Joanna S. Maack, MD

Medicare activity in 2024

Official CMS public-use data for Joanna S. Maack, 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. Emergency department visit with high level of medical decision making (99285)100 services
2. New patient office or other outpatient visit with moderate level of medical decision making, if using time, 45 minutes or more (99204)58 services
3. Established patient office or other outpatient visit with moderate level of decision making, if using time, 30 minutes or more (99214)53 services
4. Routine electrocardiogram (ecg) using at least 12 leads with interpretation and report only (93010)28 services
5. Emergency department visit with moderate level of medical decision making (99284)21 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%
• Arthritis62%
• Ischemic heart disease36%
• Diabetes33%
• Anxiety29%

Hospitals where Joanna S. Maack works

Medicare's Facility Affiliation Data lists Joanna S. Maack 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.

• Huntington HospitalPasadena, CA · Acute Care Hospital · Emergency services: listed by Medicare · CCN 050438

Practice locations

Addresses where Joanna S. Maack is enrolled with Medicare (CMS data updated October 2, 2026).

• 100 W California BlvdPasadena, CA 91105
• 26777 Agoura Rd, Suite B4Calabasas, CA 91302 (818) 880‑2225

Group practices

Medicare enrollment lists Joanna S. Maack as a member of these groups (CMS data updated October 2, 2026).

• Exer Medical Corporation340 clinicians in the group
• HMH Emergency Medical Group, Inc.60 clinicians in the group

Specialties

• Emergency Medicineprimary

Find other Emergency Medicine doctors in California →

Other emergency medicine doctors in Pasadena

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

• John Bosco, MD
• Jay B. Slutsky, DO
• Christina Cantwell, MD
• Brandon Libby, MD
• Pauline Holmberg, MD
• Victor Lei, MD
• Timothy C. Lin, DO
• Amy L. Peng, MD

All emergency medicine doctors in Pasadena →

Other clinicians in Exer Medical Corporation

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

• Angelica N. McPartlin, MD
• Charienez S. Cruz, NP
• Ashley Kauth, NP
• Tho H. Nguyen, PA
• Michael Allen, DO
• Akila Arous, PA

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