NPI registry status
Active
2026 NPPES data Critical Care Medicine (Internal Medicine) Physician NPI 1689109423
Verify on CMS → Kathryn Libby
Critical Care Medicine (Internal Medicine) Physician in South Portland, Maine.
This profile is drawn from the federal National Provider Identifier Registry (CMS NPPES), which lists more than 7 million U.S. healthcare providers - including 6,646 in Critical Care Medicine (Internal Medicine) 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
47
Medicare Part D claims · 13 beneficiaries · Critical Care Medicine (Internal Medicine) Physician avg: 1K
Generic prescribing
55%
generic claims · 45% brand-name · higher generic rates reduce patient out-of-pocket costs
Source: CMS Medicare Part D Prescriber Public Use File, 2023
Compiled from official public sources by the PlainDoctor editorial team.
What the federal data shows
Kathryn Libby filed 47 Medicare Part D claims in 2023 as a Critical Care Medicine (Internal Medicine) Physician in South Portland, Maine, prescribing 55% generic.
- 47
- Part D claims, 2023
- 55%
- generic prescribing
- Likely
- board-certified (heuristic)
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.
Kathryn Libby's Medicare Part D volume vs every U.S. prescriber
Total Medicare Part D claims, 2023, across all CMS prescribers nationally
47 0th percentile higher than 0% of 1,370,886 prescribers
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 certification likely (heuristic, not verified)
Kathryn Libby practices in an ABMS-board-eligible specialty and shows active CMS Medicare participation + 3 hospital affiliations - signals consistent with board-certified status. For verified board certification, see CertificationMatters.org (the official ABMS public lookup).
What does the federal data show about Kathryn Libby?
Quality data not reportedPrimary specialty
Critical Care Medicine (Internal Medicine) Physician
Medicare Part D claims
47 96% vs specialty avg
Specialty distribution in Maine
How Critical Care Medicine (Internal Medicine) Physician compares to other specialties among Maine 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 Critical Care Medicine (Internal Medicine) Physician. Verify directly:
How MIPS and board certification work
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).
Kathryn Libby appears in the CMS NPPES registry as a Critical Care Medicine (Internal Medicine) Physician provider at 100 FODEN RD STE 103, South Portland, ME, 04106, with a listed phone of (207) 828-1122. NPI 1689109423 was issued on 05/01/2017.
Medicare Part D records for calendar year 2023 show 47 prescription claims written by this provider, covering 13 Medicare beneficiaries and totaling roughly $22K in drug spend, split 45% brand-name and 55% generic by claim count.
Critical Care Medicine (Internal Medicine) Physician is a mid-sized specialty nationwide, with 6,646 enrolled providers across 53 states and an average of 1,069 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
Provider Details
| NPI | 1689109423 |
|---|---|
| Specialty | Critical Care Medicine (Internal Medicine) Physician |
| Gender | Female |
| NPI Issued | 05/01/2017 |
Hospital and facility affiliations
Facilities where Kathryn Libby 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.
According to CMS billing records, Kathryn Libby is affiliated with 3 Medicare-billing facilities.
Chest Medicine Associates PA
South Portland, ME
Mainehealth
Livermore Falls, ME
Mercy Hospital
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 · Above average
Kathryn Libby - brand share 45.0%
Critical Care Medicine (Internal Medicine) Physician average
45% brand-name claims vs 55% generic, on 47 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.
47
Total Claims
$22K
Total Drug Cost
13
Medicare Beneficiaries
Prescribing Breakdown
- 30-Day Fills
- 61
- Total Day Supply
- 1,752
- Brand vs Generic
- 45% brand / 55% generic
- Brand Drug Cost
- $14K
- Generic Drug Cost
- $8K
Patient Demographics
- Average Patient Age
- 62.7 years
- Avg HCC Risk Score
- 2.02
Top Prescribed Drugs (Medicare Part D)
Top drugs by claim count for calendar year 2023. Based on Medicare Part D data only.
| Drug | Claims |
|---|---|
| Trelegy Ellipta Fluticasone/Umeclidin/Vilanter | 13 |
| Montelukast Sodium | 11 |
* Counts below 11 are suppressed by CMS for patient privacy. Generic names shown where available from CMS Part D data.
More Critical Care Medicine (Internal Medicine) Physician in ME →
All providers in Maine →
Compare specialties →
Critical Care Medicine (Internal Medicine) Physician Overview
How Kathryn Libby fits within the Critical Care Medicine (Internal Medicine) Physician landscape nationally.
6,646
Critical Care Medicine (Internal Medicine) Physician Providers in US
53
States with Critical Care Medicine (Internal Medicine) Physician
1,069
Avg Claims per Provider
Kathryn Libby's 47 claims are below the specialty average of 1,069.
Nearby Critical Care Medicine (Internal Medicine) Physician Providers in Maine
Other clinicians with the same primary specialty enrolled in Maine, drawn from the same CMS NPPES roster as Libby.
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 Maine medical board, federal registration is not a license check. Credential verification guide
- Weigh a second option: compare this provider with a nearby Critical Care Medicine (Internal Medicine) 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.
Healthcare Guides
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Medical Specialties Explained
Who treats what and how specialties differ
Understanding Medicare Claims Data
What prescribing data reveals about a provider
In-Network vs Out-of-Network
How insurance networks affect your costs
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Frequently Asked Questions
What is Kathryn Libby's specialty? ▼
Kathryn Libby specializes in Critical Care Medicine (Internal Medicine) Physician and practices in South Portland, Maine.
How much does Kathryn Libby prescribe under Medicare Part D? ▼
In 2023, Kathryn Libby wrote 47 Medicare Part D claims totaling $22K in drug costs for 13 beneficiaries.
Where is Kathryn Libby located? ▼
Kathryn Libby is located at 100 FODEN RD STE 103, South Portland, ME, 04106. Phone: (207) 828-1122.
What is Kathryn Libby's NPI number? ▼
Kathryn Libby's National Provider Identifier (NPI) is 1689109423, issued on 05/01/2017.
Does Kathryn Libby prescribe more brand-name or generic drugs? ▼
Kathryn Libby's prescribing is 45% brand-name and 55% generic drugs by claim count, with $14K in brand drug costs.
How many Critical Care Medicine (Internal Medicine) Physician providers are there in the US? ▼
There are 6,646 Critical Care Medicine (Internal Medicine) Physician providers across 53 states in the US. The average Critical Care Medicine (Internal Medicine) Physician provider writes 1,069 Medicare Part D claims per year.
What drugs does Kathryn Libby prescribe most often? ▼
Based on 2023 Medicare Part D data, Kathryn Libby's most frequently prescribed drugs include Trelegy Ellipta, Montelukast Sodium. This reflects Medicare Part D prescriptions only and does not include commercial insurance or other payer types.
Does Kathryn Libby accept Medicare? ▼
Kathryn Libby appears in CMS Medicare data with 47 Part D claims and 13 Medicare beneficiaries in 2023. Contact the provider's office directly to confirm current Medicare enrollment and accepted plans.
How can I verify Kathryn Libby's credentials? ▼
Kathryn Libby's NPI is 1689109423. 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
View source datasets and methodology notes
- 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.
Every figure on PlainDoctor is rendered directly from the federal CMS NPPES registry, Medicare Part D, MIPS, and Open Payments records, no number is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of May 2026.