NPI registry status
Active
2026 NPPES data Family Medicine Physician NPI 1518321629 DO
Verify on CMS → Caitlin Macmillen, DO
Family Medicine Physician in San Diego, California.
This profile is drawn from the federal National Provider Identifier Registry (CMS NPPES), which lists more than 7 million U.S. healthcare providers - including 147,760 in Family Medicine Physician, and covers specialty classification, practice address, and Medicare Part D prescribing data when reported. According to CMS, every field reflects the provider's official federal registration, see our methodology.
Federal data, no proprietary rating.
We show these CMS records as-is - no composite score, no star rating, no editorial opinion layered on top.
Prescribing volume
920
Medicare Part D claims · 109 beneficiaries · Family Medicine Physician avg: 3K
What the federal data shows
Caitlin Macmillen, DO filed 920 Medicare Part D claims in 2023 as a Family Medicine Physician in San Diego, California.
- 920
- Part D claims, 2023
- Likely
- board-certified (heuristic)
- ≥75th
- pct by Part D claim volume (lower-bound band)
Every figure on this page comes straight from federal CMS records (NPPES, Medicare Part D, MIPS, Open Payments) - no proprietary rating or editorial opinion is applied.
CMS NPPES provider registry desk
NPI 1518321629 · Family Medicine Physician
NPI-10 · ENUM-MID · TAX-MEGA · RX-LIGHT · BOOK-MID · PHOTO-ENUM
- NPI-10 1518321629
- ENUM-MID 2016
- TAX-MEGA 148K Family Medicine
- RX-LIGHT 920
- BOOK-MID 15,933 in California
- PHOTO-ENUM Nehal Aleemuddin · 2016
Caitlin Macmillen, DO's Medicare Part D volume vs every U.S. prescriber
Total Medicare Part D claims, 2023, across all CMS prescribers nationally
920 ≥ 75th percentile 75% of 1,370,886 prescribers are in lower value bands
Each bar is a band; taller bars hold more prescribers. The dashed line + filled bar mark this entry. Hover or tap any bar for its full count, share, and where it sits relative to this entry.
The percentile is a conservative 100-claim band: it counts only prescribers in lower claim-volume bands. Medicare Part D claim volume is activity context, not a quality measure or recommendation. See methodology § corpus placement.
Source CMS Medicare Part D Prescriber Public Use File · 2023
✓
Board certification likely (heuristic, not verified)
Caitlin Macmillen, DO practices in an ABMS-board-eligible specialty and shows active CMS Medicare participation + 1 hospital affiliation - signals consistent with board-certified status. For verified board certification, see CertificationMatters.org (the official ABMS public lookup).
What does the federal data show about Caitlin Macmillen, DO?
Quality data not reportedPrimary specialty
Family Medicine Physician
Medicare Part D claims
920 73% vs specialty avg
Specialty distribution in California
How Family Medicine Physician compares to other specialties among California providers
Board certification
Not published by CMS
CMS does not publish a per-provider board-certification field in NPPES. PlainDoctor does not have a reliable per-specialty certification rate to show for Family Medicine Physician. Verify directly:
How MIPS and board certification work
The Merit-based Incentive Payment System (MIPS) scores providers 0–100 across four performance categories: Quality, Cost, Promoting Interoperability, and Improvement Activities, weighted under 42 CFR §414.1380. Reporting is voluntary for many small practices, so absence of a MIPS score is not a quality signal.
Board certification through an ABMS or AOA member board signals voluntary post-licensure examination plus continuous Maintenance of Certification cycles. Verify any individual provider's status through certificationmatters.org (ABMS) or osteopathic.org (AOA).
Practice Address
Provider Details
| NPI | 1518321629 |
|---|---|
| Specialty | Family Medicine Physician |
| Credentials | DO |
| Gender | Female |
| NPI Issued | 04/06/2016 |
Hospital and facility affiliations
Facilities where Caitlin Macmillen, DO bills Medicare from. Star ratings (1-5) are CMS Hospital Compare's "Hospital overall rating" - a composite of mortality, readmission, patient experience, safety, timely care, and efficient use of medical imaging measures. Source: CMS Care Compare.
Regents OF The University OF California
San Diego, CA
Affiliations sourced from CMS Doctors and Clinicians National Downloadable File; hospital ratings from CMS Hospital General Information dataset (cross-referenced by facility name + state).
License & disciplinary context - California MBC 2023 annual report
Aggregate state board data only, NOT a determination of any individual provider's status. The figures below describe statewide disciplinary activity across all ~150K California medical licensees in 2023 - they are NOT specific to Caitlin Macmillen, DO. To verify Caitlin Macmillen, DO's current license status, search the MBC public license lookup directly, or check the Federation of State Medical Boards (FSMB) verification service.
576
Total board actions, California 2023
Across 556 cases
3.84
Actions per 1,000 licensees
California statewide rate
probation
Most common action type
186 cases
MBC publishes annual disciplinary statistics as part of public-record reporting under each state's Administrative Procedure Act. See the full breakdown by action type and year on the California disciplinary trends page. Cross-checked against FSMB U.S. Medical Regulatory Trends.
Medicare Part D Prescribing Data
CMS Medicare Part D prescriber-level data for calendar year 2023.
920
Total Claims
$150K
Total Drug Cost
109
Medicare Beneficiaries
Prescribing Breakdown
- 30-Day Fills
- 2,152
- Total Day Supply
- 62,390
- Generic Drug Cost
- $27K
- Opioid Claims
- 23 (2.5% rate)
- Antibiotic Claims
- 19
Patient Demographics
- Average Patient Age
- 72.3 years
- Avg HCC Risk Score
- 1.29
- Gender Split
- 64% female / 36% male
Top Prescribed Drugs (Medicare Part D)
Top drugs by claim count for calendar year 2023. Based on Medicare Part D data only.
What Caitlin Macmillen, DO prescribes most
Top Medicare Part D drugs by claim count, 2023
- Atorvastatin Calcium
Atorvastatin Calcium
50 claims
- Levothyroxine Sodium
Levothyroxine Sodium
50 claims
- Losartan Potassium
Losartan Potassium
44 claims
- Diclofenac Sodium
Diclofenac Sodium
31 claims
- Gabapentin
Gabapentin
30 claims
- Amlodipine Besylate
Amlodipine Besylate
26 claims
- Omeprazole
Omeprazole
21 claims
- Lisinopril
Lisinopril
20 claims
| Drug | Claims |
|---|---|
| Atorvastatin Calcium | 50 |
| Levothyroxine Sodium | 50 |
| Losartan Potassium | 44 |
| Diclofenac Sodium | 31 |
| Gabapentin | 30 |
| Amlodipine Besylate | 26 |
| Omeprazole | 21 |
| Lisinopril | 20 |
| Ozempic Semaglutide | 20 |
| Rosuvastatin Calcium | 20 |
* Counts below 11 are suppressed by CMS for patient privacy. Generic names shown where available from CMS Part D data.
Family Medicine Physician Overview
How Caitlin Macmillen, DO fits within the Family Medicine Physician landscape nationally.
147,760
Family Medicine Physician Providers in US
56
States with Family Medicine Physician
3,418
Avg Claims per Provider
Caitlin Macmillen, DO's 920 claims are below the specialty average of 3,418.
Nationwide Family Medicine Physician peers with similar MIPS or enrollment year
Two federal-record peer sets for Macmillen, both outside California so the neighborhoods are not geographic containment.
Same NPPES enumeration year (2016)
Same-specialty clinicians who entered the NPI registry in the same calendar year, outside this state.
Nearby Family Medicine Physician Providers in California
Other clinicians with the same primary specialty enrolled in California, drawn from the same CMS NPPES roster as Macmillen.
One of 15,933 Family Medicine Physician providers enrolled in California, 5 are shown here.
Dr. Omer Aba-Omer
MD
Santa Monica, CA
Dr. Michelle Ababa
MD
Wilmington, CA
Dr. Anna Tzeitel Abalos
MD
Roseville, CA
Dr. Adan Abarca
MD
Anaheim, CA
Dr. Lorraine Abate
M.D.
Sacramento, CA
Compare Family Medicine Physician nationally: see state-by-state distribution →
Frequently Asked Questions
What is Caitlin Macmillen, DO's specialty? ▼
Caitlin Macmillen, DO specializes in Family Medicine Physician and practices in San Diego, California. Credentials: DO.
How much does Caitlin Macmillen, DO prescribe under Medicare Part D? ▼
In 2023, Caitlin Macmillen, DO wrote 920 Medicare Part D claims totaling $150K in drug costs for 109 beneficiaries.
Where is Caitlin Macmillen, DO located? ▼
Caitlin Macmillen, DO is located at 200 WEST ARBOR DRIVE, San Diego, CA, 92103. Phone: (615) 543-2165.
What is Caitlin Macmillen, DO's NPI number? ▼
Caitlin Macmillen, DO's National Provider Identifier (NPI) is 1518321629, issued on 04/06/2016.
Does Caitlin Macmillen, DO prescribe opioids? ▼
Yes, Caitlin Macmillen, DO had 23 opioid claims in 2023 with an opioid prescribing rate of 2.5%.
How many Family Medicine Physician providers are there in the US? ▼
There are 147,760 Family Medicine Physician providers across 56 states in the US. The average Family Medicine Physician provider writes 3,418 Medicare Part D claims per year.
What drugs does Caitlin Macmillen, DO prescribe most often? ▼
Based on 2023 Medicare Part D data, Caitlin Macmillen, DO's most frequently prescribed drugs include Atorvastatin Calcium, Levothyroxine Sodium, Losartan Potassium. This reflects Medicare Part D prescriptions only and does not include commercial insurance or other payer types.
Does Caitlin Macmillen, DO accept Medicare? ▼
Caitlin Macmillen, DO appears in CMS Medicare data with 920 Part D claims and 109 Medicare beneficiaries in 2023. Contact the provider's office directly to confirm current Medicare enrollment and accepted plans.
How can I verify Caitlin Macmillen, DO's credentials? ▼
Caitlin Macmillen, DO's NPI is 1518321629 with credentials DO. You can verify this through the NPPES NPI Registry, check state medical board records, and confirm board certification through the ABMS or AOA.
Data Sources
View source datasets and methodology notes
- Provider Directory
- CMS National Plan and Provider Enumeration System (NPPES), download.cms.gov/nppes, updated monthly. Contains NPI, specialty, credentials, and practice location.
- Specialty Classification
- NUCC Health Care Provider Taxonomy (nucc.org), the industry standard for classifying provider specialties in Medicare and Medicaid billing.
- Prescribing Data
- CMS Medicare Part D Prescriber Public Use File (2023). Includes claims, drug costs, beneficiaries, and opioid prescribing rates.
- Limitations
- Provider data is self-reported to CMS. Prescribing data reflects Medicare Part D only and does not include commercial insurance, Medicaid, or cash prescriptions. Claims below 11 beneficiaries are suppressed by CMS for privacy.
See our complete data methodology for details on how we collect and process government data.
Data as of April 2026 (NPPES) / 2023 (Medicare Part D). Source: Centers for Medicare & Medicaid Services (CMS).
Disclaimer: Data from CMS NPPES and Medicare Part D. PlainDoctor does not rate or rank providers. Provider information is self-reported and may not be current. Always verify information directly with the provider. About · Methodology
Every figure on PlainDoctor is rendered directly from the federal CMS NPPES registry, Medicare Part D, MIPS, and Open Payments records, no number is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of May 2026.