2026 NPPES data Internal Medicine Physician NPI 1972589026 M.D.
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DOUGLAS SHELLHORN, M.D.

Internal Medicine Physician in SALISBURY, North Carolina. 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
9K
Medicare Part D claims · 669 beneficiaries · Internal Medicine Physician avg: 3K
Generic prescribing
84%
generic claims · 16% brand-name · higher generic rates reduce patient out-of-pocket costs
Industry payments
$159.58
9 payments · CMS Open Payments (Sunshine Act)

What the federal data shows

DOUGLAS SHELLHORN, M.D. filed 8,850 Medicare Part D claims in 2023 as a Internal Medicine Physician in SALISBURY, North Carolina, prescribing 84% generic.

9K
Part D claims, 2023
84%
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.

DOUGLAS SHELLHORN, M.D.'s Medicare Part D volume vs every U.S. prescriber

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

8,850 Top 2% higher than 98% 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)

DOUGLAS SHELLHORN, M.D. 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 DOUGLAS SHELLHORN, M.D.?

Quality data not reported

NPI registry status

Active

Issued 12/21/2005

NPI 1972589026

Primary specialty

Internal Medicine Physician

High-volume

172,858 US NPIs in this specialty

Medicare Part D claims

8,850 226% vs specialty avg

2023 prescription claims

Specialty avg: 2,716

Specialty distribution in North Carolina

How Internal Medicine Physician compares to other specialties among North Carolina providers

North Carolina providers

Internal Medicine Physician share within North Carolina

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

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).

DOUGLAS SHELLHORN, M.D. appears in the CMS NPPES registry as a Internal Medicine Physician provider holding M.D. credentials at 611 MOCKSVILLE AVE, SALISBURY, NC, 28144, with a listed phone of (704) 633-7220. NPI 1972589026 was issued on 12/21/2005. Because NPPES data is self-reported by the provider and refreshed monthly, the address, phone, and specialty reflect what SHELLHORN 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 8,850 prescription claims written by this provider, covering 669 Medicare beneficiaries and totaling roughly $1.0 million in drug spend, split 16% brand-name and 84% generic by claim count, with an opioid prescribing rate of 1.5%. 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

611 MOCKSVILLE AVE
SALISBURY, NC 28144

Provider Details

NPI 1972589026
Specialty Internal Medicine Physician
Credentials M.D.
Gender Male
NPI Issued 12/21/2005

Hospital and facility affiliations

Facilities where DOUGLAS SHELLHORN, M.D. 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.

ROWAN DIAGNOSTIC CLINIC PA
SALISBURY, NC

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 DOUGLAS SHELLHORN, M.D.. Source: openpaymentsdata.cms.gov.

Total received

$160

Largest payer

Astellas Pharma US 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

DOUGLAS SHELLHORN, M.D. — brand share 16.0%
Specialty average (est.)

16% brand-name claims vs 84% generic, on 8,850 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.

8,850
Total Claims
$1.0M
Total Drug Cost
669
Medicare Beneficiaries

Prescribing Breakdown

30-Day Fills
19,719
Total Day Supply
575,110
Brand vs Generic
16% brand / 84% generic
Brand Drug Cost
$889K
Generic Drug Cost
$147K
Opioid Claims
129 (1.5% rate)
Antibiotic Claims
181

Patient Demographics

Average Patient Age
75.7 years
Avg HCC Risk Score
1.29
Gender Split
58% female / 42% male
Age Distribution
<65: 35, 65-74: 280, 75-84: 246, 85+: 108

Top Prescribed Drugs (Medicare Part D)

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

What DOUGLAS SHELLHORN, M.D. 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
Amlodipine Besylate
424
Levothyroxine Sodium
396
Rosuvastatin Calcium
358
Atorvastatin Calcium
323
Lisinopril
262
Omeprazole
248
Losartan Potassium
228
Pantoprazole Sodium
200
Metformin Hcl
187
Metoprolol Succinate
176

* 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 DOUGLAS SHELLHORN, M.D. 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

DOUGLAS SHELLHORN, M.D.'s 8,850 claims are above the specialty average of 2,716.

Nearby Internal Medicine Physician Providers in North Carolina

Other clinicians with the same primary specialty enrolled in North Carolina, drawn from the same CMS NPPES roster as SHELLHORN.

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

Frequently Asked Questions

What is DOUGLAS SHELLHORN, M.D.'s specialty?
DOUGLAS SHELLHORN, M.D. specializes in Internal Medicine Physician and practices in SALISBURY, North Carolina. Credentials: M.D..
How much does DOUGLAS SHELLHORN, M.D. prescribe under Medicare Part D?
In 2023, DOUGLAS SHELLHORN, M.D. wrote 8,850 Medicare Part D claims totaling $1.0M in drug costs for 669 beneficiaries.
Where is DOUGLAS SHELLHORN, M.D. located?
DOUGLAS SHELLHORN, M.D. is located at 611 MOCKSVILLE AVE, SALISBURY, NC, 28144. Phone: (704) 633-7220.
What is DOUGLAS SHELLHORN, M.D.'s NPI number?
DOUGLAS SHELLHORN, M.D.'s National Provider Identifier (NPI) is 1972589026, issued on 12/21/2005.
Does DOUGLAS SHELLHORN, M.D. prescribe more brand-name or generic drugs?
DOUGLAS SHELLHORN, M.D.'s prescribing is 16% brand-name and 84% generic drugs by claim count, with $889K in brand drug costs.
Does DOUGLAS SHELLHORN, M.D. prescribe opioids?
Yes, DOUGLAS SHELLHORN, M.D. had 129 opioid claims in 2023 with an opioid prescribing rate of 1.5%.
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 DOUGLAS SHELLHORN, M.D. prescribe most often?
Based on 2023 Medicare Part D data, DOUGLAS SHELLHORN, M.D.'s most frequently prescribed drugs include Amlodipine Besylate, Levothyroxine Sodium, Rosuvastatin Calcium. This reflects Medicare Part D prescriptions only and does not include commercial insurance or other payer types.
Does DOUGLAS SHELLHORN, M.D. accept Medicare?
DOUGLAS SHELLHORN, M.D. appears in CMS Medicare data with 8,850 Part D claims and 669 Medicare beneficiaries in 2023. Contact the provider's office directly to confirm current Medicare enrollment and accepted plans.
How can I verify DOUGLAS SHELLHORN, M.D.'s credentials?
DOUGLAS SHELLHORN, M.D.'s NPI is 1972589026 with credentials M.D.. 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