NPI registry status
Active
2026 NPPES data Internal Medicine Physician NPI 1487686614 MD
Verify on CMS → Mark Bostwick, MD
Internal Medicine Physician in Port Washington, 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 172,737 in 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
9K
Medicare Part D claims · 570 beneficiaries · Internal Medicine Physician avg: 3K
Generic prescribing
89%
generic claims · 10% brand-name · higher generic rates reduce patient out-of-pocket costs
Source: CMS Medicare Part D Prescriber Public Use File, 2023
What the federal data shows
Mark Bostwick, MD filed 9,038 Medicare Part D claims in 2023 as an Internal Medicine Physician in Port Washington, Wisconsin, prescribing 89% generic.
- 9K
- Part D claims, 2023
- 89%
- generic prescribing
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.
Mark Bostwick, MD's Medicare Part D volume vs every U.S. prescriber
Total Medicare Part D claims, 2023, across all CMS prescribers nationally
9,038 Top 2% higher than 98% 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)
Mark Bostwick, MD 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 Mark Bostwick, MD?
Quality data not reportedPrimary specialty
Internal Medicine Physician
Medicare Part D claims
9,038 233% vs specialty avg
Specialty distribution in Wisconsin
How Internal Medicine Physician compares to other specialties among Wisconsin 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 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).
Mark Bostwick, MD appears in the CMS NPPES registry as an Internal Medicine Physician provider holding MD credentials at 1777 W GRAND AVENUE, Port Washington, WI, 53074, with a listed phone of (262) 284-3456. NPI 1487686614 was issued on 07/07/2006.
Medicare Part D records for calendar year 2023 show 9,038 prescription claims written by this provider, covering 570 Medicare beneficiaries and totaling roughly $613K in drug spend, split 10% brand-name and 89% generic by claim count, with an opioid prescribing rate of 2.3%.
Internal Medicine Physician is a high-volume specialty nationwide, with 172,737 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
Provider Details
| NPI | 1487686614 |
|---|---|
| Specialty | Internal Medicine Physician |
| Credentials | MD |
| Gender | Male |
| NPI Issued | 07/07/2006 |
Brand vs generic prescribing mix · Typical
Mark Bostwick, MD - brand share 10.0%
Internal Medicine Physician average
10% brand-name claims vs 89% generic, on 9,038 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.
9,038
Total Claims
$613K
Total Drug Cost
570
Medicare Beneficiaries
Prescribing Breakdown
- 30-Day Fills
- 19,297
- Total Day Supply
- 556,574
- Brand vs Generic
- 10% brand / 89% generic
- Brand Drug Cost
- $469K
- Generic Drug Cost
- $142K
- Opioid Claims
- 206 (2.3% rate)
- Antibiotic Claims
- 242
Patient Demographics
- Average Patient Age
- 74.3 years
- Avg HCC Risk Score
- 1.27
- Gender Split
- 40% female / 60% male
- Age Distribution
- <65: 38, 65-74: 274, 75-84: 175, 85+: 83
Top Prescribed Drugs (Medicare Part D)
Top drugs by claim count for calendar year 2023. Based on Medicare Part D data only.
What Mark Bostwick, MD prescribes most
Top Medicare Part D drugs by claim count, 2023
- Atorvastatin Calcium
Atorvastatin Calcium
656 claims
- Losartan Potassium
Losartan Potassium
397 claims
- Amlodipine Besylate
Amlodipine Besylate
294 claims
- Lisinopril
Lisinopril
289 claims
- Levothyroxine Sodium
Levothyroxine Sodium
267 claims
- Hydrochlorothiazide 229
Hydrochlorothiazide
229 claims
- Atenolol 213
Atenolol
213 claims
- Metoprolol Succinate 209
Metoprolol Succinate
209 claims
| Drug | Claims |
|---|---|
| Atorvastatin Calcium | 656 |
| Losartan Potassium | 397 |
| Amlodipine Besylate | 294 |
| Lisinopril | 289 |
| Levothyroxine Sodium | 267 |
| Hydrochlorothiazide | 229 |
| Atenolol | 213 |
| Metoprolol Succinate | 209 |
| Omeprazole | 204 |
| Simvastatin | 198 |
* 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 Mark Bostwick, MD fits within the Internal Medicine Physician landscape nationally.
172,737
Internal Medicine Physician Providers in US
56
States with Internal Medicine Physician
2,716
Avg Claims per Provider
Mark Bostwick, MD's 9,038 claims are above the specialty average of 2,716.
Nearby Internal Medicine Physician Providers in Wisconsin
Other clinicians with the same primary specialty enrolled in Wisconsin, drawn from the same CMS NPPES roster as Bostwick.
Dr. Sheetal Aatrai
MD
Marshfield, WI
Dr. Ihab Abdalrahman
MD
Marshfield, WI
Dr. Khalid Abdelgadir
MD
Manitowoc, WI
Dr. Kareem Abdelhadi
MD
Rice Lake, WI
Dr. Mesfin Abdissa
MD
Milwaukee, WI
Compare Internal Medicine 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 Wisconsin medical board, federal registration is not a license check. Credential verification guide
- Weigh a second option: compare this provider with a nearby 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.
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Frequently Asked Questions
What is Mark Bostwick, MD's specialty? ▼
Mark Bostwick, MD specializes in Internal Medicine Physician and practices in Port Washington, Wisconsin. Credentials: MD.
How much does Mark Bostwick, MD prescribe under Medicare Part D? ▼
In 2023, Mark Bostwick, MD wrote 9,038 Medicare Part D claims totaling $613K in drug costs for 570 beneficiaries.
Where is Mark Bostwick, MD located? ▼
Mark Bostwick, MD is located at 1777 W GRAND AVENUE, Port Washington, WI, 53074. Phone: (262) 284-3456.
What is Mark Bostwick, MD's NPI number? ▼
Mark Bostwick, MD's National Provider Identifier (NPI) is 1487686614, issued on 07/07/2006.
Does Mark Bostwick, MD prescribe more brand-name or generic drugs? ▼
Mark Bostwick, MD's prescribing is 10% brand-name and 89% generic drugs by claim count, with $469K in brand drug costs.
Does Mark Bostwick, MD prescribe opioids? ▼
Yes, Mark Bostwick, MD had 206 opioid claims in 2023 with an opioid prescribing rate of 2.3%.
How many Internal Medicine Physician providers are there in the US? ▼
There are 172,737 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 Mark Bostwick, MD prescribe most often? ▼
Based on 2023 Medicare Part D data, Mark Bostwick, MD's most frequently prescribed drugs include Atorvastatin Calcium, Losartan Potassium, Amlodipine Besylate. This reflects Medicare Part D prescriptions only and does not include commercial insurance or other payer types.
Does Mark Bostwick, MD accept Medicare? ▼
Mark Bostwick, MD appears in CMS Medicare data with 9,038 Part D claims and 570 Medicare beneficiaries in 2023. Contact the provider's office directly to confirm current Medicare enrollment and accepted plans.
How can I verify Mark Bostwick, MD's credentials? ▼
Mark Bostwick, MD's NPI is 1487686614 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 (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
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.