in 2023. Contact the provider's office directly to confirm current Medicare enrollment and accepted plans.
How can I verify JOSEPH KAMAKA, M.D.'s credentials?
JOSEPH KAMAKA, M.D.'s NPI is 1023042603 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