Michael Merle Maddy
Internal Medicine - Nephrology โข Duluth, MN
400 E 3rd St
Duluth, MN 558051951
This profile restates public CMS/NPPES data; T-MedInfo gives no medical advice — consult a licensed professional, and call 911 for emergencies.
-
Michael Maddy is listed in NPPES under Internal Medicine - Nephrology.
-
NPI assigned on June 26, 2006; this date does not establish years in practice.
-
Published CMS data list 72 Original Medicare Part B services in 2021.
Source: CMS, Medicare Physician & Other Practitioners โ by Provider and Service, 2021. Published rows only; this is not a quality measure.
-
Published Part B service records, 2021:
- 90961 โ Dialysis services, 2-3 physician visits per month (20 years or older): 59 service units.
- 99213 โ Established patient outpatient office visit: 13 service units.
Source: CMS, Medicare Physician & Other Practitioners โ by Provider and Service, 2021. Units differ by code; these are not visits or a measure of quality.
CPTยฎ only copyright 2020 American Medical Association. All rights reserved. Service names are shortened from CPT Consumer Friendly Descriptors (CMS data, 2021). CPT notice
See the full table ยท Guide: How to read Medicare Part B data
-
Published CMS data list 226 Medicare Part D prescriptions, including refills, in 2021.
Source: CMS, Medicare Part D Prescribers โ by Provider and Drug, 2021. Published rows only; this is not a quality measure.
-
Published Part D records, 2021:
- Losartan Potassium โ 40 prescription fills, including refills.
- Torsemide โ 34 prescription fills, including refills.
- Amlodipine Besylate โ 30 prescription fills, including refills.
Source: CMS, Medicare Part D Prescribers โ by Provider and Drug, 2021. Drug names come from pharmacy claims. Listing a drug here is not an endorsement or a recommendation.
See all 10 records in the table ยท Guide: How to read Medicare Part D prescriber data
-
Medicare Part B services went from 164 in 2017 to 72 in 2021.
Source: CMS, Medicare Physician & Other Practitioners โ by Provider and Service, 2017โ2021.
Practice Location & Contact Primary Location
400 E 3rd St
Duluth, MN 558051951
Matched by practice address or phone in NPPES. A shared address or phone does not confirm that this clinician works there.
What Public CMS Data Show
Internal Medicine - Nephrology: NPPES taxonomy is a reported classification, not proof of board certification.
Medicare patients
41 people with Original Medicare in 2021
It gives a sense of how many people with Medicare this clinician treated that year.
Source: CMS, Medicare Physician & Other Practitioners โ by Provider, 2021.
Medicare-allowed amount
About $18,420 in 2021
The total amount Medicare approved for these services in 2021. It includes what Medicare paid and what patients or their other insurance owed, such as the deductible and coinsurance.
It shows the total cost of this clinician's Original Medicare services under Medicare's fee rules.
What this does not show: Medicare-allowed amount
This is not the clinician's income. Part of it can go to a clinic or group practice, staff, equipment or drugs. It is not the price you will pay.
Source: CMS, Medicare Physician & Other Practitioners โ by Provider and Service, 2021.
Paid by Medicare
About $14,531 in 2021
The part of the Medicare-allowed amount that Medicare itself paid in 2021, after patients' deductibles and coinsurance.
The gap between the allowed amount and this number is roughly what patients and their other insurance paid.
What this does not show: Paid by Medicare
This is not the clinician's income and not a measure of quality.
Source: CMS, Medicare Physician & Other Practitioners โ by Provider and Service, 2021.
30-day fills
400 standardized 30-day fills in 2021
CMS converts prescriptions to 30-day supplies so they can be compared. A 90-day prescription counts as about three 30-day fills.
What this does not show: 30-day fills
It is not a count of patients and not a measure of quality.
Part D drug cost
$73,593 in 2021
The total cost of these prescriptions in 2021, paid by Medicare drug plans, patients and other payers together.
It shows the total spending on drugs this clinician prescribed, not what any one patient paid.
What this does not show: Part D drug cost
A higher cost often reflects the type of medicines a specialty uses. It is not your out-of-pocket cost and not a measure of quality.
Source: CMS, Medicare Part D Prescribers โ by Provider and Drug, 2021.
Industry payments (Open Payments)
No Open Payments records are listed for this clinician for 2019โ2025.
NPI first issued
2006
The year this clinician's National Provider Identifier (NPI) was issued. An NPI is a unique 10-digit ID that US health care providers use for billing.
What this does not show: NPI first issued
NPIs have been issued only since 2005, so this year is not necessarily when the clinician started practicing.
Source: CMS NPPES NPI Registry.
Medicare assignment not listed
CMS data do not show whether this clinician accepts Medicare assignment. This does not mean they do not accept Medicare. Ask the office.
Medicare assignment applies to Original Medicare. It does not tell you whether the clinician is in a Medicare Advantage plan's network, accepts other insurance, or is taking new patients.
Source: CMS Doctors and Clinicians, CMS release of October 2, 2026; Medicare.gov, โDoes your provider accept Medicare as full payment?โ
No telehealth indicator
CMS shows this indicator only when recent Medicare claims include telehealth services. The clinician may still offer telehealth; ask the office.
Source: CMS, Telehealth Indicator on Medicare Care Compare (fact sheet, January 2023); CMS Doctors and Clinicians, CMS release of October 2, 2026.
Compared with the same specialty in Duluth and Minnesota
Billing and prescribing volume is not a quality rating.
Medicare Part B
Comparisons use 2024 data. The latest CMS data for Michael Maddy are from 2021.
Medicare Part D
Comparisons use 2024 data. The latest CMS data for Michael Maddy are from 2021.
12 active clinicians are listed under Internal Medicine - Nephrology with a practice address in Duluth, MN (261 in Minnesota).
Addresses are self-reported to NPPES and may be out of date.
Telehealth indicator in Duluth
41.7% of these 12 clinicians have the CMS telehealth indicator.
83.3% of these 12 clinicians are listed by CMS as accepting Medicare assignment.
CMS data by year
Changes may reflect reporting, coverage or privacy limits, not changes in care quality.
-
Medicare Part B services
Medicare Part B services decreased 56% from 164 in 2017 to 72 in 2021.
- 2017: 164
- 2018: 233
- 2019: 681
- 2020: 338
- 2021: 72
-
Medicare-allowed amount
Medicare-allowed amount increased 81% from $10,175 in 2017 to $18,420 in 2021.
- 2017: $10,175
- 2018: $11,095
- 2019: $64,596
- 2020: $40,285
- 2021: $18,420
-
Paid by Medicare
Paid by Medicare increased 107% from $7,004 in 2017 to $14,531 in 2021.
- 2017: $7,004
- 2018: $7,393
- 2019: $50,468
- 2020: $31,081
- 2021: $14,531
-
Medicare Part D prescriptions
Medicare Part D prescriptions decreased 51% from 459 in 2017 to 226 in 2021.
- 2017: 459
- 2018: 271
- 2019: 214
- 2020: 231
- 2021: 226
-
30-day fills
30-day fills decreased 47% from 752 in 2017 to 400 in 2021.
- 2017: 752
- 2018: 534
- 2019: 368
- 2020: 410
- 2021: 400
-
Part D drug cost
Part D drug cost increased 1329% from $5,151 in 2017 to $73,593 in 2021.
- 2017: $5,151
- 2018: $12,175
- 2019: $2,660
- 2020: $30,268
- 2021: $73,593
Sources: CMS Medicare Physician & Other Practitioners (2021), CMS Medicare Part D Prescribers (2021), CMS Doctors and Clinicians, CMS release of October 2, 2026, CMS NPPES NPI Registry. Specialty names follow the NUCC Health Care Provider Taxonomy.
Text: T-MedInfo ยท Report an error.
Performed Procedures & Service Volume
CPTยฎ is a registered trademark of the American Medical Association. CPT codes, descriptions and other data only are copyright 2016โ2020 American Medical Association. All rights reserved. Applicable FARS/HHSARS apply. Descriptions of CPT codes are the AMA's CPT Consumer Friendly Descriptors as published by CMS in the Medicare Physician & Other Practitioners โ by Provider and Service data, 2017โ2021; they are plain-language summaries, not for clinical coding or documentation. HCPCS Level II codes and descriptions are from CMS. Fee schedules, relative value units, conversion factors and/or related components are not assigned by the AMA, are not part of CPT, and the AMA is not recommending their use. The AMA does not directly or indirectly practice medicine or dispense medical services. The AMA assumes no liability for data contained or not contained herein.
| HCPCS Code | Services | Patients | Submitted Charge | Medicare Allowed |
|---|---|---|---|---|
|
90961
Dialysis services, 2-3 physician visits per month (20 years or older)
|
59 | 13 | $1004.00 | $293.88 |
|
99213
Established patient office or other outpatient visit with low level od decision making, if using time, 20 minutes or more
|
13 | 12 | $220.00 | $83.16 |
Source: CMS Part B by Provider and Service, 2021; services under 11 beneficiaries omitted by CMS. Privacy limits
Submitted charges are billed amounts, not a price quote for your visit.
Medicare Part D Prescribing Profile & Medications
Medicare Part D prescriptions filled, including refills, in 2021.
| Brand Name | Generic Name | Prescriptions | Day Supply | Total Cost | Patients |
|---|---|---|---|---|---|
| Losartan Potassium | Losartan Potassium | 40 | 1,881 | $356.16 | 11 |
| Torsemide | Torsemide | 34 | 2,083 | $561.85 | โ |
| Amlodipine Besylate | Amlodipine Besylate | 30 | 1,448 | $196.10 | โ |
| Sevelamer Carbonate | Sevelamer Carbonate | 26 | 969 | $5,785.48 | โ |
| Furosemide | Furosemide | 22 | 1,026 | $185.85 | โ |
| Renvela | Sevelamer Carbonate | 18 | 540 | $34,689.42 | โ |
| Lisinopril | Lisinopril | 16 | 1,326 | $145.46 | โ |
| Metoprolol Succinate | Metoprolol Succinate | 14 | 1,140 | $922.85 | โ |
| Calcium Acetate | Calcium Acetate | 14 | 720 | $2,357.71 | โ |
| Velphoro | Sucroferric Oxyhydroxide | 12 | 360 | $28,391.66 | โ |
Source: CMS Part D by Provider and Drug, 2021; rows below 11 claims omitted by CMS; volume isn’t quality. Privacy limits
Specialties & License Numbers Reported to NPPES
NUCC Taxonomy Code: 207RN0300X
An internist who treats disorders of the kidney, high blood pressure, fluid and mineral balance and dialysis of body wastes when the kidneys do not function. This specialist consults with surgeons about kidney transplantation.
Additional State Medicaid & Healthcare Payer Identifiers
Clinicians Sharing This Practice Address or Phone
Clinicians sharing this NPPES address, phone or fax; a shared contact does not mean they work together.
Physician Assistant
Physician Assistant
Psychiatry & Neurology - Neurology
Doctor of Osteopathic Medicine (D.O.)
Nurse Practitioner - Family
Advanced Practice Registered Nurse, Certified Nurse Practitioner
Physician Assistant
Physician Assistant (Certified)
Family Medicine
Doctor of Medicine (M.D.)
Career & Practice History
NPI enumerated June 26, 2006.
No changes to the name, practice address, taxonomy or NPI status in this record have been observed in the monthly NPPES data files from January 2017 to November 2026.
NPI Administrative Meta
Other Internal Medicine - Nephrology Specialists in Duluth
- Dr. Hannah Kruger, MD
- Dr. Heather Muster, MD
- Dr. Danijela Mataic, MD
- Dr. Hassan Salameh, MD
- Dr. Sreedhar Devathi, MD
- Dr. Apurv Khanna, MD
Mailing Address
400 E 3rd St
Duluth, MN 558051951
Phone: 2187868364