2026 NPPES data Internal Medicine Physician NPI 1821257650 DO
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CATHERINE FREDRICKS-REHAGEN, DO

Internal Medicine Physician in BATH, Maine. 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
7K
Medicare Part D claims · 600 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: CATHERINE FREDRICKS-REHAGEN, DO is a Internal Medicine Physician ([object Object]) practicing in BATH, Maine with a Medicare Part D prescribing footprint of 7K claims across 600 beneficiaries — 13% brand-name prescribing .

What stands out: CATHERINE FREDRICKS-REHAGEN, DO filed 7,239 Medicare Part D claims in 2023 across BATH, Maine. Every figure on this page comes straight from federal CMS records, with no proprietary rating applied.

Board certification likely (heuristic — not verified)

CATHERINE FREDRICKS-REHAGEN, DO 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).

CATHERINE FREDRICKS-REHAGEN, DO at a glance

Quality data not reported

NPI registry status

Active

Issued 06/06/2008

NPI 1821257650

Primary specialty

Internal Medicine Physician

High-volume

172,858 US NPIs in this specialty

Medicare Part D claims

7,239 167% vs specialty avg

2023 prescription claims

Specialty avg: 2,716

Specialty distribution in Maine

How Internal Medicine Physician compares to other specialties among Maine providers

Maine providers

Internal Medicine Physician share within Maine

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

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).

CATHERINE FREDRICKS-REHAGEN, DO is a Internal Medicine Physician provider practicing in BATH, Maine, according to the CMS National Plan and Provider Enumeration System (NPPES). Credentials: DO. NPI: 1821257650. 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.

CATHERINE FREDRICKS-REHAGEN, DO appears in the CMS NPPES registry as a Internal Medicine Physician provider holding DO credentials at 108 CENTRE ST, BATH, ME, 04530, with a listed phone of (207) 386-1800. NPI 1821257650 was issued on 06/06/2008. Because NPPES data is self-reported by the provider and refreshed monthly, the address, phone, and specialty reflect what FREDRICKS-REHAGEN 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 7,239 prescription claims written by this provider, covering 600 Medicare beneficiaries and totaling roughly $692K in drug spend, split 13% brand-name and 87% generic by claim count, with an opioid prescribing rate of 3.0%. 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

108 CENTRE ST
BATH, ME 04530

Provider Details

NPI 1821257650
Specialty Internal Medicine Physician
Credentials DO
Gender Female
NPI Issued 06/06/2008

Hospital and facility affiliations

Facilities where CATHERINE FREDRICKS-REHAGEN, DO 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.

MAINEHEALTH
PORTLAND, ME

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

CATHERINE FREDRICKS-REHAGEN, DO — brand share 13.0%
Specialty average (est.)

13% brand-name claims vs 87% generic, on 7,239 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.

7,239
Total Claims
$692K
Total Drug Cost
600
Medicare Beneficiaries

Prescribing Breakdown

30-Day Fills
16,335
Total Day Supply
471,479
Brand vs Generic
13% brand / 87% generic
Brand Drug Cost
$532K
Generic Drug Cost
$156K
Opioid Claims
214 (3.0% rate)
Antibiotic Claims
147

Patient Demographics

Average Patient Age
73.5 years
Avg HCC Risk Score
1.01
Gender Split
68% female / 32% male
Age Distribution
<65: 46, 65-74: 292, 75-84: 197, 85+: 65

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
469
Levothyroxine Sodium
378
Lisinopril
308
Losartan Potassium
216
Omeprazole
213
Hydrochlorothiazide
202
Simvastatin
166
Amlodipine Besylate
165
Sertraline Hcl
145
Oxycodone Hcl
137

* 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 CATHERINE FREDRICKS-REHAGEN, DO 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

CATHERINE FREDRICKS-REHAGEN, DO's 7,239 claims are above the specialty average of 2,716.

Nearby Internal Medicine Physician Providers in Maine

Other clinicians with the same primary specialty enrolled in Maine, drawn from the same CMS NPPES roster as FREDRICKS-REHAGEN.

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

Frequently Asked Questions

What is CATHERINE FREDRICKS-REHAGEN, DO's specialty?
CATHERINE FREDRICKS-REHAGEN, DO specializes in Internal Medicine Physician and practices in BATH, Maine. Credentials: DO.
How much does CATHERINE FREDRICKS-REHAGEN, DO prescribe under Medicare Part D?
In 2023, CATHERINE FREDRICKS-REHAGEN, DO wrote 7,239 Medicare Part D claims totaling $692K in drug costs for 600 beneficiaries.
Where is CATHERINE FREDRICKS-REHAGEN, DO located?
CATHERINE FREDRICKS-REHAGEN, DO is located at 108 CENTRE ST, BATH, ME, 04530. Phone: (207) 386-1800.
What is CATHERINE FREDRICKS-REHAGEN, DO's NPI number?
CATHERINE FREDRICKS-REHAGEN, DO's National Provider Identifier (NPI) is 1821257650, issued on 06/06/2008.
Does CATHERINE FREDRICKS-REHAGEN, DO prescribe more brand-name or generic drugs?
CATHERINE FREDRICKS-REHAGEN, DO's prescribing is 13% brand-name and 87% generic drugs by claim count, with $532K in brand drug costs.
Does CATHERINE FREDRICKS-REHAGEN, DO prescribe opioids?
Yes, CATHERINE FREDRICKS-REHAGEN, DO had 214 opioid claims in 2023 with an opioid prescribing rate of 3.0%.
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 CATHERINE FREDRICKS-REHAGEN, DO prescribe most often?
Based on 2023 Medicare Part D data, CATHERINE FREDRICKS-REHAGEN, DO's most frequently prescribed drugs include Atorvastatin Calcium, Levothyroxine Sodium, Lisinopril. This reflects Medicare Part D prescriptions only and does not include commercial insurance or other payer types.
Does CATHERINE FREDRICKS-REHAGEN, DO accept Medicare?
CATHERINE FREDRICKS-REHAGEN, DO appears in CMS Medicare data with 7,239 Part D claims and 600 Medicare beneficiaries in 2023. Contact the provider's office directly to confirm current Medicare enrollment and accepted plans.
How can I verify CATHERINE FREDRICKS-REHAGEN, DO's credentials?
CATHERINE FREDRICKS-REHAGEN, DO's NPI is 1821257650 with credentials DO. 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