2026 NPPES data Neurology Physician NPI 1639123938 MD, PHD
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THIEN NGUYEN, MD, PHD

Neurology Physician in ROCKVILLE, Maryland. 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
2K
Medicare Part D claims · 277 beneficiaries · Neurology Physician avg: 1K
Generic prescribing
87%
generic claims · 13% brand-name · higher generic rates reduce patient out-of-pocket costs
MIPS score
75/100
▼ 8 pts below national avg 83.1 · [object Object]
Industry payments
$2.3K
124 payments · CMS Open Payments (Sunshine Act)

What the federal data shows

THIEN NGUYEN, MD, PHD reported a CMS MIPS final score of 75/100 — below the 83.1 national average — and filed 1,567 Medicare Part D claims in 2023.

75/100
MIPS score · -8 vs avg
2K
Part D claims, 2023
87%
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.

THIEN NGUYEN, MD, PHD's MIPS score vs every scored U.S. clinician

CMS Merit-based Incentive Payment System (MIPS) final score, 2023 — the federal quality measure

75 15th percentile higher than 15% of 477,587 scored providers

0–10: 8,684 scored providers (2%). Below this entry. 10–20: 3,008 scored providers (1%). Below this entry. 20–30: 3,069 scored providers (1%). Below this entry. 30–40: 2,746 scored providers (1%). Below this entry. 40–50: 2,928 scored providers (1%). Below this entry. 50–60: 5,882 scored providers (1%). Below this entry. 60–70: 13,906 scored providers (3%). Below this entry. 70–80: 118,074 scored providers (25%). This entry sits in this band. 80–90: 129,887 scored providers (27%). Above this entry. 90–100: 189,403 scored providers (40%). Above this entry. This provider 0 100 every MIPS-scored clinician, bucketed by value

Each bar is a band; taller bars hold more scored providers. 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 Merit-based Incentive Payment System (MIPS) · 2023

Board certification likely (heuristic — not verified)

THIEN NGUYEN, MD, PHD practices in an ABMS-board-eligible specialty and shows active CMS Medicare participation + MIPS quality reporting + 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 THIEN NGUYEN, MD, PHD?

Below national average

NPI registry status

Active

Issued 05/20/2006

NPI 1639123938

Primary specialty

Neurology Physician

Mid-sized

19,866 US NPIs in this specialty

Medicare Part D claims

1,567 20% vs specialty avg

2023 prescription claims

Specialty avg: 1,309

MIPS final score

75/100 8.099999999999994% pts

Above neutral band

vs 83.1 national avg

Specialty distribution in Maryland

How Neurology Physician compares to other specialties among Maryland providers

Maryland providers

Neurology Physician share within Maryland

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

Medicare quality performance — MIPS

THIEN NGUYEN, MD, PHD's 2023 MIPS final score plotted against the Neurology Physician national average

Below national average
MIPS Final Score
75/100
vs 83.1 national avg · 2023 performance year

MIPS final score (Neurology Physician) — 75/100 vs national avg 83.1

0%100%National avg83%75%
MIPS final score (Neurology Physician) — 75/100 vs national avg 83.1

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).

THIEN NGUYEN, MD, PHD appears in the CMS NPPES registry as a Neurology Physician provider holding MD, PHD credentials at 9707 MEDICAL CENTER DR STE 220, ROCKVILLE, MD, 20850, with a listed phone of (240) 477-5973. NPI 1639123938 was issued on 05/20/2006. Because NPPES data is self-reported by the provider and refreshed monthly, the address, phone, and specialty reflect what NGUYEN 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 1,567 prescription claims written by this provider, covering 277 Medicare beneficiaries and totaling roughly $893K in drug spend, split 13% brand-name and 87% generic by claim count, with an opioid prescribing rate of 5.2%. 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. On the CMS Merit-based Incentive Payment System, this provider earned a Final Score of 75/100 for the 2023 performance year, compared with the national average of 83.1.

Neurology Physician is a mid-sized specialty nationwide, with 19,866 enrolled providers across 54 states and an average of 1,309 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

9707 MEDICAL CENTER DR STE 220
ROCKVILLE, MD 20850

Provider Details

NPI 1639123938
Specialty Neurology Physician
Credentials MD, PHD
Gender Male
NPI Issued 05/20/2006

CMS Quality Score (MIPS)

Merit-based Incentive Payment System (MIPS) scores from CMS, 2023 performance year.

75
Final Score
Avg: 83.1

Reporting: Individual

Hospital and facility affiliations

Facilities where THIEN NGUYEN, MD, PHD 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.

SUBURBAN/NRH MEDICAL REHABILITATION INC
BETHESDA, MD

Affiliations sourced from CMS Doctors and Clinicians National Downloadable File; hospital ratings from CMS Hospital General Information dataset (cross-referenced by facility name + state).

Industry payments received (2024) — CMS Open Payments transparency data

The federal Physician Payments Sunshine Act (part of the Affordable Care Act) requires drug and medical-device manufacturers + group purchasing organizations to publicly report payments and other transfers of value to physicians and teaching hospitals. The data below covers 2024 for THIEN NGUYEN, MD, PHD. Source: openpaymentsdata.cms.gov.

Total received

$2.3K

Largest payer

ABBVIE INC.

Most common payment type

Food and Beverage

Industry payments are not necessarily indicators of bias — they include research funding, consulting fees for evidence-based work, royalties for inventions, food at conferences, and similar items. The disclosure exists for transparency. Read our methodology for how we interpret this data.

Brand vs generic prescribing mix · Typical

THIEN NGUYEN, MD, PHD — brand share 13.0%
Specialty average (est.)

13% brand-name claims vs 87% generic, on 1,567 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.

1,567
Total Claims
$893K
Total Drug Cost
277
Medicare Beneficiaries

Prescribing Breakdown

30-Day Fills
3,450
Total Day Supply
102,531
Brand vs Generic
13% brand / 87% generic
Brand Drug Cost
$805K
Generic Drug Cost
$87K
Opioid Claims
82 (5.2% rate)

Patient Demographics

Average Patient Age
76.1 years
Avg HCC Risk Score
1.21
Gender Split
59% female / 41% male
Age Distribution
<65: 25, 65-74: 75, 75-84: 119, 85+: 58

Top Prescribed Drugs (Medicare Part D)

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

What THIEN NGUYEN, MD, PHD 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
Donepezil Hcl
186
Memantine Hcl
143
Carbidopa-Levodopa
Carbidopa/Levodopa
140
Gabapentin
92
Tramadol Hcl
82
Levetiracetam
59
Topiramate
54
Trazodone Hcl
49
Levetiracetam Er
Levetiracetam
39
Duloxetine Hcl
33

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

Neurology Physician Overview

How THIEN NGUYEN, MD, PHD fits within the Neurology Physician landscape nationally.

19,866
Neurology Physician Providers in US
54
States with Neurology Physician
1,309
Avg Claims per Provider

THIEN NGUYEN, MD, PHD's 1,567 claims are above the specialty average of 1,309.

Nearby Neurology Physician Providers in Maryland

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

Compare Neurology Physician nationally: see state-by-state distribution →

Frequently Asked Questions

What is THIEN NGUYEN, MD, PHD's specialty?
THIEN NGUYEN, MD, PHD specializes in Neurology Physician and practices in ROCKVILLE, Maryland. Credentials: MD, PHD.
How much does THIEN NGUYEN, MD, PHD prescribe under Medicare Part D?
In 2023, THIEN NGUYEN, MD, PHD wrote 1,567 Medicare Part D claims totaling $893K in drug costs for 277 beneficiaries.
What is THIEN NGUYEN, MD, PHD's Medicare quality score?
THIEN NGUYEN, MD, PHD has a CMS MIPS Final Score of 75/100. The national average MIPS Final Score is 83.1. Source: CMS Merit-based Incentive Payment System (MIPS) 2023.
Where is THIEN NGUYEN, MD, PHD located?
THIEN NGUYEN, MD, PHD is located at 9707 MEDICAL CENTER DR STE 220, ROCKVILLE, MD, 20850. Phone: (240) 477-5973.
What is THIEN NGUYEN, MD, PHD's NPI number?
THIEN NGUYEN, MD, PHD's National Provider Identifier (NPI) is 1639123938, issued on 05/20/2006.
Does THIEN NGUYEN, MD, PHD prescribe more brand-name or generic drugs?
THIEN NGUYEN, MD, PHD's prescribing is 13% brand-name and 87% generic drugs by claim count, with $805K in brand drug costs.
Does THIEN NGUYEN, MD, PHD prescribe opioids?
Yes, THIEN NGUYEN, MD, PHD had 82 opioid claims in 2023 with an opioid prescribing rate of 5.2%.
How many Neurology Physician providers are there in the US?
There are 19,866 Neurology Physician providers across 54 states in the US. The average Neurology Physician provider writes 1,309 Medicare Part D claims per year.
What drugs does THIEN NGUYEN, MD, PHD prescribe most often?
Based on 2023 Medicare Part D data, THIEN NGUYEN, MD, PHD's most frequently prescribed drugs include Donepezil Hcl, Memantine Hcl, Carbidopa-Levodopa. This reflects Medicare Part D prescriptions only and does not include commercial insurance or other payer types.
Does THIEN NGUYEN, MD, PHD accept Medicare?
THIEN NGUYEN, MD, PHD appears in CMS Medicare data with 1,567 Part D claims and 277 Medicare beneficiaries in 2023. Contact the provider's office directly to confirm current Medicare enrollment and accepted plans.
How can I verify THIEN NGUYEN, MD, PHD's credentials?
THIEN NGUYEN, MD, PHD's NPI is 1639123938 with credentials MD, PHD. 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.
Quality Performance
CMS Merit-based Incentive Payment System (MIPS) — 2023 performance year.
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