NPI registry status
Active
2026 NPPES data Internal Medicine Physician NPI 1336136548 MD
Verify on CMS → Humayun Abbas, MD
Internal Medicine Physician in Modesto, 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 172,858 in Internal 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
17K
Medicare Part D claims · 1K beneficiaries · Internal Medicine Physician avg: 3K
Generic prescribing
90%
generic claims · 10% brand-name · higher generic rates reduce patient out-of-pocket costs
Source: CMS Medicare Part D Prescriber Public Use File, 2023
Compiled from official public sources by the PlainDoctor editorial team.
What the federal data shows
Humayun Abbas, MD filed 16,651 Medicare Part D claims in 2023 as a Internal Medicine Physician in Modesto, California, prescribing 90% generic.
- 17K
- Part D claims, 2023
- 90%
- 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.
Humayun Abbas, MD's Medicare Part D volume vs every U.S. prescriber
Total Medicare Part D claims, 2023, across all CMS prescribers nationally
16,651 Top 2% higher than 98% of 1,370,886 prescribers
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)
Humayun Abbas, MD 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 Humayun Abbas, MD?
Quality data not reportedPrimary specialty
Internal Medicine Physician
Medicare Part D claims
16,651 6× vs specialty avg
Specialty distribution in California
How Internal 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 Internal 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).
Humayun Abbas, MD appears in the CMS NPPES registry as a Internal Medicine Physician provider holding MD credentials at 1541 FLORIDA AVE, Modesto, CA, 95350, with a listed phone of (209) 577-3388. NPI 1336136548 was issued on 10/03/2005.
Medicare Part D records for calendar year 2023 show 16,651 prescription claims written by this provider, covering 1,079 Medicare beneficiaries and totaling roughly $1.4 million in drug spend, split 10% brand-name and 90% generic by claim count, with an opioid prescribing rate of 7.8%.
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
Provider Details
| NPI | 1336136548 |
|---|---|
| Specialty | Internal Medicine Physician |
| Credentials | MD |
| Gender | Male |
| NPI Issued | 10/03/2005 |
Hospital and facility affiliations
Facilities where Humayun Abbas, 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.
Shane Speirs MD PC
Modesto, 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 Humayun Abbas, MD. To verify Humayun Abbas, 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
Humayun Abbas, MD - brand share 10.0%
Internal Medicine Physician average
10% brand-name claims vs 90% generic, on 16,651 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.
16,651
Total Claims
$1.4M
Total Drug Cost
1,079
Medicare Beneficiaries
Prescribing Breakdown
- 30-Day Fills
- 33,251
- Total Day Supply
- 946,709
- Brand vs Generic
- 10% brand / 90% generic
- Brand Drug Cost
- $995K
- Generic Drug Cost
- $379K
- Opioid Claims
- 1,301 (7.8% rate)
- Antibiotic Claims
- 699
Patient Demographics
- Average Patient Age
- 73.1 years
- Avg HCC Risk Score
- 1.45
- Gender Split
- 52% female / 48% male
- Age Distribution
- <65: 126, 65-74: 501, 75-84: 325, 85+: 127
Top Prescribed Drugs (Medicare Part D)
Top drugs by claim count for calendar year 2023. Based on Medicare Part D data only.
What Humayun Abbas, MD prescribes most
Top Medicare Part D drugs by claim count, 2023
- Hydrocodone-Acetam…
Hydrocodone-Acetaminophen
1,027 claims
- Atorvastatin Calcium
Atorvastatin Calcium
796 claims
- Amlodipine Besylate
Amlodipine Besylate
552 claims
- Levothyroxine Sodium
Levothyroxine Sodium
455 claims
- Lisinopril
Lisinopril
443 claims
- Omeprazole
Omeprazole
433 claims
- Gabapentin 408
Gabapentin
408 claims
- Metformin Hcl 407
Metformin Hcl
407 claims
| Drug | Claims |
|---|---|
| Hydrocodone-Acetaminophen Hydrocodone/Acetaminophen | 1,027 |
| Atorvastatin Calcium | 796 |
| Amlodipine Besylate | 552 |
| Levothyroxine Sodium | 455 |
| Lisinopril | 443 |
| Omeprazole | 433 |
| Gabapentin | 408 |
| Metformin Hcl | 407 |
| Alprazolam | 363 |
| Tamsulosin Hcl | 320 |
* 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 Humayun Abbas, 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
Humayun Abbas, MD's 16,651 claims are above the specialty average of 2,716.
Nearby Internal Medicine Physician Providers in California
Other clinicians with the same primary specialty enrolled in California, drawn from the same CMS NPPES roster as Abbas.
Dr. Jacob Aaron
MD
San Francisco, CA
Dr. Alistair Aaronson
MD
Stanford, CA
Dr. Jose Abad.
MD
Sacramento, CA
Dr. Donna Abare
MD
Oakland, CA
Marce Abare
Scotts Valley, CA
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 California 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.
Healthcare Guides
Learn more about finding, verifying, and understanding healthcare providers.
How to Find a Doctor
Step-by-step guide to choosing a provider
Verify Credentials
Check NPI, board certification & license status
Medical Specialties Explained
Who treats what and how specialties differ
Understanding Medicare Claims Data
What prescribing data reveals about a provider
In-Network vs Out-of-Network
How insurance networks affect your costs
Telehealth Guide
Virtual care options and coverage in 2026
Explore California
Frequently Asked Questions
What is Humayun Abbas, MD's specialty? ▼
Humayun Abbas, MD specializes in Internal Medicine Physician and practices in Modesto, California. Credentials: MD.
How much does Humayun Abbas, MD prescribe under Medicare Part D? ▼
In 2023, Humayun Abbas, MD wrote 16,651 Medicare Part D claims totaling $1.4M in drug costs for 1,079 beneficiaries.
Where is Humayun Abbas, MD located? ▼
Humayun Abbas, MD is located at 1541 FLORIDA AVE, Modesto, CA, 95350. Phone: (209) 577-3388.
What is Humayun Abbas, MD's NPI number? ▼
Humayun Abbas, MD's National Provider Identifier (NPI) is 1336136548, issued on 10/03/2005.
Does Humayun Abbas, MD prescribe more brand-name or generic drugs? ▼
Humayun Abbas, MD's prescribing is 10% brand-name and 90% generic drugs by claim count, with $995K in brand drug costs.
Does Humayun Abbas, MD prescribe opioids? ▼
Yes, Humayun Abbas, MD had 1,301 opioid claims in 2023 with an opioid prescribing rate of 7.8%.
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 Humayun Abbas, MD prescribe most often? ▼
Based on 2023 Medicare Part D data, Humayun Abbas, MD's most frequently prescribed drugs include Hydrocodone-Acetaminophen, Atorvastatin Calcium, Amlodipine Besylate. This reflects Medicare Part D prescriptions only and does not include commercial insurance or other payer types.
Does Humayun Abbas, MD accept Medicare? ▼
Humayun Abbas, MD appears in CMS Medicare data with 16,651 Part D claims and 1,079 Medicare beneficiaries in 2023. Contact the provider's office directly to confirm current Medicare enrollment and accepted plans.
How can I verify Humayun Abbas, MD's credentials? ▼
Humayun Abbas, MD's NPI is 1336136548 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
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
Compiled from official public sources by the PlainDoctor editorial team.