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Hospitalist

Kevin J. O Leary, MD

Works at hospitals in Chicago, IL · Illinois

Summary

Dr. Kevin J. O Leary, MD is a hospitalist at 251 E Huron, Chicago, IL 60611. Accepts Medicare assignment. In 2024, Kevin J. O Leary had 31 Original Medicare patients and 107 services. NPI 1902837537. Source: CMS National Downloadable File, updated October 2, 2026; CMS Facility Affiliation Data, updated October 2, 2026; CMS Medicare Physician & Other Practitioners, data year 2024.

  • Specialty: Hospitalist
  • Address: 251 E Huron, Chicago, IL 60611 · Directions (3 more locations)
  • Medicare: Accepts Medicare assignment
  • Hospital: Northwestern Memorial Hospital
  • Group practice: Northwestern Medical Faculty Foundation
  • Medical school: University Of Illinois College Of Med (chi/peor/rock/chm-Urb) · graduated 1997 (29 years since medical school)
  • Gender (as listed): Male

From official Medicare data

This page shows what Medicare's official clinician data says about Kevin J. O Leary, joined by NPI number (data updated October 2, 2026). It is not a recommendation or a rating. Call the office or hospital to confirm before you go.

In a medical emergency, call 911.

Quick answers

Does Kevin J. O Leary accept Medicare assignment?
Yes. Medicare's clinician data says Kevin J. O Leary 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 Kevin J. O Leary see?
In 2024, CMS data shows 31 Original Medicare patients and 107 services for Kevin J. O Leary. This counts Original Medicare only and measures volume, not quality.
What is Kevin J. O Leary's NPI number?
1902837537. 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 Kevin J. O Leary, 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 patients31
Services billed to Medicare107
Different services or procedures7
Participating Medicare providerYes
Average age of these patients72

Most frequent services

  1. Subsequent hospital care with moderate levelof medical decision making, if using time, at least 35 minutes (99232)53 services
  2. Subsequent hospital care with moderate levelof medical decision making, if using time, at least 50 minutes (99233)27 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%
  • Ischemic heart disease58%
  • Diabetes55%
  • Heart failure55%

Hospitals where Kevin J. O Leary works

Medicare's Facility Affiliation Data lists Kevin J. O Leary 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.

Practice locations

Addresses where Kevin J. O Leary is enrolled with Medicare (CMS data updated October 2, 2026).

Group practices

Medicare enrollment lists Kevin J. O Leary as a member of this group (CMS data updated October 2, 2026).

  • Northwestern Medical Faculty Foundation4,503 clinicians in the group

Specialties

Find other Hospitalist doctors in Illinois →

Other hospitalists in Chicago

Clinicians with the same Medicare primary specialty in Chicago, IL — not a recommendation.

All hospitalists in Chicago →

Other clinicians in Northwestern Medical Faculty Foundation

Medicare enrollment lists these clinicians in the same group practice — not a recommendation.

Clinician information

CredentialMD
Medical schoolUniversity Of Illinois College Of Med (chi/peor/rock/chm-Urb)
Graduation year1997 (29 years since medical school)
Gender (as listed)Male
Medicare assignmentAccepts (Medicare-approved amount as full payment)
NPI (National Provider Identifier)1902837537
CorrectionsReport 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

  1. Facility Affiliation Data — Centers for Medicare & Medicaid Services (CMS), data updated October 2, 2026, retrieved October 29, 2026
  2. Hospital General Information — CMS, data updated October 26, 2026, retrieved November 13, 2026
  3. National Downloadable File (Doctors and Clinicians) — CMS, data updated October 2, 2026, retrieved October 29, 2026
  4. Medicare Physician & Other Practitioners - by Provider — CMS, data year 2024, released May 21, 2026; Medicare Physician & Other Practitioners - by Provider and Service
  5. NPI Registry — U.S. Department of Health and Human Services (NPPES), the clinician’s official record
  6. Medicare Care Compare — official Medicare tool to look up clinicians