Quick answers
- Which hospitals does John A. Key work at?
- Medicare's official clinician data lists John A. Key at 5 hospitals: Corewell Health Big Rapids Hospital, Corewell Health Pennock Hospital, Corewell Health Reed City Hospital, Spectrum Health and Spectrum Health United Hospital. This is where the clinician works or has privileges; call the hospital to confirm.
- Where does John A. Key see patients?
- Medicare's clinician data lists 23 practice locations, including Grand Rapids, MI, Hastings, MI and Muskegon, MI. Call before your visit to confirm the address.
- What is John A. Key's specialty?
- Medicare lists Cardiovascular Disease (Cardiology) as the primary specialty, and also Internal Medicine.
- Does John A. Key accept Medicare assignment?
- Yes. Medicare's clinician data says John A. Key accepts Medicare assignment (the Medicare-approved amount as full payment for covered services), as of 2026-10-02. Ask the office to confirm before your visit.
- What is the phone number for John A. Key?
- (616) 267-0115, as listed in official Medicare / NPI Registry data.
- What is John A. Key's NPI number?
- 1134103732. The NPI (National Provider Identifier) is the clinician's permanent federal ID; you can look it up in the official NPI Registry.
Hospitals where John A. Key works
Medicare's Facility Affiliation Data lists John A. Key at these hospitals (updated 2026-10-02). Each hospital page shows its address, phone, emergency services, Medicare rating and all its clinicians.
- Corewell Health Big Rapids HospitalBig Rapids, MI · Acute Care Hospital · CCN 230093
- Corewell Health Pennock HospitalHastings, MI · Critical Access Hospital · CCN 231339
- Corewell Health Reed City HospitalReed City, MI · Critical Access Hospital · CCN 231323
- Spectrum HealthGrand Rapids, MI · Acute Care Hospital · CCN 230038
- Spectrum Health United HospitalGreenville, MI · Acute Care Hospital · CCN 230035
Practice locations
Addresses where John A. Key is enrolled with Medicare (CMS data updated 2026-10-02). The first 5 of 23; the Medicare profile lists all.
- 100 Michigan Ave NEGrand Rapids, MI 49503
- 100 Michigan St NE Rm, 280 Corewell Health Medical Group WestGrand Rapids, MI 49503 (616) 267‑0115
- 1009 W Green St, Corewell Health Medical Group WestHastings, MI 49058 (269) 945‑1212
- 1840 Wealthy St SE, Corewell Health Medical Group WestGrand Rapids, MI 49506 (616) 885‑5000
- 1845 Holton RdMuskegon, MI 49445 (616) 885‑5000
Group practices
Medicare enrollment lists John A. Key as a member of this group (CMS data updated 2026-10-02).
- Spectrum Health Primary Care Partners2,294 clinicians in the group
Specialties
Find other Cardiovascular Disease (Cardiology) doctors in Michigan →
Other cardiologists in Grand Rapids
Clinicians with the same Medicare primary specialty in Grand Rapids, MI — not a recommendation.
Clinician information
| Credential | DO |
|---|---|
| Medical school | At Still University Of Health Sciences, College Of Osteo Med, Kirksville |
| Graduation year | 1989 |
| Gender (as listed) | Male |
| Medicare assignment | Accepts (Medicare-approved amount as full payment) |
| NPI (National Provider Identifier) | 1134103732 |
| 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 2026-10-02, retrieved 2026-10-29
- National Downloadable File (Doctors and Clinicians) — CMS, data updated 2026-10-02, retrieved 2026-10-29
- 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