Richard X. Brennan, MD

Medicare activity in 2024

Official CMS public-use data for Richard X. 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.

Most frequent services

1. Cervical or vaginal cancer screening; pelvic and clinical breast examination (G0101)37 services
2. Established patient office or other outpatient visit with low level od decision making, if using time, 20 minutes or more (99213)20 services
3. Screening papanicolaou smear; obtaining, preparing and conveyance of cervical or vaginal smear to laboratory (Q0091)18 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 cholesterol69%
• High blood pressure53%
• Arthritis42%
• Anxiety31%
• Depression22%
• Diabetes20%

Hospitals where Richard X. Brennan works

Medicare's Facility Affiliation Data lists Richard X. 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.

• Mercy Hospital JeffersonCrystal City, MO · Acute Care Hospital · Medicare rating: 4 of 5 stars · Emergency services: listed by Medicare · CCN 260023
• Mercy Hospital SouthSaint Louis, MO · Acute Care Hospital · Medicare rating: 2 of 5 stars · Emergency services: listed by Medicare · CCN 260077
• Mercy Hospital St LouisSaint Louis, MO · Acute Care Hospital · Medicare rating: 4 of 5 stars · Emergency services: listed by Medicare · CCN 260020

Practice locations

Addresses where Richard X. Brennan is enrolled with Medicare (CMS data updated October 2, 2026).

• 10004 Kennerly Rd, Suite 115aSaint Louis, MO 63128 (314) 849‑3711
• 12700 Southfork RdSaint Louis, MO 63128
• 621 S New Ballas Rd, Suite 189aSaint Louis, MO 63141 (314) 251‑6335
• 621 S New Ballas Rd, Suite 4017bSaint Louis, MO 63141 (314) 872‑9192

Group practices

Medicare enrollment lists Richard X. Brennan as a member of this group (CMS data updated October 2, 2026).

• Mercy Clinic East Communities571 clinicians in the group

Specialties

• Obstetrics/Gynecologyprimary

Find other Obstetrics/Gynecology doctors in Missouri →

Other OB-GYNs in Saint Louis

Clinicians with the same Medicare primary specialty in Saint Louis, MO — not a recommendation.

• Jeremiah Cox, MD
• Barbara Blachut, MD
• Katherine M. Massa, MD
• Thomas R. Whalen, MD
• Sherri L. Jackson, MD
• Shelby M. Dickison, MD
• Gary M. Wasserman, MD
• Hannah M. Vetter, DO

All OB-GYNs in Saint Louis →

Other clinicians in Mercy Clinic East Communities

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

• Yunus Emre Demirhan, MD
• Jeremiah Cox, MD
• Ming Hao, MD
• Christina C. Bearden
• Erin K. Buckley, MD
• Jonnathan Rodriguez, MD

Clinician information

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