2026 NPPES data Internal Medicine Physician NPI 1659509149 M.D.
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ISAAC BERG, M.D.

Internal Medicine Physician in GRAND ISLAND, Nebraska. 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
15K
Medicare Part D claims · 752 beneficiaries · Internal Medicine Physician avg: 3K
Generic prescribing
87%
generic claims · 13% brand-name · higher generic rates reduce patient out-of-pocket costs
What the federal data reveals: ISAAC BERG, M.D. is a Internal Medicine Physician ([object Object]) practicing in GRAND ISLAND, Nebraska with a Medicare Part D prescribing footprint of 15K claims across 752 beneficiaries — 13% brand-name prescribing .

What stands out: ISAAC BERG, M.D. filed 14,895 Medicare Part D claims in 2023 across GRAND ISLAND, Nebraska. Every figure on this page comes straight from federal CMS records, with no proprietary rating applied.

Board certification likely (heuristic — not verified)

ISAAC BERG, 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).

ISAAC BERG, M.D. at a glance

Quality data not reported

NPI registry status

Active

Issued 06/23/2009

NPI 1659509149

Primary specialty

Internal Medicine Physician

High-volume

172,858 US NPIs in this specialty

Medicare Part D claims

14,895 448% vs specialty avg

2023 prescription claims

Specialty avg: 2,716

Specialty distribution in Nebraska

How Internal Medicine Physician compares to other specialties among Nebraska providers

Nebraska providers

Internal Medicine Physician share within Nebraska

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

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).

ISAAC BERG, M.D. is a Internal Medicine Physician provider practicing in GRAND ISLAND, Nebraska, according to the CMS National Plan and Provider Enumeration System (NPPES). Credentials: M.D.. NPI: 1659509149. 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.

ISAAC BERG, M.D. appears in the CMS NPPES registry as a Internal Medicine Physician provider holding M.D. credentials at 729 N CUSTER AVE, GRAND ISLAND, NE, 68803, with a listed phone of (308) 382-9266. NPI 1659509149 was issued on 06/23/2009. Because NPPES data is self-reported by the provider and refreshed monthly, the address, phone, and specialty reflect what BERG 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 14,895 prescription claims written by this provider, covering 752 Medicare beneficiaries and totaling roughly $1.5 million in drug spend, split 13% brand-name and 87% generic by claim count, with an opioid prescribing rate of 2.5%. 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.

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

729 N CUSTER AVE
GRAND ISLAND, NE 68803

Provider Details

NPI 1659509149
Specialty Internal Medicine Physician
Credentials M.D.
Gender Male
NPI Issued 06/23/2009

Hospital and facility affiliations

Facilities where ISAAC BERG, 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.

UNMC PHYSICIANS
GRAND ISLAND, NE

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

Brand vs generic prescribing mix · Typical

ISAAC BERG, M.D. — brand share 13.0%
Specialty average (est.)

13% brand-name claims vs 87% generic, on 14,895 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.

14,895
Total Claims
$1.5M
Total Drug Cost
752
Medicare Beneficiaries

Prescribing Breakdown

30-Day Fills
27,349
Total Day Supply
751,709
Brand vs Generic
13% brand / 87% generic
Brand Drug Cost
$1.2M
Generic Drug Cost
$308K
Opioid Claims
374 (2.5% rate)
Antibiotic Claims
284

Patient Demographics

Average Patient Age
74.6 years
Avg HCC Risk Score
1.40
Gender Split
61% female / 39% male
Age Distribution
<65: 60, 65-74: 326, 75-84: 238, 85+: 128

Top Prescribed Drugs (Medicare Part D)

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

Drug Claims
Atorvastatin Calcium
676
Pantoprazole Sodium
453
Levothyroxine Sodium
441
Omeprazole
382
Losartan Potassium
358
Potassium Chloride
357
Furosemide
356
Amlodipine Besylate
333
Tamsulosin Hcl
331
Simvastatin
322

* 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 ISAAC BERG, 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

ISAAC BERG, M.D.'s 14,895 claims are above the specialty average of 2,716.

Nearby Internal Medicine Physician Providers in Nebraska

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

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

Frequently Asked Questions

What is ISAAC BERG, M.D.'s specialty?
ISAAC BERG, M.D. specializes in Internal Medicine Physician and practices in GRAND ISLAND, Nebraska. Credentials: M.D..
How much does ISAAC BERG, M.D. prescribe under Medicare Part D?
In 2023, ISAAC BERG, M.D. wrote 14,895 Medicare Part D claims totaling $1.5M in drug costs for 752 beneficiaries.
Where is ISAAC BERG, M.D. located?
ISAAC BERG, M.D. is located at 729 N CUSTER AVE, GRAND ISLAND, NE, 68803. Phone: (308) 382-9266.
What is ISAAC BERG, M.D.'s NPI number?
ISAAC BERG, M.D.'s National Provider Identifier (NPI) is 1659509149, issued on 06/23/2009.
Does ISAAC BERG, M.D. prescribe more brand-name or generic drugs?
ISAAC BERG, M.D.'s prescribing is 13% brand-name and 87% generic drugs by claim count, with $1.2M in brand drug costs.
Does ISAAC BERG, M.D. prescribe opioids?
Yes, ISAAC BERG, M.D. had 374 opioid claims in 2023 with an opioid prescribing rate of 2.5%.
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 ISAAC BERG, M.D. prescribe most often?
Based on 2023 Medicare Part D data, ISAAC BERG, M.D.'s most frequently prescribed drugs include Atorvastatin Calcium, Pantoprazole Sodium, Levothyroxine Sodium. This reflects Medicare Part D prescriptions only and does not include commercial insurance or other payer types.
Does ISAAC BERG, M.D. accept Medicare?
ISAAC BERG, M.D. appears in CMS Medicare data with 14,895 Part D claims and 752 Medicare beneficiaries in 2023. Contact the provider's office directly to confirm current Medicare enrollment and accepted plans.
How can I verify ISAAC BERG, M.D.'s credentials?
ISAAC BERG, M.D.'s NPI is 1659509149 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