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2026 NPPES data Endocrinology, Diabetes & Metabolism Physician NPI 1427009273 MD
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Diana Maas, MD

Endocrinology, Diabetes & Metabolism Physician in Milwaukee, Wisconsin.

This profile is drawn from the federal National Provider Identifier Registry (CMS NPPES), which lists more than 7 million U.S. healthcare providers - including 8,078 in Endocrinology, Diabetes & Metabolism 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
336
Medicare Part D claims · 130 beneficiaries · Endocrinology, Diabetes & Metabolism Physician avg: 3K
Generic prescribing
50%
generic claims · 46% brand-name · higher generic rates reduce patient out-of-pocket costs
MIPS score
80.5/100
▼ 3 pts below national avg 83.5 · Above neutral
Verify NPI on CMS Methodology
Compiled from official public sources by the editorial process.

What the federal data shows

Diana Maas, MD reported a CMS MIPS final score of 80.5/100 - below the 83.5 national average - and filed 336 Medicare Part D claims in 2024.

80.5/100
MIPS score · -3 vs avg
336
Part D claims, 2024
50%
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.

Federal trust snapshot

What official records show about Diana Maas, MD

Federal records show an active NPI with both Medicare prescribing volume and a measured CMS quality score — objective registry data, not patient reviews.

  • Verified

    NPI registry status

    Active listing in the CMS National Provider Identifier Registry (NPI 1427009273), first enumerated 05/15/2006.

    Source: CMS NPPES

  • Reported

    Medicare Part D participation

    Filed 336 Medicare Part D prescription claims in the 2023 CMS public use file — indicates active Medicare prescribing participation.

    Source: CMS Part D Prescriber PUF

  • Reported

    CMS quality reporting (MIPS)

    Reported a CMS MIPS final score of 80.5/100 in the Quality Payment Program — a federal quality measure, not a patient review.

    Source: CMS Quality Payment Program

  • Reported

    Board certification signal

    Heuristic suggests board-certified status based on ABMS-eligible specialty taxonomy plus active CMS participation signals — not a direct ABMS verification.

    Source: NUCC taxonomy + CMS participation heuristic

  • Not in federal data

    Individual sanction lookup

    PlainDoctor does not publish per-provider disciplinary determinations. Confirm current license and any individual actions through the state medical board or FSMB verification service.

    Source: State medical board / FSMB

This trust snapshot summarizes only what appears in federal CMS/NPPES public records. It is not a composite score, star rating, patient review, or clinical recommendation. PlainDoctor never fabricates reviews or AggregateRating schema.

CMS NPPES provider registry desk

NPI 1427009273 · Endocrinology, Diabetes & Metabolism Physician

NPI-10 · ENUM-LEGACY · TAX-MID · MIPS-INLINE · RX-LIGHT · BOOK-THIN · PHOTO-FINISH

  • NPI-10 1427009273
  • ENUM-LEGACY 2006
  • TAX-MID 8K Endocrinology, Diabetes
  • MIPS-INLINE 80.5/100
  • RX-LIGHT 336
  • BOOK-THIN 144 in Wisconsin
  • PHOTO-FINISH Felice Caldarella · ±0.0

MIPS final-score neighbourhood

Same-specialty nationwide peers by CMS final score, not geographic proximity

MIPS pts

What this shows Nearest measured MIPS peers for this NUCC specialty (2023 performance year).

Source CMS Quality Payment Program (MIPS) As of 2023

Diana Maas, MD's MIPS score vs every measured U.S. clinician

CMS Merit-based Incentive Payment System (MIPS) final score, 2023, the federal quality measure. Clinicians whose score CMS assigned without scoring any category are excluded.

81 ≥ 30th percentile 30% of 454,083 measured providers are in lower value bands

0–10: 8,684 measured providers (2%). Below this entry. 10–20: 3,008 measured providers (1%). Below this entry. 20–30: 3,069 measured providers (1%). Below this entry. 30–40: 2,746 measured providers (1%). Below this entry. 40–50: 2,928 measured providers (1%). Below this entry. 50–60: 5,882 measured providers (1%). Below this entry. 60–70: 13,906 measured providers (3%). Below this entry. 70–80: 94,570 measured providers (21%). Below this entry. 80–90: 129,887 measured providers (29%). This entry sits in this band. 90+: 189,403 measured providers (42%). Above this entry. This provider 0 100 every measured MIPS clinician, bucketed by value

Each bar is a band; taller bars hold more measured providers. 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.

The percentile is a conservative whole-score-point band: it counts only measured clinicians in lower score bands. A CMS MIPS metric is not a recommendation or a clinical-quality rating by PlainDoctor. See methodology § corpus placement.

Source CMS Merit-based Incentive Payment System (MIPS) · 2023

Where Diana Maas, MD sits

This provider among endocrinology, diabetes & metabolism physician peers

Across the 2,341 endocrinology, diabetes & metabolism physician providers who report both Medicare Part D prescribing and a MIPS quality score, Diana Maas, MD writes more Part D claims than 12% of them and scores higher on MIPS quality than 31% - placing this provider in the lower-volume, lower-quality quadrant. Volume reflects patient-panel size and specialty, not quality; the two axes are independent.

Lower volume · High qualityHigh volume · High qualityLower volume · Lower qualityHigh volume · Lower quality02550751000255075100Part D claim volume, percentile in specialtyMIPS quality, percentilePoint, Part D claim volume, percentile in specialty: 47 · MIPS quality, percentile: 80Point, Part D claim volume, percentile in specialty: 63 · MIPS quality, percentile: 77Point, Part D claim volume, percentile in specialty: 70 · MIPS quality, percentile: 70Point, Part D claim volume, percentile in specialty: 80 · MIPS quality, percentile: 42Point, Part D claim volume, percentile in specialty: 32 · MIPS quality, percentile: 52Point, Part D claim volume, percentile in specialty: 55 · MIPS quality, percentile: 58Point, Part D claim volume, percentile in specialty: 35 · MIPS quality, percentile: 23Point, Part D claim volume, percentile in specialty: 2 · MIPS quality, percentile: 42Point, Part D claim volume, percentile in specialty: 7 · MIPS quality, percentile: 95Point, Part D claim volume, percentile in specialty: 12 · MIPS quality, percentile: 23Point, Part D claim volume, percentile in specialty: 85 · MIPS quality, percentile: 32Point, Part D claim volume, percentile in specialty: 97 · MIPS quality, percentile: 67Point, Part D claim volume, percentile in specialty: 22 · MIPS quality, percentile: 87Point, Part D claim volume, percentile in specialty: 48 · MIPS quality, percentile: 3Point, Part D claim volume, percentile in specialty: 65 · MIPS quality, percentile: 35Point, Part D claim volume, percentile in specialty: 38 · MIPS quality, percentile: 48Point, Part D claim volume, percentile in specialty: 87 · MIPS quality, percentile: 78Point, Part D claim volume, percentile in specialty: 25 · MIPS quality, percentile: 13Point, Part D claim volume, percentile in specialty: 23 · MIPS quality, percentile: 92Point, Part D claim volume, percentile in specialty: 0 · MIPS quality, percentile: 98Point, Part D claim volume, percentile in specialty: 52 · MIPS quality, percentile: 12Point, Part D claim volume, percentile in specialty: 83 · MIPS quality, percentile: 22Point, Part D claim volume, percentile in specialty: 15 · MIPS quality, percentile: 98Point, Part D claim volume, percentile in specialty: 92 · MIPS quality, percentile: 68Point, Part D claim volume, percentile in specialty: 30 · MIPS quality, percentile: 93Point, Part D claim volume, percentile in specialty: 53 · MIPS quality, percentile: 90Point, Part D claim volume, percentile in specialty: 40 · MIPS quality, percentile: 7Point, Part D claim volume, percentile in specialty: 57 · MIPS quality, percentile: 62Point, Part D claim volume, percentile in specialty: 3 · MIPS quality, percentile: 20Point, Part D claim volume, percentile in specialty: 43 · MIPS quality, percentile: 5Point, Part D claim volume, percentile in specialty: 58 · MIPS quality, percentile: 50Point, Part D claim volume, percentile in specialty: 27 · MIPS quality, percentile: 55Point, Part D claim volume, percentile in specialty: 77 · MIPS quality, percentile: 33Point, Part D claim volume, percentile in specialty: 60 · MIPS quality, percentile: 73Point, Part D claim volume, percentile in specialty: 62 · MIPS quality, percentile: 47Point, Part D claim volume, percentile in specialty: 42 · MIPS quality, percentile: 83Point, Part D claim volume, percentile in specialty: 33 · MIPS quality, percentile: 40Point, Part D claim volume, percentile in specialty: 98 · MIPS quality, percentile: 57Point, Part D claim volume, percentile in specialty: 73 · MIPS quality, percentile: 83Point, Part D claim volume, percentile in specialty: 88 · MIPS quality, percentile: 72Point, Part D claim volume, percentile in specialty: 10 · MIPS quality, percentile: 18Point, Part D claim volume, percentile in specialty: 100 · MIPS quality, percentile: 97Point, Part D claim volume, percentile in specialty: 93 · MIPS quality, percentile: 28Point, Part D claim volume, percentile in specialty: 45 · MIPS quality, percentile: 65Point, Part D claim volume, percentile in specialty: 5 · MIPS quality, percentile: 38Point, Part D claim volume, percentile in specialty: 68 · MIPS quality, percentile: 27Point, Part D claim volume, percentile in specialty: 72 · MIPS quality, percentile: 80Point, Part D claim volume, percentile in specialty: 95 · MIPS quality, percentile: 10Point, Part D claim volume, percentile in specialty: 67 · MIPS quality, percentile: 30Point, Part D claim volume, percentile in specialty: 20 · MIPS quality, percentile: 88Point, Part D claim volume, percentile in specialty: 75 · MIPS quality, percentile: 45Point, Part D claim volume, percentile in specialty: 50 · MIPS quality, percentile: 63Point, Part D claim volume, percentile in specialty: 82 · MIPS quality, percentile: 53Point, Part D claim volume, percentile in specialty: 90 · MIPS quality, percentile: 75Point, Part D claim volume, percentile in specialty: 18 · MIPS quality, percentile: 0Point, Part D claim volume, percentile in specialty: 78 · MIPS quality, percentile: 2Point, Part D claim volume, percentile in specialty: 37 · MIPS quality, percentile: 60Point, Part D claim volume, percentile in specialty: 8 · MIPS quality, percentile: 17Point, Part D claim volume, percentile in specialty: 28 · MIPS quality, percentile: 8Point, Part D claim volume, percentile in specialty: 17 · MIPS quality, percentile: 15Diana Maas, MD, Part D claim volume, percentile in specialty: 12 · MIPS quality, percentile: 31
Part D claim volume vs MIPS quality, by specialty percentile

Each dot is one endocrinology, diabetes & metabolism physician peer from a representative sample of 60; the gold marker is Diana Maas, MD. Source: CMS Medicare Part D Prescriber data and the CMS Merit-based Incentive Payment System, 2023.

✓
Board certification likely (heuristic, not verified)

Diana Maas, MD practices in an ABMS-board-eligible specialty and shows active CMS Medicare participation + MIPS quality reporting - 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 Diana Maas, MD?

Near national average

NPI registry status

Active

Issued 05/15/2006

NPI 1427009273

Primary specialty

Endocrinology, Diabetes & Metabolism Physician

Mid-sized

8,078 US NPIs in this specialty

Medicare Part D claims

336 88% vs specialty avg

2024 prescription claims

Specialty avg: 2,739

MIPS final score

80.5/100 3 pts vs avg

Above neutral band

vs 83.5 national avg

Specialty distribution in Wisconsin

How Endocrinology, Diabetes & Metabolism Physician compares to other specialties among Wisconsin providers

Wisconsin providers
Physical Therapist5.5%Registered Nurse4.7%Pharmacist4.6%Student in an Organized Heal…3.4%Professional Counselor3.3%Speech-Language Pathologist3.2%Endocrinology, Diabetes & Me…0.1%
Largest specialties in Wisconsin (% of in-state providers)

Medicare quality performance, MIPS

Diana Maas, MD's 2023 MIPS final score plotted against the Endocrinology, Diabetes & Metabolism Physician national average

Near national average
MIPS Final Score
80.5/100
vs 83.5 national avg · 2023 performance year
0%100%National avg84%80.5%
MIPS final score (Endocrinology, Diabetes & Metabolism Physician) - 80.5/100 vs national avg 83.5
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).

Practice Address

FROEDTERT & MED COLLEGE CLIN - EAST
Milwaukee, WI 53226
(414) 805-3666

Provider Details

NPI 1427009273
Specialty Endocrinology, Diabetes & Metabolism Physician
Credentials MD
Gender Female
NPI Issued 05/15/2006

CMS Quality Score (MIPS)

Merit-based Incentive Payment System (MIPS) scores from CMS, 2023 performance year.

80.4671
Final Score
Measured-score avg: 83.5
66.2426
Quality
68.6477
Cost
100
Promoting Interoperability

Reporting: Group practice

Brand vs generic prescribing mix · Above average

Diana Maas, MD - brand share 46.0%
Endocrinology, Diabetes & Metabolism Physician average

46% brand-name claims vs 50% generic, on 336 2024 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 2024.

336
Total Claims
$23K
Total Drug Cost
130
Medicare Beneficiaries

Prescribing Breakdown

30-Day Fills
822.7
Total Day Supply
24,142
Brand vs Generic
46% brand / 50% generic
Brand Drug Cost
$12K
Generic Drug Cost
$7K

Patient Demographics

Average Patient Age
69.8 years
Avg HCC Risk Score
1.31
Gender Split
75% female / 25% male
Age Distribution
<65: 22, 65-74: 61, 75-84: N/A, 85+: N/A

Top Prescribed Drugs (Medicare Part D)

Top drugs by claim count for calendar year 2024. Based on Medicare Part D data only.

What Diana Maas, MD prescribes most

Top Medicare Part D drugs by claim count, 2024

claims
Source CMS Medicare Part D Prescriber Public Use File As of 2024
Drug Claims
Levothyroxine Sodium
 105
Hydrocortisone
 51
Synthroid
Levothyroxine Sodium
51
Cabergoline
 12
Fludrocortisone Acetate
 11

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

More Endocrinology, Diabetes & Metabolism Physician in WI → All providers in Wisconsin → Compare specialties →

Endocrinology, Diabetes & Metabolism Physician Overview

How Diana Maas, MD fits within the Endocrinology, Diabetes & Metabolism Physician landscape nationally.

8,078
Endocrinology, Diabetes & Metabolism Physician Providers in US
54
States with Endocrinology, Diabetes & Metabolism Physician
2,739
Avg Claims per Provider

Diana Maas, MD's 336 claims are below the specialty average of 2,739.

Nationwide Endocrinology, Diabetes & Metabolism Physician peers with similar MIPS or enrollment year

Two federal-record peer sets for Maas, both outside Wisconsin so the neighborhoods are not geographic containment.

Similar MIPS final score

Nearest same-specialty clinicians by CMS MIPS final score (80.5 here).

Fatima Elamin 80.5 MD Asif Anwar Surani 80.5 TX Heidi Peynado De Pena 80.5 MT Felice Caldarella 80.5 NJ

Same NPPES enumeration year (2006)

Same-specialty clinicians who entered the NPI registry in the same calendar year, outside this state.

Robert Sjoberg Duluth, MN Philip Rasulo Bradenton, FL Edmund Giegerich Brooklyn, NY Susan Abend Sarasota, FL

Nearby Endocrinology, Diabetes & Metabolism Physician Providers in Wisconsin

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

One of 144 Endocrinology, Diabetes & Metabolism Physician providers enrolled in Wisconsin, 5 are shown here.

Dr. Laura Andrews
MD
Menasha, WI
Dr. Rishika Anil
MD
Milwaukee, WI
Dr. Arnold Asp
MD
La Crosse, WI
Dr. Pamela Baeten
M.D.
Green Bay, WI
Dr. Adrienne Barnosky
D.O.
Wauwatosa, WI

Compare Endocrinology, Diabetes & Metabolism Physician nationally: see state-by-state distribution →

Frequently Asked Questions

What is Diana Maas, MD's specialty? ▼
Diana Maas, MD specializes in Endocrinology, Diabetes & Metabolism Physician and practices in Milwaukee, Wisconsin. Credentials: MD.
How much does Diana Maas, MD prescribe under Medicare Part D? ▼
In 2024, Diana Maas, MD wrote 336 Medicare Part D claims totaling $23K in drug costs for 130 beneficiaries.
What is Diana Maas, MD's Medicare quality score? ▼
Diana Maas, MD has a CMS MIPS Final Score of 80.5/100 (Quality: 66.2, Cost: 68.6). The average MIPS Final Score across the 454,083 clinicians with at least one published category score is 83.5; clinicians whose score CMS assigned without scoring any category are excluded from that average. Source: CMS Merit-based Incentive Payment System (MIPS) 2023.
Where is Diana Maas, MD located? ▼
Diana Maas, MD is located at FROEDTERT & MED COLLEGE CLIN - EAST, Milwaukee, WI, 53226. Phone: (414) 805-3666.
What is Diana Maas, MD's NPI number? ▼
Diana Maas, MD's National Provider Identifier (NPI) is 1427009273, issued on 05/15/2006.
Does Diana Maas, MD prescribe more brand-name or generic drugs? ▼
Diana Maas, MD's prescribing is 46% brand-name and 50% generic drugs by claim count, with $12K in brand drug costs.
How many Endocrinology, Diabetes & Metabolism Physician providers are there in the US? ▼
There are 8,078 Endocrinology, Diabetes & Metabolism Physician providers across 54 states in the US. The average Endocrinology, Diabetes & Metabolism Physician provider writes 2,739 Medicare Part D claims per year.
What drugs does Diana Maas, MD prescribe most often? ▼
Based on 2024 Medicare Part D data, Diana Maas, MD's most frequently prescribed drugs include Levothyroxine Sodium, Hydrocortisone, Synthroid. This reflects Medicare Part D prescriptions only and does not include commercial insurance or other payer types.
Does Diana Maas, MD accept Medicare? ▼
Diana Maas, MD appears in CMS Medicare data with 336 Part D claims and 130 Medicare beneficiaries in 2024. Contact the provider's office directly to confirm current Medicare enrollment and accepted plans.
How can I verify Diana Maas, MD's credentials? ▼
Diana Maas, MD's NPI is 1427009273 with credentials MD. 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 (2024). Includes claims, drug costs, beneficiaries, and opioid prescribing rates.
Quality Performance
CMS Merit-based Incentive Payment System (MIPS) - 2023 performance year.
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 August 2026 (NPPES) / 2024 (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 editorial process.

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 August 2026.