NPI registry status
Active
2026 NPPES data Nephrology Physician NPI 1134118326 M.D.,
Verify on CMS → William Johnson, M.D.,
Nephrology Physician in Frederick, Maryland.
This profile is drawn from the federal National Provider Identifier Registry (CMS NPPES), which lists more than 7 million U.S. healthcare providers - including 10,569 in Nephrology 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
93
Medicare Part D claims · 51 beneficiaries · Nephrology Physician avg: 1K
Industry payments
$19.57
1 payments · CMS Open Payments (Sunshine Act)
Compiled from official public sources by the PlainDoctor editorial team.
What the federal data shows
William Johnson, M.D., filed 93 Medicare Part D claims in 2023 as a Nephrology Physician in Frederick, Maryland.
- 93
- Part D claims, 2023
- $19.57
- industry payments (Sunshine Act)
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.
William Johnson, M.D.,'s Medicare Part D volume vs every U.S. prescriber
Total Medicare Part D claims, 2023, across all CMS prescribers nationally
93 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-eligible specialty (heuristic, not verified)
William Johnson, 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 William Johnson, M.D.,?
Quality data not reportedPrimary specialty
Nephrology Physician
Medicare Part D claims
93 94% vs specialty avg
Specialty distribution in Maryland
How Nephrology Physician compares to other specialties among Maryland 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 Nephrology 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).
William Johnson, M.D., appears in the CMS NPPES registry as a Nephrology Physician provider holding M.D., credentials at 140 THOMAS JOHNSON DR, Frederick, MD, 21702, with a listed phone of (301) 694-7788. NPI 1134118326 was issued on 10/19/2005.
Medicare Part D records for calendar year 2023 show 93 prescription claims written by this provider, covering 51 Medicare beneficiaries and totaling roughly $7K in drug spend.
Nephrology Physician is a mid-sized specialty nationwide, with 10,569 enrolled providers across 55 states and an average of 1,454 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 | 1134118326 |
|---|---|
| Specialty | Nephrology Physician |
| Credentials | M.D., |
| Gender | Male |
| NPI Issued | 10/19/2005 |
Industry payments received (2024) - CMS Open Payments transparency data
The federal Physician Payments Sunshine Act (part of the Affordable Care Act) requires drug and medical-device manufacturers + group purchasing organizations to publicly report payments and other transfers of value to physicians and teaching hospitals. The data below covers 2024 for William Johnson, M.D.,. Source: openpaymentsdata.cms.gov.
Total received
$20
Largest payer
AstraZeneca Pharmaceuticals LP
Most common payment type
Food and Beverage
Industry payments are not necessarily indicators of bias, they include research funding, consulting fees for evidence-based work, royalties for inventions, food at conferences, and similar items. The disclosure exists for transparency. Read our methodology for how we interpret this data.
Medicare Part D Prescribing Data
CMS Medicare Part D prescriber-level data for calendar year 2023.
93
Total Claims
$7K
Total Drug Cost
51
Medicare Beneficiaries
Prescribing Breakdown
- 30-Day Fills
- 238
- Total Day Supply
- 7,099
- Generic Drug Cost
- $6K
Patient Demographics
- Average Patient Age
- 73.0 years
- Avg HCC Risk Score
- 3.16
- Gender Split
- 41% female / 59% male
Top Prescribed Drugs (Medicare Part D)
Top drugs by claim count for calendar year 2023. Based on Medicare Part D data only.
| Drug | Claims |
|---|---|
| Calcitriol | 14 |
* Counts below 11 are suppressed by CMS for patient privacy. Generic names shown where available from CMS Part D data.
Nephrology Physician Overview
How William Johnson, M.D., fits within the Nephrology Physician landscape nationally.
10,569
Nephrology Physician Providers in US
55
States with Nephrology Physician
1,454
Avg Claims per Provider
William Johnson, M.D.,'s 93 claims are below the specialty average of 1,454.
Nearby Nephrology Physician Providers in Maryland
Other clinicians with the same primary specialty enrolled in Maryland, drawn from the same CMS NPPES roster as Johnson.
Dr. Hossam Abdalla
M.D.
Glen Burnie, MD
Dr. Marwa Abdalla
MBBS
Waldorf, MD
Dr. Veena Acharya
MD
Bel Air, MD
Dr. Rohini Adhikarla
M.D
Lutherville Timonium, MD
Dr. Muzna Adil
M.D.
Suitland, MD
Compare Nephrology Physician nationally: see state-by-state distribution →
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 Maryland medical board, federal registration is not a license check. Credential verification guide
- Weigh a second option: compare this provider with a nearby Nephrology 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
Learn more about finding, verifying, and understanding healthcare providers.
How to Find a Doctor
Step-by-step guide to choosing a provider
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Check NPI, board certification & license status
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
Telehealth Guide
Virtual care options and coverage in 2026
Explore Maryland
Frequently Asked Questions
What is William Johnson, M.D.,'s specialty? ▼
William Johnson, M.D., specializes in Nephrology Physician and practices in Frederick, Maryland. Credentials: M.D.,.
How much does William Johnson, M.D., prescribe under Medicare Part D? ▼
In 2023, William Johnson, M.D., wrote 93 Medicare Part D claims totaling $7K in drug costs for 51 beneficiaries.
Where is William Johnson, M.D., located? ▼
William Johnson, M.D., is located at 140 THOMAS JOHNSON DR, Frederick, MD, 21702. Phone: (301) 694-7788.
What is William Johnson, M.D.,'s NPI number? ▼
William Johnson, M.D.,'s National Provider Identifier (NPI) is 1134118326, issued on 10/19/2005.
How many Nephrology Physician providers are there in the US? ▼
There are 10,569 Nephrology Physician providers across 55 states in the US. The average Nephrology Physician provider writes 1,454 Medicare Part D claims per year.
What drugs does William Johnson, M.D., prescribe most often? ▼
Based on 2023 Medicare Part D data, William Johnson, M.D.,'s most frequently prescribed drugs include Calcitriol. This reflects Medicare Part D prescriptions only and does not include commercial insurance or other payer types.
Does William Johnson, M.D., accept Medicare? ▼
William Johnson, M.D., appears in CMS Medicare data with 93 Part D claims and 51 Medicare beneficiaries in 2023. Contact the provider's office directly to confirm current Medicare enrollment and accepted plans.
How can I verify William Johnson, M.D.,'s credentials? ▼
William Johnson, M.D.,'s NPI is 1134118326 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
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.