2026 NPPES data Gastroenterology Physician NPI 1598843138 MD
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Douglas Corley, MD

Gastroenterology Physician in San Francisco, 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 16,567 in Gastroenterology 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
170
Medicare Part D claims · 38 beneficiaries · Gastroenterology Physician avg: 833
Generic prescribing
76%
generic claims · 24% brand-name · higher generic rates reduce patient out-of-pocket costs
Compiled from official public sources by the PlainDoctor editorial team.

What the federal data shows

Douglas Corley, MD filed 170 Medicare Part D claims in 2023 as a Gastroenterology Physician in San Francisco, California, prescribing 76% generic.

170
Part D claims, 2023
76%
generic prescribing

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

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

170 35th percentile higher than 35% of 1,370,886 prescribers

0–200: 670,926 prescribers (49%). This entry sits in this band. 200–400: 182,923 prescribers (13%). Above this entry. 400–600: 90,619 prescribers (7%). Above this entry. 600–800: 56,224 prescribers (4%). Above this entry. 800–1,000: 40,919 prescribers (3%). Above this entry. 1,000–1,200: 31,827 prescribers (2%). Above this entry. 1,200–1,400: 26,224 prescribers (2%). Above this entry. 1,400–1,600: 21,710 prescribers (2%). Above this entry. 1,600–1,800: 19,072 prescribers (1%). Above this entry. 1,800–2,000: 16,451 prescribers (1%). Above this entry. 2K+: 213,991 prescribers (16%). Above this entry. 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-eligible specialty (heuristic, not verified)

Douglas Corley, MD practices in an ABMS-board-eligible specialty but we don't have enough CMS-participation signals to confirm active board-certified status. Consult CertificationMatters.org (the official ABMS public lookup).

What does the federal data show about Douglas Corley, MD?

Quality data not reported

NPI registry status

Active

Issued 11/01/2006

NPI 1598843138

Primary specialty

Gastroenterology Physician

Mid-sized

16,567 US NPIs in this specialty

Medicare Part D claims

170 80% vs specialty avg

2023 prescription claims

Specialty avg: 833

Specialty distribution in California

How Gastroenterology Physician compares to other specialties among California providers

California providers
Behavior Technician - 17.3%Behavior Technician17.3%Marriage & Family Therapist - 5.5%Marriage & Family Therapist5.5%Student in an Organized Health Care Education/Training Program - 5%Student in an Organized Health Care Education/Training Program5%Mental Health Counselor - 3.9%Mental Health Counselor3.9%Pharmacist - 3.5%Pharmacist3.5%Clinical Social Worker - 3.1%Clinical Social Worker3.1%Gastroenterology Physician - 0.2%Gastroenterology Physician0.2%
Largest specialties in California (% of in-state 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 Gastroenterology Physician. Verify directly:

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 Corley, MD appears in the CMS NPPES registry as a Gastroenterology Physician provider holding MD credentials at 2200 OFARRELL ST, San Francisco, CA, 94115, with a listed phone of (415) 833-2000. NPI 1598843138 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 Corley 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 170 prescription claims written by this provider, covering 38 Medicare beneficiaries and totaling roughly $29K in drug spend, split 24% brand-name and 76% generic by claim count. 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.

Gastroenterology Physician is a mid-sized specialty nationwide, with 16,567 enrolled providers across 54 states and an average of 833 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

2200 OFARRELL ST
San Francisco, CA 94115

Provider Details

NPI 1598843138
Specialty Gastroenterology Physician
Credentials MD
Gender Male
NPI Issued 11/01/2006

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 Douglas Corley, MD. To verify Douglas Corley, MD'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.

Brand vs generic prescribing mix · Typical

Douglas Corley, MD - brand share 24.0%
Gastroenterology Physician average

24% brand-name claims vs 76% generic, on 170 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.

170
Total Claims
$29K
Total Drug Cost
38
Medicare Beneficiaries

Prescribing Breakdown

30-Day Fills
394
Total Day Supply
11,494
Brand vs Generic
24% brand / 76% generic
Brand Drug Cost
$24K
Generic Drug Cost
$5K

Patient Demographics

Average Patient Age
74.1 years
Avg HCC Risk Score
1.50
Gender Split
58% female / 42% male

Top Prescribed Drugs (Medicare Part D)

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

What Douglas Corley, 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
Lialda
Mesalamine
21
Omeprazole
16
Azathioprine
15
Ondansetron Hcl
14

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

Gastroenterology Physician Overview

How Douglas Corley, MD fits within the Gastroenterology Physician landscape nationally.

16,567
Gastroenterology Physician Providers in US
54
States with Gastroenterology Physician
833
Avg Claims per Provider

Douglas Corley, MD's 170 claims are below the specialty average of 833.

Nearby Gastroenterology Physician Providers in California

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

Compare Gastroenterology 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 California medical board, federal registration is not a license check. Credential verification guide
  • Weigh a second option: compare this provider with a nearby Gastroenterology 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 Douglas Corley, MD's specialty?
Douglas Corley, MD specializes in Gastroenterology Physician and practices in San Francisco, California. Credentials: MD.
How much does Douglas Corley, MD prescribe under Medicare Part D?
In 2023, Douglas Corley, MD wrote 170 Medicare Part D claims totaling $29K in drug costs for 38 beneficiaries.
Where is Douglas Corley, MD located?
Douglas Corley, MD is located at 2200 OFARRELL ST, San Francisco, CA, 94115. Phone: (415) 833-2000.
What is Douglas Corley, MD's NPI number?
Douglas Corley, MD's National Provider Identifier (NPI) is 1598843138, issued on 11/01/2006.
Does Douglas Corley, MD prescribe more brand-name or generic drugs?
Douglas Corley, MD's prescribing is 24% brand-name and 76% generic drugs by claim count, with $24K in brand drug costs.
How many Gastroenterology Physician providers are there in the US?
There are 16,567 Gastroenterology Physician providers across 54 states in the US. The average Gastroenterology Physician provider writes 833 Medicare Part D claims per year.
What drugs does Douglas Corley, MD prescribe most often?
Based on 2023 Medicare Part D data, Douglas Corley, MD's most frequently prescribed drugs include Lialda, Omeprazole, Azathioprine. This reflects Medicare Part D prescriptions only and does not include commercial insurance or other payer types.
Does Douglas Corley, MD accept Medicare?
Douglas Corley, MD appears in CMS Medicare data with 170 Part D claims and 38 Medicare beneficiaries in 2023. Contact the provider's office directly to confirm current Medicare enrollment and accepted plans.
How can I verify Douglas Corley, MD's credentials?
Douglas Corley, MD's NPI is 1598843138 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

Compiled from official public sources by the PlainDoctor editorial team.