2026 NPPES data Internal Medicine Physician NPI 1063599686 MD
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Subbuluxmi Natarajan, MD

Internal Medicine Physician in Watertown, Massachusetts. CMS National Plan and Provider Enumeration System profile including specialty classification, practice address, and Medicare prescribing data when reported.

Federal data — no proprietary rating. PlainDoctor publishes the actual CMS NPPES and Medicare records — NPI registration, specialty, practice location, and prescribing data — without a composite score or editorial opinion on top. Every field traces to a federal source.
Prescribing volume
5K
Medicare Part D claims · 501 beneficiaries · Internal Medicine Physician avg: 3K
Generic prescribing
89%
generic claims · 11% brand-name · higher generic rates reduce patient out-of-pocket costs

What the federal data shows

Subbuluxmi Natarajan, MD filed 4,860 Medicare Part D claims in 2023 as a Internal Medicine Physician in Watertown, Massachusetts, prescribing 89% generic.

5K
Part D claims, 2023
89%
generic prescribing
Likely
board-certified (heuristic)

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.

Subbuluxmi Natarajan, MD's Medicare Part D volume vs every U.S. prescriber

Total Medicare Part D claims, 2023 — across all CMS prescribers nationally

4,860 Top 7% higher than 93% of 1,370,886 prescribers

0–200: 670,926 prescribers (49%). Below this entry. 200–400: 182,923 prescribers (13%). Below this entry. 400–600: 90,619 prescribers (7%). Below this entry. 600–800: 56,224 prescribers (4%). Below this entry. 800–1,000: 40,919 prescribers (3%). Below this entry. 1,000–1,200: 31,827 prescribers (2%). Below this entry. 1,200–1,400: 26,224 prescribers (2%). Below this entry. 1,400–1,600: 21,710 prescribers (2%). Below this entry. 1,600–1,800: 19,072 prescribers (1%). Below this entry. 1,800–2,000: 16,451 prescribers (1%). Below this entry. 2,000–2,200: 213,991 prescribers (16%). This entry sits in this band. This provider 0 2K+ every Part D prescriber (claims/yr), bucketed by value

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.

Source CMS Medicare Part D Prescriber Public Use File · 2023

Board certification likely (heuristic — not verified)

Subbuluxmi Natarajan, MD practices in an ABMS-board-eligible specialty and shows active CMS Medicare participation + 2 hospital affiliations — 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 Subbuluxmi Natarajan, MD?

Quality data not reported

NPI registry status

Active

Issued 11/01/2006

NPI 1063599686

Primary specialty

Internal Medicine Physician

High-volume

172,858 US NPIs in this specialty

Medicare Part D claims

4,860 79% vs specialty avg

2023 prescription claims

Specialty avg: 2,716

Specialty distribution in Massachusetts

How Internal Medicine Physician compares to other specialties among Massachusetts providers

Massachusetts providers

Internal Medicine Physician share within Massachusetts

1. Internal Medicine Physician42%2. Internal medicine21%3. Family medicine17%4. Surgical12%5. Pediatric8%
Internal Medicine Physician share within Massachusetts

Specialty board-certification context

Estimated specialty board-certified rate — Internal Medicine Physician (ABMS / AOA reference)

Quality data not reported
Est. board-certified rate
78%
Internal Medicine Physician ABMS/AOA estimate

Est. board-certified rate (Internal Medicine Physician) — ABMS / AOA estimate

0%100%78%
Est. board-certified rate (Internal Medicine Physician) — ABMS / AOA estimate

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).

Subbuluxmi Natarajan, MD appears in the CMS NPPES registry as a Internal Medicine Physician provider holding MD credentials at 485 ARSENAL ST, Watertown, MA, 02472, with a listed phone of (617) 972-5100. NPI 1063599686 was issued on 11/01/2006. Because NPPES data is self-reported by the provider and refreshed monthly, the address, phone, and specialty reflect what Natarajan most recently submitted to CMS rather than a vetted directory listing, which is why patients should always confirm the practice is still at this location before scheduling.

Medicare Part D records for calendar year 2023 show 4,860 prescription claims written by this provider, covering 501 Medicare beneficiaries and totaling roughly $652K in drug spend, split 11% brand-name and 89% generic by claim count, with an opioid prescribing rate of 1.1%. These figures capture only Medicare Part D — commercial insurance, Medicaid, and cash-pay prescriptions are not included, and any drug-beneficiary cell under 11 is suppressed by CMS for patient privacy.

Internal Medicine Physician is a high-volume specialty nationwide, with 172,858 enrolled providers across 56 states and an average of 2,716 Part D claims per prescriber, so the context for interpreting these metrics differs meaningfully from a primary-care baseline. Important: PlainDoctor is a directory of publicly available government data, not medical advice, a malpractice database, or a quality rating. Inclusion here does not imply a recommendation, and absence of complaints or sanctions on this page does not mean none exist — always verify credentials through the NPPES NPI Registry, your state medical board, and the ABMS or AOA before making healthcare decisions.

Practice Address

485 ARSENAL ST
Watertown, MA 02472

Provider Details

NPI 1063599686
Specialty Internal Medicine Physician
Credentials MD
Gender Female
NPI Issued 11/01/2006

Hospital and facility affiliations

Facilities where Subbuluxmi Natarajan, MD 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.

Atrius Health Inc
Dedham, MA
Rehabilitation Medical Associates PC
Braintree, MA

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 — Massachusetts BORIM 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 ~38K Massachusetts medical licensees in 2023 — they are NOT specific to Subbuluxmi Natarajan, MD. To verify Subbuluxmi Natarajan, MD's current license status, search the BORIM public license lookup directly, or check the Federation of State Medical Boards (FSMB) verification service.

80
Total board actions, Massachusetts 2023
Across 78 cases
2.11
Actions per 1,000 licensees
Massachusetts statewide rate
probation
Most common action type
29 cases

BORIM 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 Massachusetts disciplinary trends page. Cross-checked against FSMB U.S. Medical Regulatory Trends.

Brand vs generic prescribing mix · Typical

Subbuluxmi Natarajan, MD — brand share 11.0%
Specialty average (est.)

11% brand-name claims vs 89% generic, on 4,860 2023 Medicare Part D claims.

The federal Medicare Part D Generic Dispensing Rate national benchmark sits near 90% generic / 10% brand for primary-care prescribers, per CMS Office of the Actuary 2024 estimates. Higher brand share is common in specialty prescribing where generic equivalents are not available.

Medicare Part D Prescribing Data

CMS Medicare Part D prescriber-level data for calendar year 2023.

4,860
Total Claims
$652K
Total Drug Cost
501
Medicare Beneficiaries

Prescribing Breakdown

30-Day Fills
10,480
Total Day Supply
304,716
Brand vs Generic
11% brand / 89% generic
Brand Drug Cost
$487K
Generic Drug Cost
$164K
Opioid Claims
54 (1.1% rate)
Antibiotic Claims
78

Patient Demographics

Average Patient Age
74.2 years
Avg HCC Risk Score
0.98
Gender Split
76% female / 24% male
Age Distribution
<65: 30, 65-74: 240, 75-84: 169, 85+: 62

Top Prescribed Drugs (Medicare Part D)

Top drugs by claim count for calendar year 2023. Based on Medicare Part D data only.

What Subbuluxmi Natarajan, MD prescribes most

Top Medicare Part D drugs by claim count, 2023

claims
Source CMS Medicare Part D Prescriber Public Use File As of 2023
Drug Claims
Atorvastatin Calcium
394
Lisinopril
267
Levothyroxine Sodium
249
Simvastatin
178
Omeprazole
168
Lorazepam
158
Losartan Potassium
146
Amlodipine Besylate
136
Metoprolol Succinate
127
Hydrochlorothiazide
117

* Counts below 11 are suppressed by CMS for patient privacy. Generic names shown where available from CMS Part D data.

Internal Medicine Physician Overview

How Subbuluxmi Natarajan, MD fits within the Internal Medicine Physician landscape nationally.

172,858
Internal Medicine Physician Providers in US
56
States with Internal Medicine Physician
2,716
Avg Claims per Provider

Subbuluxmi Natarajan, MD's 4,860 claims are above the specialty average of 2,716.

Nearby Internal Medicine Physician Providers in Massachusetts

Other clinicians with the same primary specialty enrolled in Massachusetts, drawn from the same CMS NPPES roster as Natarajan.

Compare Internal Medicine Physician nationally: see state-by-state distribution →

Before you book an appointment

Use this federal record as your verification checklist, not as a recommendation.

  • Confirm the NPI record is current in the official CMS registry — providers update their own NPPES details, and moves can lag. Verify this NPI
  • Check the active license and any disciplinary history with the Massachusetts medical board — federal registration is not a license check. Credential verification guide
  • Weigh a second option: compare this provider with a nearby Internal Medicine Physician peer on Medicare volume and prescribing patterns. Compare providers

Medicare Part D and MIPS figures describe practice patterns in federal programs only — they are not quality ratings, and PlainDoctor does not rate, rank, or recommend providers.

Frequently Asked Questions

What is Subbuluxmi Natarajan, MD's specialty?
Subbuluxmi Natarajan, MD specializes in Internal Medicine Physician and practices in Watertown, Massachusetts. Credentials: MD.
How much does Subbuluxmi Natarajan, MD prescribe under Medicare Part D?
In 2023, Subbuluxmi Natarajan, MD wrote 4,860 Medicare Part D claims totaling $652K in drug costs for 501 beneficiaries.
Where is Subbuluxmi Natarajan, MD located?
Subbuluxmi Natarajan, MD is located at 485 ARSENAL ST, Watertown, MA, 02472. Phone: (617) 972-5100.
What is Subbuluxmi Natarajan, MD's NPI number?
Subbuluxmi Natarajan, MD's National Provider Identifier (NPI) is 1063599686, issued on 11/01/2006.
Does Subbuluxmi Natarajan, MD prescribe more brand-name or generic drugs?
Subbuluxmi Natarajan, MD's prescribing is 11% brand-name and 89% generic drugs by claim count, with $487K in brand drug costs.
Does Subbuluxmi Natarajan, MD prescribe opioids?
Yes, Subbuluxmi Natarajan, MD had 54 opioid claims in 2023 with an opioid prescribing rate of 1.1%.
How many Internal Medicine Physician providers are there in the US?
There are 172,858 Internal Medicine Physician providers across 56 states in the US. The average Internal Medicine Physician provider writes 2,716 Medicare Part D claims per year.
What drugs does Subbuluxmi Natarajan, MD prescribe most often?
Based on 2023 Medicare Part D data, Subbuluxmi Natarajan, MD's most frequently prescribed drugs include Atorvastatin Calcium, Lisinopril, Levothyroxine Sodium. This reflects Medicare Part D prescriptions only and does not include commercial insurance or other payer types.
Does Subbuluxmi Natarajan, MD accept Medicare?
Subbuluxmi Natarajan, MD appears in CMS Medicare data with 4,860 Part D claims and 501 Medicare beneficiaries in 2023. Contact the provider's office directly to confirm current Medicare enrollment and accepted plans.
How can I verify Subbuluxmi Natarajan, MD's credentials?
Subbuluxmi Natarajan, MD's NPI is 1063599686 with credentials MD. 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

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