Quick answers
- Does Douglas M. Horst accept Medicare assignment?
- Yes. Medicare's clinician data says Douglas M. Horst 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 Douglas M. Horst see?
- In 2024, CMS data shows 419 Original Medicare patients and 728 services for Douglas M. Horst. This counts Original Medicare only and measures volume, not quality.
- What is Douglas M. Horst's NPI number?
- 1518957224. 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 Douglas M. Horst, 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 patients | 419 |
|---|---|
| Services billed to Medicare | 728 |
| Different services or procedures | 32 |
| Participating Medicare provider | Yes |
| Average age of these patients | 73 |
Most frequent services
- Removal of polyps or growths of large bowel using an endoscope with mechanical snare (45385)93 services
- Visit complexity inherent to evaluation and management associated with medical care services that serve as the continuing focal point for all needed health care services and/or with medical care services that are part of ongoing care related to a patient's (G2211)92 services
- Established patient office or other outpatient visit with low level od decision making, if using time, 20 minutes or more (99213)81 services
- Moderate sedation services provided by the same physician or other qualified health care professional performing a gastrointestinal endoscopic service that sedation supports, requiring the presence of an independent trained observer to assist in the monito (G0500)80 services
- Biopsy of large bowel using a flexible endoscope (45380)78 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 cholesterol72%
- High blood pressure68%
- Arthritis43%
- Anxiety28%
- Ischemic heart disease24%
- Depression23%
Hospitals where Douglas M. Horst works
Medicare's Facility Affiliation Data lists Douglas M. Horst 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.
- Beth Israel Deaconess Hospital - MiltonMilton, MA · Acute Care Hospital · Medicare rating: 4 of 5 stars · Emergency services: listed by Medicare · CCN 220108
- Beth Israel Deaconess Medical CenterBoston, MA · Acute Care Hospital · Medicare rating: 3 of 5 stars · Emergency services: listed by Medicare · CCN 220086
- Massachusetts General HospitalBoston, MA · Acute Care Hospital · Medicare rating: 5 of 5 stars · Emergency services: listed by Medicare · CCN 220071
- Nantucket Cottage HospitalNantucket, MA · Acute Care Hospital · Medicare rating: 3 of 5 stars · Emergency services: listed by Medicare · CCN 220177
Practice locations
Addresses where Douglas M. Horst is enrolled with Medicare (CMS data updated October 2, 2026).
- 330 Brookline AveBoston, MA 02215 (617) 754‑8612
- 57 Prospect StNantucket, MA 02554 (508) 825‑8100
Group practices
Medicare enrollment lists Douglas M. Horst as a member of these groups (CMS data updated October 2, 2026).
- Harvard Medical Faculty Phys at Beth Israel Deaconess Med Ctr Inc1,740 clinicians in the group
- Nantucket Cottage Hospital87 clinicians in the group
Specialties
- Internal Medicineprimary
- Gastroenterologyalso
Other internal medicine doctors in Boston
Clinicians with the same Medicare primary specialty in Boston, MA — not a recommendation.
Other clinicians in Harvard Medical Faculty Phys at Beth Israel Deaconess Med Ctr Inc
Medicare enrollment lists these clinicians in the same group practice — not a recommendation.
Clinician information
| Credential | MD |
|---|---|
| Medical school | University Of California, San Francisco School Of Medicine |
| Graduation year | 1974 (52 years since medical school) |
| Gender (as listed) | Male |
| Medicare assignment | Accepts (Medicare-approved amount as full payment) |
| Telehealth | Offers telehealth services |
| NPI (National Provider Identifier) | 1518957224 |
| Corrections | Report 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
- Facility Affiliation Data — Centers for Medicare & Medicaid Services (CMS), data updated October 2, 2026, retrieved October 29, 2026
- Hospital General Information — CMS, data updated October 26, 2026, retrieved November 13, 2026
- National Downloadable File (Doctors and Clinicians) — CMS, data updated October 2, 2026, retrieved October 29, 2026
- Medicare Physician & Other Practitioners - by Provider — CMS, data year 2024, released May 21, 2026; Medicare Physician & Other Practitioners - by Provider and Service
- NPI Registry — U.S. Department of Health and Human Services (NPPES), the clinician’s official record
- Medicare Care Compare — official Medicare tool to look up clinicians