Zachary C. Demma, MD

Medicare activity in 2024

Official CMS public-use data for Zachary C. Demma, 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)206 services
2. Critical care, first 30-74 minutes (99291)124 services
3. Emergency department visit with moderate level of medical decision making (99284)73 services
4. Established patient office or other outpatient visit with moderate level of decision making, if using time, 30 minutes or more (99214)30 services
5. Amplifed dna or rna probe detection of severe acute respiratory syndrome coronavirus 2 (covid-19) antigen (87635)14 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%
• Anxiety52%
• Depression43%
• Ischemic heart disease41%

Hospitals where Zachary C. Demma works

Medicare's Facility Affiliation Data lists Zachary C. Demma 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.

• Cape Cod HospitalHyannis, MA · Acute Care Hospital · Medicare rating: 2 of 5 stars · Emergency services: listed by Medicare · CCN 220012
• South Shore HospitalSouth Weymouth, MA · Acute Care Hospital · Medicare rating: 2 of 5 stars · Emergency services: listed by Medicare · CCN 220100

Practice locations

Addresses where Zachary C. Demma is enrolled with Medicare (CMS data updated October 2, 2026).

• 27 Park StHyannis, MA 02601 (508) 771‑1800
• 55 Fogg RdWeymouth, MA 02190 (781) 792‑4136

Group practices

Medicare enrollment lists Zachary C. Demma as a member of these groups (CMS data updated October 2, 2026).

• Coastal Medical Associates443 clinicians in the group
• Cape Cod Emergency Associates LLP33 clinicians in the group

Specialties

• Emergency Medicineprimary

Find other Emergency Medicine doctors in Massachusetts →

Other emergency medicine doctors in Hyannis

Clinicians with the same Medicare primary specialty in Hyannis, MA — not a recommendation.

• Shant O. Broukian, MD
• Michael J. Hall, MD
• Robert S. Zarum, MD
• William Karalis, DO
• Meredith B. Horton, MD
• Ravi R. Sarpatwari, MD
• Haven W. Spencer, DO
• Julie C. Williams, MD

All emergency medicine doctors in Hyannis →

Other clinicians in Coastal Medical Associates

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

• Kevin J. Sinclair Jr.
• Young H. Kim, MD
• Nicholas Csikesz, MD
• Achilles M. Athanassiou, MD
• Virginia Monsen, CNA
• Kati Bartholomew

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