Dr. Gwendolen Chang, M.D.
What this data tells you about Dr. Chang
Dr. Gwendolen Chang is an internal medicine specialist in San Leandro, CA, with 17 years of NPI registration. Based on federal Medicare data, Dr. Chang performed 1,785 Medicare services across 754 unique beneficiaries.
Between the years covered by Open Payments, Dr. Chang received a total of $3,667 from 28 pharmaceutical and/or device companies across 161 individual payments. These payments are legal, publicly disclosed under the federal Sunshine Act, and common in internal medicine. Most payments are for meals and travel — low-value interactions common across virtually all practicing physicians. Patients may wish to discuss these relationships with their provider.
The Data Coverage level for Dr. Chang is Very High — reflecting how much public federal data is available about this provider. Patients are encouraged to use this data as one of several factors when choosing a healthcare provider.
Medicare Practice Summary
Medicare Utilization ↗Top procedures by volume
Ranked by number of services performed for Medicare patients. Avg. submitted charge is what the provider billed; avg. Medicare payment is what CMS paid.
| Procedure | Volume | Avg. paid | Avg. submitted |
|---|---|---|---|
| Hospital follow-up visit, high complexity Subsequent hospital inpatient or observation care for an existing patient involving high-level medical decision making, with at least 50 minutes total time on the date of the encounter. |
436 | $103 | $262 |
| Office visit, established patient (30-39 min) A follow-up office visit for an existing patient lasting between 30 and 39 minutes. The visit involves medical evaluation and management of the patient's condition. |
376 | $87 | $298 |
| Dialysis services for patients 20 or older Dialysis treatment provided to patients aged 20 years or older, involving four or more physician visits per month. |
301 | $320 | $790 |
| Hospital follow-up visit, moderate complexity Follow-up hospital visit for an existing patient involving moderate medical decision making. The visit requires at least 35 minutes of time spent on the date of service. |
242 | $70 | $174 |
| Hemodialysis, single evaluation A dialysis procedure to filter waste from the blood, performed with a physician's evaluation. |
117 | $63 | $158 |
| Initial hospital admission, high complexity Initial hospital inpatient or observation care for a new patient involving high-level medical decision making, with at least 75 minutes total time on the date of the encounter. |
74 | $154 | $382 |
| Dialysis services for adults, 2-3 visits per month This code covers dialysis services for patients aged 20 or older who have 2 to 3 physician visits per month. |
52 | $269 | $660 |
| New patient office visit (45-59 min) An initial office visit for a new patient lasting between 45 and 59 minutes. This code covers the total time spent by the physician or qualified healthcare professional on the date of the encounter. |
46 | $136 | $384 |
| Initial hospital admission, moderate complexity Initial hospital inpatient or observation care for a new patient involving moderate-level medical decision making, with at least 55 minutes total time on the date of the encounter. |
46 | $118 | $286 |
| Office visit, established patient, complex (40-54 min) An office or outpatient visit for an existing patient lasting between 40 and 54 minutes. This level of service is determined by the total time spent on the date of the encounter. |
41 | $143 | $416 |
| Critical care, first 30-74 min Emergency medical care for a critically ill or injured patient lasting between 30 and 74 minutes. This service involves direct patient care and medical decision making to stabilize the patient. |
30 | $183 | $626 |
| New patient office visit, complex (60-74 min) | 12 | $203 | $506 |
| Telephone medical discussion, 21-30 minutes A telephone conversation with a physician lasting between 21 and 30 minutes. This code covers the time spent discussing medical matters over the phone. |
12 | $102 | $298 |
Industry Payment Transparency
Open Payments through 2024 ↗Payment profile
Industry payments classified by relationship type. Not all payments are equal — research and consulting reflect different relationships than speaking programs or meals.
Payment trend by year
Annual totals from pharmaceutical and medical device companies.
Payments by company (2024)
All-time payments by company (2018-2024) ›
Associated products mentioned in payments ›
Most payments (97%) are for meals and travel — low-value interactions that are common across virtually all practicing physicians.
Geographic Context
0.0 mi
Data Sources
| Provider Registry | ✓ NPPES | Weekly updates |
| Medicare Enrollment | ✓ PECOS | Monthly updates |
| Practice Data | ✓ Medicare Util. | Annual (CY lag) |
| Industry Payments | ✓ Open Payments | CY 2024 |
| Disciplinary History | — Not public | N/A |
This provider has data in 4 of 4 available federal datasets, with a Data Coverage level of Very High. This reflects how much public data is available about a provider. How we calculate this →
Summary
Dr. Chang is a clinical cardiology specialist, with above-average Medicare volume (top 18% in CA), with low-engagement industry engagement in the top 19% of CA peers, with 17 years of NPI registration.
This summary is auto-generated from federal data, describing data availability and patterns. Read our methodology →
Frequently Asked Questions
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All data on this page is sourced verbatim from public federal records published by the U.S. Centers for Medicare & Medicaid Services (CMS): NPPES ↗, Open Payments ↗, Medicare Provider Utilization ↗, and PECOS. Publication is mandated by the Physician Payments Sunshine Act (§6002 ACA, 42 U.S.C. §1320a-7h) and the Freedom of Information Act.
This page is not medical advice, an endorsement, a recommendation, or a quality rating. Data Coverage reflects data completeness — how much federal information exists for this provider — not clinical performance, patient outcomes, or quality of care. Always verify information directly with the provider and consult a licensed clinician before making medical decisions.
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