2026 NPPES data Nephrology Physician NPI 1134144504 M.D.
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JOSEPH OYAMA, M.D.

Nephrology Physician in EVERGREEN PARK, Illinois. 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
11
Medicare Part D claims · Nephrology Physician avg: 1K
What the federal data reveals: JOSEPH OYAMA, M.D. is a Nephrology Physician ([object Object]) practicing in EVERGREEN PARK, Illinois with a Medicare Part D prescribing footprint of 11 claims .

What stands out: JOSEPH OYAMA, M.D. filed 11 Medicare Part D claims in 2023 across EVERGREEN PARK, Illinois. Every figure on this page comes straight from federal CMS records, with no proprietary rating applied.

Board-eligible specialty (heuristic — not verified)

JOSEPH OYAMA, M.D. 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).

JOSEPH OYAMA, M.D. at a glance

Quality data not reported

NPI registry status

Active

Issued 07/13/2006

NPI 1134144504

Primary specialty

Nephrology Physician

Mid-sized

10,534 US NPIs in this specialty

Medicare Part D claims

11 99% vs specialty avg

2023 prescription claims

Specialty avg: 1,454

Specialty distribution in Illinois

How Nephrology Physician compares to other specialties among Illinois providers

Illinois providers

Nephrology Physician share within Illinois

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

Specialty board-certification context

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

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

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

0%100%78%
Est. board-certified rate (Nephrology 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).

JOSEPH OYAMA, M.D. is a Nephrology Physician provider practicing in EVERGREEN PARK, Illinois, according to the CMS National Plan and Provider Enumeration System (NPPES). Credentials: M.D.. NPI: 1134144504. This profile includes practice location, specialty classification, and organizational affiliations from the CMS provider registry. Provider information is self-reported to CMS and updated monthly.

JOSEPH OYAMA, M.D. appears in the CMS NPPES registry as a Nephrology Physician provider holding M.D. credentials at 3650 W 95TH ST, EVERGREEN PARK, IL, 60805, with a listed phone of (708) 422-7715. NPI 1134144504 was issued on 07/13/2006. Because NPPES data is self-reported by the provider and refreshed monthly, the address, phone, and specialty reflect what OYAMA 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 11 prescription claims written by this provider, covering N/A Medicare beneficiaries and totaling roughly $59 in drug spend. 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.

Nephrology Physician is a mid-sized specialty nationwide, with 10,534 enrolled providers across 55 states and an average of 1,454 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

3650 W 95TH ST
EVERGREEN PARK, IL 60805

Provider Details

NPI 1134144504
Specialty Nephrology Physician
Credentials M.D.
Gender Male
NPI Issued 07/13/2006

License & disciplinary context — Illinois IDFPR 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 ~42K Illinois medical licensees in 2023 — they are NOT specific to JOSEPH OYAMA, M.D.. To verify JOSEPH OYAMA, M.D.'s current license status, search the IDFPR public license lookup directly, or check the Federation of State Medical Boards (FSMB) verification service.

106
Total board actions, Illinois 2023
Across 103 cases
2.52
Actions per 1,000 licensees
Illinois statewide rate
probation
Most common action type
38 cases

IDFPR 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 Illinois disciplinary trends page. Cross-checked against FSMB U.S. Medical Regulatory Trends.

Medicare Part D Prescribing Data

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

11
Total Claims
$59
Total Drug Cost
N/A
Medicare Beneficiaries

Prescribing Breakdown

30-Day Fills
29
Total Day Supply
832
Brand Drug Cost
$0
Generic Drug Cost
$59

Patient Demographics

Average Patient Age
84.0 years
Avg HCC Risk Score
0.55

Nephrology Physician Overview

How JOSEPH OYAMA, M.D. fits within the Nephrology Physician landscape nationally.

10,534
Nephrology Physician Providers in US
55
States with Nephrology Physician
1,454
Avg Claims per Provider

JOSEPH OYAMA, M.D.'s 11 claims are below the specialty average of 1,454.

Nearby Nephrology Physician Providers in Illinois

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

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

Frequently Asked Questions

What is JOSEPH OYAMA, M.D.'s specialty?
JOSEPH OYAMA, M.D. specializes in Nephrology Physician and practices in EVERGREEN PARK, Illinois. Credentials: M.D..
How much does JOSEPH OYAMA, M.D. prescribe under Medicare Part D?
In 2023, JOSEPH OYAMA, M.D. wrote 11 Medicare Part D claims totaling $59 in drug costs for N/A beneficiaries.
Where is JOSEPH OYAMA, M.D. located?
JOSEPH OYAMA, M.D. is located at 3650 W 95TH ST, EVERGREEN PARK, IL, 60805. Phone: (708) 422-7715.
What is JOSEPH OYAMA, M.D.'s NPI number?
JOSEPH OYAMA, M.D.'s National Provider Identifier (NPI) is 1134144504, issued on 07/13/2006.
How many Nephrology Physician providers are there in the US?
There are 10,534 Nephrology Physician providers across 55 states in the US. The average Nephrology Physician provider writes 1,454 Medicare Part D claims per year.
Does JOSEPH OYAMA, M.D. accept Medicare?
JOSEPH OYAMA, M.D. appears in CMS Medicare data with 11 Part D claims and N/A Medicare beneficiaries in 2023. Contact the provider's office directly to confirm current Medicare enrollment and accepted plans.
How can I verify JOSEPH OYAMA, M.D.'s credentials?
JOSEPH OYAMA, M.D.'s NPI is 1134144504 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