NPI registry status
Active
2026 NPPES data Internal Medicine Physician NPI 1548228810 M.D.
Verify on CMS → Gregory Mumm, M.D.
Internal Medicine Physician in Sioux Falls, 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 172,737 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
4K
Medicare Part D claims · 498 beneficiaries · Internal Medicine Physician avg: 3K
Generic prescribing
82%
generic claims · 17% brand-name · higher generic rates reduce patient out-of-pocket costs
Industry payments
$133.02
6 payments · CMS Open Payments (Sunshine Act)
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
Gregory Mumm, M.D. filed 3,590 Medicare Part D claims in 2023 as a Internal Medicine Physician in Sioux Falls, South Dakota, prescribing 82% generic.
- 4K
- Part D claims, 2023
- 82%
- 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.
Gregory Mumm, M.D.'s Medicare Part D volume vs every U.S. prescriber
Total Medicare Part D claims, 2023, across all CMS prescribers nationally
3,590 Top 10% higher than 90% 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)
Gregory Mumm, M.D. practices in an ABMS-board-eligible specialty and shows active CMS Medicare participation + 1 hospital affiliation - 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 Gregory Mumm, M.D.?
Quality data not reportedPrimary specialty
Internal Medicine Physician
Medicare Part D claims
3,590 32% vs specialty avg
Specialty distribution in South Dakota
How Internal Medicine Physician compares to other specialties among South Dakota 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).
Gregory Mumm, M.D. appears in the CMS NPPES registry as an Internal Medicine Physician provider holding M.D. credentials at 6100 S LOUISE AVE STE 1130, Sioux Falls, SD, 57108, with a listed phone of (605) 504-1600. NPI 1548228810 was issued on 05/03/2006.
Medicare Part D records for calendar year 2023 show 3,590 prescription claims written by this provider, covering 498 Medicare beneficiaries and totaling roughly $2.4 million in drug spend, split 17% brand-name and 82% generic by claim count, with an opioid prescribing rate of 1.9%.
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 | 1548228810 |
|---|---|
| Specialty | Internal Medicine Physician |
| Credentials | M.D. |
| Gender | Male |
| NPI Issued | 05/03/2006 |
Hospital and facility affiliations
Facilities where Gregory Mumm, M.D. 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.
Avera Mckennan
Sioux Falls, SD
Affiliations sourced from CMS Doctors and Clinicians National Downloadable File; hospital ratings from CMS Hospital General Information dataset (cross-referenced by facility name + state).
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 Gregory Mumm, M.D.. Source: openpaymentsdata.cms.gov.
Total received
$133
Largest payer
Sandoz Inc.
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.
Brand vs generic prescribing mix · Typical
Gregory Mumm, M.D. - brand share 17.0%
Internal Medicine Physician average
17% brand-name claims vs 82% generic, on 3,590 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.
3,590
Total Claims
$2.4M
Total Drug Cost
498
Medicare Beneficiaries
Prescribing Breakdown
- 30-Day Fills
- 6,719
- Total Day Supply
- 196,953
- Brand vs Generic
- 17% brand / 82% generic
- Brand Drug Cost
- $2.3M
- Generic Drug Cost
- $125K
- Opioid Claims
- 69 (1.9% rate)
- Antibiotic Claims
- 18
Patient Demographics
- Average Patient Age
- 72.3 years
- Avg HCC Risk Score
- 1.48
- Gender Split
- 64% female / 36% male
- Age Distribution
- <65: 52, 65-74: 249, 75-84: 172, 85+: 25
Top Prescribed Drugs (Medicare Part D)
Top drugs by claim count for calendar year 2023. Based on Medicare Part D data only.
What Gregory Mumm, M.D. prescribes most
Top Medicare Part D drugs by claim count, 2023
- Methotrexate
Methotrexate
863 claims
- Hydroxychloroquine…
Hydroxychloroquine Sulfate
482 claims
- Prednisone 278
Prednisone
278 claims
- Leflunomide 270
Leflunomide
270 claims
- Allopurinol 155
Allopurinol
155 claims
- Sulfasalazine 122
Sulfasalazine
122 claims
- Enbrel Sureclick 101
Enbrel Sureclick
101 claims
- Alendronate Sodium 99
Alendronate Sodium
99 claims
| Drug | Claims |
|---|---|
| Methotrexate Methotrexate Sodium | 863 |
| Hydroxychloroquine Sulfate | 482 |
| Prednisone | 278 |
| Leflunomide | 270 |
| Allopurinol | 155 |
| Sulfasalazine | 122 |
| Enbrel Sureclick Etanercept | 101 |
| Alendronate Sodium | 99 |
| Duloxetine Hcl | 93 |
| Gabapentin | 90 |
* 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 Gregory Mumm, M.D. 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
Gregory Mumm, M.D.'s 3,590 claims are above 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 Mumm.
Dr. Mouhanna Abu Ghanimeh
M.D.
Sioux Falls, SD
Dr. Emad Abu Sitta
M.D
Sioux Falls, SD
Dr. Joyce Achenjang
M.D
Pine Ridge, SD
Dr. Comfort Agaba
MD
Sioux Falls, SD
Dr. Abdalah Ahmed
MD
Sioux Falls, SD
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.
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Frequently Asked Questions
What is Gregory Mumm, M.D.'s specialty? ▼
Gregory Mumm, M.D. specializes in Internal Medicine Physician and practices in Sioux Falls, South Dakota. Credentials: M.D..
How much does Gregory Mumm, M.D. prescribe under Medicare Part D? ▼
In 2023, Gregory Mumm, M.D. wrote 3,590 Medicare Part D claims totaling $2.4M in drug costs for 498 beneficiaries.
Where is Gregory Mumm, M.D. located? ▼
Gregory Mumm, M.D. is located at 6100 S LOUISE AVE STE 1130, Sioux Falls, SD, 57108. Phone: (605) 504-1600.
What is Gregory Mumm, M.D.'s NPI number? ▼
Gregory Mumm, M.D.'s National Provider Identifier (NPI) is 1548228810, issued on 05/03/2006.
Does Gregory Mumm, M.D. prescribe more brand-name or generic drugs? ▼
Gregory Mumm, M.D.'s prescribing is 17% brand-name and 82% generic drugs by claim count, with $2.3M in brand drug costs.
Does Gregory Mumm, M.D. prescribe opioids? ▼
Yes, Gregory Mumm, M.D. had 69 opioid claims in 2023 with an opioid prescribing rate of 1.9%.
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 Gregory Mumm, M.D. prescribe most often? ▼
Based on 2023 Medicare Part D data, Gregory Mumm, M.D.'s most frequently prescribed drugs include Methotrexate, Hydroxychloroquine Sulfate, Prednisone. This reflects Medicare Part D prescriptions only and does not include commercial insurance or other payer types.
Does Gregory Mumm, M.D. accept Medicare? ▼
Gregory Mumm, M.D. appears in CMS Medicare data with 3,590 Part D claims and 498 Medicare beneficiaries in 2023. Contact the provider's office directly to confirm current Medicare enrollment and accepted plans.
How can I verify Gregory Mumm, M.D.'s credentials? ▼
Gregory Mumm, M.D.'s NPI is 1548228810 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.