2026 NPPES data Geriatric Medicine (Internal Medicine) Physician NPI 1295921773 M.D.
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ISAO IWATA, M.D.

Geriatric Medicine (Internal Medicine) Physician in PLAINSBORO, New Jersey. 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
5K
Medicare Part D claims · 438 beneficiaries · Geriatric Medicine (Internal Medicine) Physician avg: 4K
Generic prescribing
91%
generic claims · 9% brand-name · higher generic rates reduce patient out-of-pocket costs

What the federal data shows

ISAO IWATA, M.D. filed 4,578 Medicare Part D claims in 2023 as a Geriatric Medicine (Internal Medicine) Physician in PLAINSBORO, New Jersey, prescribing 91% generic.

5K
Part D claims, 2023
91%
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.

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

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

4,578 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. 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)

ISAO IWATA, 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 ISAO IWATA, M.D.?

Quality data not reported

NPI registry status

Active

Issued 09/19/2007

NPI 1295921773

Primary specialty

Geriatric Medicine (Internal Medicine) Physician

Niche

4,161 US NPIs in this specialty

Medicare Part D claims

4,578 3% vs specialty avg

2023 prescription claims

Specialty avg: 4,450

Specialty distribution in New Jersey

How Geriatric Medicine (Internal Medicine) Physician compares to other specialties among New Jersey providers

New Jersey providers

Geriatric Medicine (Internal Medicine) Physician share within New Jersey

1. Geriatric Medicine (Internal Medicine) Physician42%2. Internal medicine21%3. Family medicine17%4. Surgical12%5. Pediatric8%
Geriatric Medicine (Internal Medicine) Physician share within New Jersey

Specialty board-certification context

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

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

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

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

ISAO IWATA, M.D. appears in the CMS NPPES registry as a Geriatric Medicine (Internal Medicine) Physician provider holding M.D. credentials at 5 PLAINSBORO RD STE 300, PLAINSBORO, NJ, 08536, with a listed phone of (609) 853-7272. NPI 1295921773 was issued on 09/19/2007. Because NPPES data is self-reported by the provider and refreshed monthly, the address, phone, and specialty reflect what IWATA 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 4,578 prescription claims written by this provider, covering 438 Medicare beneficiaries and totaling roughly $379K in drug spend, split 9% brand-name and 91% generic by claim count, with an opioid prescribing rate of 0.5%. 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.

Geriatric Medicine (Internal Medicine) Physician is a narrow specialty nationwide, with 4,161 enrolled providers across 52 states and an average of 4,450 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

5 PLAINSBORO RD STE 300
PLAINSBORO, NJ 08536

Provider Details

NPI 1295921773
Specialty Geriatric Medicine (Internal Medicine) Physician
Credentials M.D.
Gender Male
NPI Issued 09/19/2007

Brand vs generic prescribing mix · Generic-heavy

ISAO IWATA, M.D. — brand share 9.0%
Specialty average (est.)

9% brand-name claims vs 91% generic, on 4,578 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.

4,578
Total Claims
$379K
Total Drug Cost
438
Medicare Beneficiaries

Prescribing Breakdown

30-Day Fills
10,302
Total Day Supply
302,817
Brand vs Generic
9% brand / 91% generic
Brand Drug Cost
$275K
Generic Drug Cost
$102K
Opioid Claims
22 (0.5% rate)
Antibiotic Claims
59

Patient Demographics

Average Patient Age
77.2 years
Avg HCC Risk Score
1.35
Gender Split
48% female / 52% male
Age Distribution
<65: 16, 65-74: 158, 75-84: 166, 85+: 98

Top Prescribed Drugs (Medicare Part D)

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

What ISAO IWATA, 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
392
Rosuvastatin Calcium
254
Amlodipine Besylate
224
Levothyroxine Sodium
182
Losartan Potassium
138
Omeprazole
136
Hydrochlorothiazide
115
Lisinopril
103
Metformin Hcl
97
Tamsulosin Hcl
87

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

Geriatric Medicine (Internal Medicine) Physician Overview

How ISAO IWATA, M.D. fits within the Geriatric Medicine (Internal Medicine) Physician landscape nationally.

4,161
Geriatric Medicine (Internal Medicine) Physician Providers in US
52
States with Geriatric Medicine (Internal Medicine) Physician
4,450
Avg Claims per Provider

ISAO IWATA, M.D.'s 4,578 claims are above the specialty average of 4,450.

Nearby Geriatric Medicine (Internal Medicine) Physician Providers in New Jersey

Other clinicians with the same primary specialty enrolled in New Jersey, drawn from the same CMS NPPES roster as IWATA.

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

Frequently Asked Questions

What is ISAO IWATA, M.D.'s specialty?
ISAO IWATA, M.D. specializes in Geriatric Medicine (Internal Medicine) Physician and practices in PLAINSBORO, New Jersey. Credentials: M.D..
How much does ISAO IWATA, M.D. prescribe under Medicare Part D?
In 2023, ISAO IWATA, M.D. wrote 4,578 Medicare Part D claims totaling $379K in drug costs for 438 beneficiaries.
Where is ISAO IWATA, M.D. located?
ISAO IWATA, M.D. is located at 5 PLAINSBORO RD STE 300, PLAINSBORO, NJ, 08536. Phone: (609) 853-7272.
What is ISAO IWATA, M.D.'s NPI number?
ISAO IWATA, M.D.'s National Provider Identifier (NPI) is 1295921773, issued on 09/19/2007.
Does ISAO IWATA, M.D. prescribe more brand-name or generic drugs?
ISAO IWATA, M.D.'s prescribing is 9% brand-name and 91% generic drugs by claim count, with $275K in brand drug costs.
Does ISAO IWATA, M.D. prescribe opioids?
Yes, ISAO IWATA, M.D. had 22 opioid claims in 2023 with an opioid prescribing rate of 0.5%.
How many Geriatric Medicine (Internal Medicine) Physician providers are there in the US?
There are 4,161 Geriatric Medicine (Internal Medicine) Physician providers across 52 states in the US. The average Geriatric Medicine (Internal Medicine) Physician provider writes 4,450 Medicare Part D claims per year.
What drugs does ISAO IWATA, M.D. prescribe most often?
Based on 2023 Medicare Part D data, ISAO IWATA, 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 ISAO IWATA, M.D. accept Medicare?
ISAO IWATA, M.D. appears in CMS Medicare data with 4,578 Part D claims and 438 Medicare beneficiaries in 2023. Contact the provider's office directly to confirm current Medicare enrollment and accepted plans.
How can I verify ISAO IWATA, M.D.'s credentials?
ISAO IWATA, M.D.'s NPI is 1295921773 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