Quick answers
- Does John F. Brennan accept Medicare assignment?
- Yes. Medicare's clinician data says John F. Brennan accepts Medicare assignment (the Medicare-approved amount as full payment for covered services), as of October 2, 2026. Ask the office to confirm before your visit.
- How many Medicare patients does John F. Brennan see?
- In 2024, CMS data shows 260 Original Medicare patients and 777 services for John F. Brennan. This counts Original Medicare only and measures volume, not quality.
- What is John F. Brennan's NPI number?
- 1154351153. The NPI (National Provider Identifier) is the clinician's permanent federal ID; you can look it up in the official NPI Registry.
Medicare activity in 2024
Official CMS public-use data for John F. Brennan, data year 2024 (released May 21, 2026). It covers Original Medicare (fee-for-service) patients only, not Medicare Advantage or other insurance. It shows volume, not quality or outcomes. CMS hides any count of 10 or fewer patients.
| Original Medicare patients | 260 |
|---|---|
| Services billed to Medicare | 777 |
| Different services or procedures | 19 |
| Participating Medicare provider | Yes |
| Average age of these patients | 72 |
Most frequent services
- Established patient office or other outpatient visit with low level od decision making, if using time, 20 minutes or more (99213)260 services
- Dialysis services, 4 or more physician visits per month (20 years or older) (90960)137 services
- Subsequent hospital care with straightforward or low level of medical decision making, per day, if using time, at least 25 minutes (99231)92 services
- Dialysis services, 2-3 physician visits per month (20 years or older) (90961)59 services
- Home dialysis services per month (20 years or older) (90966)51 services
Chronic conditions among these patients
Share of this clinician’s Original Medicare patients with each condition, as published by CMS (it describes the patients, not the care given).
- High blood pressure75%
- High cholesterol75%
- Chronic kidney disease75%
- Diabetes56%
- Arthritis50%
- Ischemic heart disease37%
Hospitals where John F. Brennan works
Medicare's Facility Affiliation Data lists John F. Brennan at these hospitals (updated October 2, 2026). Each hospital page shows its address, phone, emergency services, Medicare rating and all its clinicians. Star rating and emergency services: Hospital General Information (CMS), data updated October 26, 2026.
- Ascension All Saints HospitalRacine, WI · Acute Care Hospital · Medicare rating: 2 of 5 stars · Emergency services: listed by Medicare · CCN 520096
- Ascension SE Wisconsin HospitalMilwaukee, WI · Acute Care Hospital · Medicare rating: 5 of 5 stars · Emergency services: listed by Medicare · CCN 520136
- Aurora Medical Center KenoshaKenosha, WI · Acute Care Hospital · Medicare rating: 4 of 5 stars · Emergency services: listed by Medicare · CCN 520189
Practice locations
Addresses where John F. Brennan is enrolled with Medicare (CMS data updated October 2, 2026).
- 2901 W Kinnickinnic River PkwyMilwaukee, WI 53215 (414) 259‑8917
- 3803 Spring St, Suite 600Mount Pleasant, WI 53405 (262) 687‑8312
Group practices
Medicare enrollment lists John F. Brennan as a member of these groups (CMS data updated October 2, 2026).
- Ascension Medical Group-Southeast Wisconsin Inc545 clinicians in the group
- Milwaukee Nephrologists SC21 clinicians in the group
Specialties
- Nephrologyprimary
- Internal Medicinealso
Other nephrologists in Milwaukee
Clinicians with the same Medicare primary specialty in Milwaukee, WI — not a recommendation.
Other clinicians in Ascension Medical Group-Southeast Wisconsin Inc
Medicare enrollment lists these clinicians in the same group practice — not a recommendation.
Clinician information
| Credential | MD |
|---|---|
| Medical school | R Franklin University Of Med & Sci/chicago Medical School |
| Graduation year | 1991 (35 years since medical school) |
| Gender (as listed) | Male |
| Medicare assignment | Accepts (Medicare-approved amount as full payment) |
| NPI (National Provider Identifier) | 1154351153 |
| Corrections | Report an error or suggest an update → |
Most corrections must be made at the source: clinicians update their NPI Registry record (NPPES) and their Medicare enrollment (PECOS); this page follows the next data release.
Sources
- Facility Affiliation Data — Centers for Medicare & Medicaid Services (CMS), data updated October 2, 2026, retrieved October 29, 2026
- Hospital General Information — CMS, data updated October 26, 2026, retrieved November 13, 2026
- National Downloadable File (Doctors and Clinicians) — CMS, data updated October 2, 2026, retrieved October 29, 2026
- Medicare Physician & Other Practitioners - by Provider — CMS, data year 2024, released May 21, 2026; Medicare Physician & Other Practitioners - by Provider and Service
- NPI Registry — U.S. Department of Health and Human Services (NPPES), the clinician’s official record
- Medicare Care Compare — official Medicare tool to look up clinicians