Warren Joseph A. San Diego, MD

Medicare activity in 2024

Official CMS public-use data for Warren Joseph A. San Diego, 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. Subsequent hospital care with moderate levelof medical decision making, if using time, at least 50 minutes (99233)493 services
2. Hospital discharge day management, more than 30 minutes (99239)184 services
3. Subsequent hospital care with moderate levelof medical decision making, if using time, at least 35 minutes (99232)127 services
4. Initial hospital care with moderate level of medical decision making, if using time, at least 75 minutes (99223)32 services
5. Critical care, first 30-74 minutes (99291)13 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%
• Arthritis56%
• Chronic kidney disease55%
• Diabetes53%
• Heart failure47%

Hospitals where Warren Joseph A. San Diego works

Medicare's Facility Affiliation Data lists Warren Joseph A. San Diego 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.

• NorthBay Medical CenterFairfield, CA · Acute Care Hospital · Medicare rating: 2 of 5 stars · Emergency services: listed by Medicare · CCN 050367

Practice locations

Addresses where Warren Joseph A. San Diego is enrolled with Medicare (CMS data updated October 2, 2026).

• 1200 B Gale Wilson BlvdFairfield, CA 94533 (707) 429‑3600

Group practices

Medicare enrollment lists Warren Joseph A. San Diego as a member of this group (CMS data updated October 2, 2026).

• NorthBay Physicians Surgery Center, LLC324 clinicians in the group

Specialties

• Internal Medicineprimary

Find other Internal Medicine doctors in California →

Other internal medicine doctors in Fairfield

Clinicians with the same Medicare primary specialty in Fairfield, CA — not a recommendation.

• Cassandra Whitmore, MD
• Angeli B. Duran, DO
• Myra B. Noorzay, MD
• Namrita Boparai, MD
• Charbel J. Nadra, MD
• Jonathan Valeriote, MD
• Eric J. Crisostomo, MD
• Gurpreet Dhugga, MD

All internal medicine doctors in Fairfield →

Other clinicians in NorthBay Physicians Surgery Center, LLC

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

• Rachel M. Villalon, MD
• Manrajan S. Gill, MD
• Cyrus Mancherje, MD
• Takara M. Dickson, PA
• Paula Akin, MD
• Ankit Dubey, 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