2026 NPPES data Internal Medicine Physician NPI 1558362244 MD
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Gary Bubak, MD

Internal Medicine Physician in Wagner, South Dakota. This profile is drawn from the federal National Provider Identifier Registry (CMS NPPES), which lists more than 7 million U.S. healthcare providers — including 172,858 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
750
Medicare Part D claims · 128 beneficiaries · Internal Medicine Physician avg: 3K
Compiled from official public sources by the PlainDoctor editorial team.

What the federal data shows

Gary Bubak, MD filed 750 Medicare Part D claims in 2023 as a Internal Medicine Physician in Wagner, South Dakota.

750
Part D claims, 2023

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.

Gary Bubak, MD's Medicare Part D volume vs every U.S. prescriber

Total Medicare Part D claims, 2023 — across all CMS prescribers nationally

750 Top 29% higher than 71% of 1,370,886 prescribers

0–200: 670,926 prescribers (49%). Below this entry. 200–400: 182,923 prescribers (13%). Below this entry. 400–600: 90,619 prescribers (7%). Below this entry. 600–800: 56,224 prescribers (4%). This entry sits in this band. 800–1,000: 40,919 prescribers (3%). Above this entry. 1,000–1,200: 31,827 prescribers (2%). Above this entry. 1,200–1,400: 26,224 prescribers (2%). Above this entry. 1,400–1,600: 21,710 prescribers (2%). Above this entry. 1,600–1,800: 19,072 prescribers (1%). Above this entry. 1,800–2,000: 16,451 prescribers (1%). Above this entry. 2,000–2,200: 213,991 prescribers (16%). Above this entry. This provider 0 2K+ every Part D prescriber (claims/yr), bucketed by value

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)

Gary Bubak, 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 Gary Bubak, MD?

Quality data not reported

NPI registry status

Active

Issued 08/03/2005

NPI 1558362244

Primary specialty

Internal Medicine Physician

High-volume

172,858 US NPIs in this specialty

Medicare Part D claims

750 72% vs specialty avg

2023 prescription claims

Specialty avg: 2,716

Specialty distribution in South Dakota

How Internal Medicine Physician compares to other specialties among South Dakota providers

South Dakota providers

Largest specialties in South Dakota (% of in-state providers)

Physical Therapist — 5.6%Physical Therapist5.6%Pharmacist — 5.5%Pharmacist5.5%Registered Nurse — 4.8%Registered Nurse4.8%Family Nurse Practitioner — 4.7%Family Nurse Practitioner4.7%Mental Health Counselor — 4%Mental Health Counselor4%Physician Assistant — 3.7%Physician Assistant3.7%Internal Medicine Physician — 1.9%Internal Medicine Physician1.9%
Largest specialties in South Dakota (% of in-state providers)

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).

Gary Bubak, MD appears in the CMS NPPES registry as a Internal Medicine Physician provider holding MD credentials at 517 3RD ST SW, Wagner, SD, 57380, with a listed phone of (605) 384-5457. NPI 1558362244 was issued on 08/03/2005. Because NPPES data is self-reported by the provider and refreshed monthly, the address, phone, and specialty reflect what Bubak 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 750 prescription claims written by this provider, covering 128 Medicare beneficiaries and totaling roughly $52K in drug spend. 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

517 3RD ST SW
Wagner, SD 57380

Provider Details

NPI 1558362244
Specialty Internal Medicine Physician
Credentials MD
Gender Male
NPI Issued 08/03/2005

Medicare Part D Prescribing Data

CMS Medicare Part D prescriber-level data for calendar year 2023.

750
Total Claims
$52K
Total Drug Cost
128
Medicare Beneficiaries

Prescribing Breakdown

30-Day Fills
1,366
Total Day Supply
40,121
Generic Drug Cost
$10K

Patient Demographics

Average Patient Age
78.0 years
Avg HCC Risk Score
1.04
Gender Split
58% female / 42% male

Top Prescribed Drugs (Medicare Part D)

Top drugs by claim count for calendar year 2023. Based on Medicare Part D data only.

What Gary Bubak, MD prescribes most

Top Medicare Part D drugs by claim count, 2023

claims
Source CMS Medicare Part D Prescriber Public Use File As of 2023
Drug Claims
Amlodipine Besylate
62
Losartan Potassium
45
Atorvastatin Calcium
43
Rosuvastatin Calcium
38
Eliquis
Apixaban
36
Levothyroxine Sodium
34
Sertraline Hcl
30
Metoprolol Succinate
25
Lisinopril
24
Metformin Hcl
24

* 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 Gary Bubak, MD 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

Gary Bubak, MD's 750 claims are below the specialty average of 2,716.

Nearby Internal Medicine Physician Providers in South Dakota

Other clinicians with the same primary specialty enrolled in South Dakota, drawn from the same CMS NPPES roster as Bubak.

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 South Dakota 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.

Frequently Asked Questions

What is Gary Bubak, MD's specialty?
Gary Bubak, MD specializes in Internal Medicine Physician and practices in Wagner, South Dakota. Credentials: MD.
How much does Gary Bubak, MD prescribe under Medicare Part D?
In 2023, Gary Bubak, MD wrote 750 Medicare Part D claims totaling $52K in drug costs for 128 beneficiaries.
Where is Gary Bubak, MD located?
Gary Bubak, MD is located at 517 3RD ST SW, Wagner, SD, 57380. Phone: (605) 384-5457.
What is Gary Bubak, MD's NPI number?
Gary Bubak, MD's National Provider Identifier (NPI) is 1558362244, issued on 08/03/2005.
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 Gary Bubak, MD prescribe most often?
Based on 2023 Medicare Part D data, Gary Bubak, MD's most frequently prescribed drugs include Amlodipine Besylate, Losartan Potassium, Atorvastatin Calcium. This reflects Medicare Part D prescriptions only and does not include commercial insurance or other payer types.
Does Gary Bubak, MD accept Medicare?
Gary Bubak, MD appears in CMS Medicare data with 750 Part D claims and 128 Medicare beneficiaries in 2023. Contact the provider's office directly to confirm current Medicare enrollment and accepted plans.
How can I verify Gary Bubak, MD's credentials?
Gary Bubak, MD's NPI is 1558362244 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

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.