Dr. Katherine Rose Studer , DMSC, PA-C
Physician Assistant β’ Chicago, IL
125 S Wacker Dr Ste 300
Chicago, IL 606064421
This profile restates public CMS/NPPES data; T-MedInfo gives no medical advice — consult a licensed professional, and call 911 for emergencies.
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Dr. Katherine Studer is listed in NPPES under Physician Assistant.
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NPI assigned on January 25, 2023; this date does not establish years in practice.
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Published CMS data list 637 Medicare Part D prescriptions, including refills, in 2024.
Source: CMS, Medicare Part D Prescribers β by Provider and Drug, 2024. Published rows only; this is not a quality measure.
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Published Part D records, 2024:
- Rosuvastatin Calcium β 87 prescription fills, including refills.
- Atorvastatin Calcium β 48 prescription fills, including refills.
- Levothyroxine Sodium β 44 prescription fills, including refills.
Source: CMS, Medicare Part D Prescribers β by Provider and Drug, 2024. Drug names come from pharmacy claims. Listing a drug here is not an endorsement or a recommendation.
See all 25 records in the table Β· Guide: How to read Medicare Part D prescriber data
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More Part D prescriptions than 85% of clinicians listed under Physician Assistant in Chicago, IL (2024, 651 clinicians with data). Median for this group: 116. Middle half: 41 to 337.
More Part D prescriptions than 75% of clinicians listed under Physician Assistant in Illinois (2024, 2,668 clinicians with data). Median for this group: 203. Middle half: 67 to 595.
Source: CMS, Medicare Part D Prescribers β by Provider and Drug, 2024. Billing and prescribing volume is not a quality rating.
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Medicare Part D prescriptions went from 250 in 2023 to 637 in 2024.
Source: CMS, Medicare Part D Prescribers β by Provider and Drug, 2023β2024.
Practice Location & Contact Primary Location
125 S Wacker Dr Ste 300
Chicago, IL 606064421
Matched by practice address or phone in NPPES. A shared address or phone does not confirm that this clinician works there.
What Public CMS Data Show
Physician Assistant: NPPES taxonomy is a reported classification, not proof of board certification.
30-day fills
1,527 standardized 30-day fills in 2024
CMS converts prescriptions to 30-day supplies so they can be compared. A 90-day prescription counts as about three 30-day fills.
What this does not show: 30-day fills
It is not a count of patients and not a measure of quality.
Part D drug cost
$55,916 in 2024
The total cost of these prescriptions in 2024, paid by Medicare drug plans, patients and other payers together.
It shows the total spending on drugs this clinician prescribed, not what any one patient paid.
What this does not show: Part D drug cost
A higher cost often reflects the type of medicines a specialty uses. It is not your out-of-pocket cost and not a measure of quality.
Source: CMS, Medicare Part D Prescribers β by Provider and Drug, 2024.
Open Payments general payments, program year 2025
All general payments: $1,923.79 across 94 records.
By nature of payment
- Food and Beverage: $1,923.79 across 94 records.
Reporting-company totals (3 largest of 22)
- Corcept Therapeutics: $264.35 across 9 records.
- Eli Lilly and Company: $261.51 across 15 records.
- Novo Nordisk Inc: $247.57 across 9 records.
A reported payment does not necessarily mean the financial relationship is improper and is not a measure of care quality. Clinicians can review and dispute these records.
Source: Calculated by T-MedInfo from CMS Open Payments general-payment records for program year 2025 (published June 30, 2026).
NPI first issued
2023
The year this clinician's National Provider Identifier (NPI) was issued. An NPI is a unique 10-digit ID that US health care providers use for billing.
What this does not show: NPI first issued
NPIs have been issued only since 2005, so this year is not necessarily when the clinician started practicing.
Source: CMS NPPES NPI Registry.
Medicare assignment not listed
CMS data do not show whether this clinician accepts Medicare assignment. This does not mean they do not accept Medicare. Ask the office.
Medicare assignment applies to Original Medicare. It does not tell you whether the clinician is in a Medicare Advantage plan's network, accepts other insurance, or is taking new patients.
Source: CMS Doctors and Clinicians; Medicare.gov, βDoes your provider accept Medicare as full payment?β
No telehealth indicator
CMS shows this indicator only when recent Medicare claims include telehealth services. The clinician may still offer telehealth; ask the office.
Source: CMS, Telehealth Indicator on Medicare Care Compare (fact sheet, January 2023); CMS Doctors and Clinicians.
Can order Medicare-covered services
CMS lists Dr. Studer as eligible to order or refer Medicare Part B clinical laboratory and imaging services, durable medical equipment (DME) and home health services for people with Medicare.
Medicare pays for these items and services only when they are ordered by an eligible clinician.
What this does not show: Can order Medicare-covered services
It does not mean the clinician offers these services directly.
Source: CMS Medicare Fee-For-Service Public Provider Enrollment (PECOS); CMS Order and Referring file.
Compared with the same specialty in Chicago and Illinois
Billing and prescribing volume is not a quality rating.
Medicare Part D prescriptions
More Part D prescriptions than 85% of clinicians listed under Physician Assistant in Chicago, IL (2024, 651 clinicians with data). Median for this group: 116. Middle half: 41 to 337.
More Part D prescriptions than 75% of clinicians listed under Physician Assistant in Illinois (2024, 2,668 clinicians with data). Median for this group: 203. Middle half: 67 to 595.
Part D drug cost
A higher Part D drug cost than 80% of clinicians listed under Physician Assistant in Chicago, IL (2024, 651 clinicians with data). Median for this group: $1,977. Middle half: $320 to $34,048.
A higher Part D drug cost than 75% of clinicians listed under Physician Assistant in Illinois (2024, 2,668 clinicians with data). Median for this group: $3,018. Middle half: $535 to $48,132.
1,446 active clinicians are listed under Physician Assistant with a practice address in Chicago, IL (4,929 in Illinois).
Addresses are self-reported to NPPES and may be out of date.
Telehealth indicator in Chicago
17.4% of these 1,446 clinicians have the CMS telehealth indicator.
63.6% of these 1,446 clinicians are listed by CMS as accepting Medicare assignment.
CMS data by year
Changes may reflect reporting, coverage or privacy limits, not changes in care quality.
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Medicare Part D prescriptions
Medicare Part D prescriptions increased 155% from 250 in 2023 to 637 in 2024.
- 2023: 250
- 2024: 637
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30-day fills
30-day fills increased 169% from 568 in 2023 to 1,527 in 2024.
- 2023: 568
- 2024: 1,527
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Part D drug cost
Part D drug cost increased 1305% from $3,979 in 2023 to $55,916 in 2024.
- 2023: $3,979
- 2024: $55,916
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Industry payments (Open Payments)
Industry payments (Open Payments) increased 64% from $1,169.92 in 2023 to $1,923.79 in 2025.
- 2023: $1,169.92
- 2024: $2,142.47
- 2025: $1,923.79
Sources: CMS Medicare Part D Prescribers (2024), CMS Open Payments (2025), CMS Doctors and Clinicians, CMS NPPES NPI Registry. Specialty names follow the NUCC Health Care Provider Taxonomy.
Text: T-MedInfo Β· Report an error.
Pharma & Medical Device Financial Disclosures
Payments and other transfers of value that drug and medical device companies reported to CMS Open Payments
Program year 2025 (payments made January 1 β December 31, 2025): 94 records totaling $1,923.79.
| Manufacturer | Payment Nature | Product | Type | Amount ($) |
|---|---|---|---|---|
| Corcept Therapeutics |
Food and Beverage
In-kind items and services
|
Korlym | General | $40.65 |
| Corcept Therapeutics |
Food and Beverage
In-kind items and services
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Korlym | General | $35.39 |
| Corcept Therapeutics |
Food and Beverage
In-kind items and services
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Korlym | General | $34.43 |
| ABBVIE INC. |
Food and Beverage
In-kind items and services
|
CREON | General | $34.42 |
| Novo Nordisk Inc |
Food and Beverage
In-kind items and services
|
Wegovy | General | $33.09 |
| Novo Nordisk Inc |
Food and Beverage
In-kind items and services
|
Wegovy | General | $32.68 |
| Novo Nordisk Inc |
Food and Beverage
In-kind items and services
|
β | General | $31.13 |
| Corcept Therapeutics |
Food and Beverage
In-kind items and services
|
Korlym | General | $30.96 |
| Corcept Therapeutics |
Food and Beverage
In-kind items and services
|
Korlym | General | $30.70 |
| Corcept Therapeutics |
Food and Beverage
In-kind items and services
|
Korlym | General | $30.61 |
| Novo Nordisk Inc |
Food and Beverage
In-kind items and services
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Wegovy | General | $28.83 |
| Exact Sciences Corporation |
Food and Beverage
In-kind items and services
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The Cologuard Plus Collection Kit | General | $28.15 |
| Novo Nordisk Inc |
Food and Beverage
In-kind items and services
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Wegovy | General | $27.04 |
| Novo Nordisk Inc |
Food and Beverage
In-kind items and services
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β | General | $26.71 |
| AstraZeneca Pharmaceuticals LP |
Food and Beverage
In-kind items and services
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FARXIGA | General | $26.66 |
| Exact Sciences Corporation |
Food and Beverage
In-kind items and services
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The Cologuard Plus Collection Kit | General | $25.92 |
| Exact Sciences Corporation |
Food and Beverage
In-kind items and services
|
The Cologuard Plus Collection Kit | General | $25.38 |
| Novo Nordisk Inc |
Food and Beverage
In-kind items and services
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β | General | $24.94 |
| Ardelyx, Inc. |
Food and Beverage
In-kind items and services
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IBSRELA | General | $24.83 |
| GlaxoSmithKline, LLC. |
Food and Beverage
In-kind items and services
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TRELEGY ELLIPTA | General | $24.71 |
| Viatris Specialty LLC |
Food and Beverage
In-kind items and services
|
YUPELRI | General | $24.35 |
| Eli Lilly and Company |
Food and Beverage
In-kind items and services
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MOUNJARO | General | $24.11 |
| Eli Lilly and Company |
Food and Beverage
In-kind items and services
|
MOUNJARO | General | $24.05 |
| Bayer Healthcare Pharmaceuticals Inc. |
Food and Beverage
In-kind items and services
|
Kerendia | General | $23.56 |
| Corcept Therapeutics |
Food and Beverage
In-kind items and services
|
Korlym | General | $23.27 |
(top 25 shown)
Source: CMS Open Payments, program year 2025, released June 30, 2026.
Medicare Part D Prescribing Profile & Medications
Medicare Part D prescriptions filled, including refills, in 2024.
| Brand Name | Generic Name | Prescriptions | Day Supply | Total Cost | Patients |
|---|---|---|---|---|---|
| Rosuvastatin Calcium | Rosuvastatin Calcium | 87 | 7,830 | $757.89 | 48 |
| Atorvastatin Calcium | Atorvastatin Calcium | 48 | 3,810 | $320.73 | 18 |
| Levothyroxine Sodium | Levothyroxine Sodium | 44 | 3,606 | $726.96 | 17 |
| Amlodipine Besylate | Amlodipine Besylate | 39 | 3,150 | $291.89 | 21 |
| Telmisartan | Telmisartan | 38 | 3,270 | $844.92 | 19 |
| Pantoprazole Sodium | Pantoprazole Sodium | 35 | 3,030 | $434.24 | 19 |
| Amoxicillin-Clavulanate Potass | Amoxicillin/Potassium Clav | 32 | 305 | $250.49 | 27 |
| Azithromycin | Azithromycin | 31 | 155 | $110.31 | 30 |
| Escitalopram Oxalate | Escitalopram Oxalate | 26 | 2,280 | $550.94 | 12 |
| Hydrochlorothiazide | Hydrochlorothiazide | 25 | 2,130 | $88.26 | 14 |
| Metoprolol Succinate | Metoprolol Succinate | 21 | 1,840 | $431.69 | β |
| Losartan Potassium | Losartan Potassium | 19 | 1,710 | $259.78 | β |
| Methylprednisolone | Methylprednisolone | 18 | 108 | $94.71 | 17 |
| Metformin Hcl Er | Metformin Hcl | 17 | 1,263 | $114.34 | β |
| Olmesartan Medoxomil | Olmesartan Medoxomil | 17 | 1,470 | $495.53 | 12 |
| Albuterol Sulfate Hfa | Albuterol Sulfate | 17 | 601 | $701.61 | 13 |
| Nitrofurantoin Mono-Macro | Nitrofurantoin Monohyd/M-Cryst | 16 | 102 | $210.65 | 14 |
| Gabapentin | Gabapentin | 15 | 1,035 | $325.93 | β |
| Nebivolol Hcl | Nebivolol Hcl | 15 | 1,350 | $1,106.99 | β |
| Allopurinol | Allopurinol | 14 | 1,260 | $142.56 | β |
| Eliquis | Apixaban | 14 | 945 | $18,043.32 | β |
| Ozempic | Semaglutide | 13 | 476 | $13,845.28 | β |
| Fluticasone Propionate | Fluticasone Propionate | 12 | 360 | $119.56 | 12 |
| Farxiga | Dapagliflozin Propanediol | 12 | 840 | $15,378.27 | β |
| Celecoxib | Celecoxib | 12 | 341 | $268.85 | 12 |
Source: CMS Part D by Provider and Drug, 2024; rows below 11 claims omitted by CMS; volume isn’t quality. Privacy limits
Specialties & License Numbers Reported to NPPES
Self-certified to NPPES: 2026-03-26NUCC Taxonomy Code: 363A00000X
A physician assistant is a person who has successfully completed an accredited education program for physician assistant, is licensed by the state and is practicing within the scope of that license. Physician assistants are formally trained to perform many of the routine, time-consuming tasks a physician can do. In some states, they may prescribe medications. They take medical histories, perform physical exams, order lab tests and x-rays, and give inoculations. Most states require that they work under the supervision of a physician.
Medicare (PECOS) Enrollment & Ordering Eligibility
Source: CMS PECOSSources: CMS Provider Enrollment and Order and Referring. Medicare enrollment is a billing status, not an accreditation or quality rating.
Clinicians Sharing This Practice Address or Phone
Clinicians sharing this NPPES address, phone or fax; a shared contact does not mean they work together.
Nurse Practitioner - Family
Family Nurse Practitioner
Family Medicine
Doctor of Medicine (M.D.)
Nurse Practitioner - Family
Nurse Practitioner
Physician Assistant
Physician Assistant (Certified)
Internal Medicine
Doctor of Medicine (M.D.)
Nurse Practitioner - Family
Advanced Practice Registered Nurse, Family Nurse Practitioner (Board Certified)
Career & Practice History Timeline
Changes recorded in monthly NPPES data files: addresses, names, credentials, specialties and NPI status
Registered at 125 S WACKER DR STE 300, CHICAGO, IL 606064421 (Tel: 6175051520)
Registered at 109 STATE ST., 5TH FL, BOSTON, MA 021092906 (Tel: 6175051520)
Recorded as KATHERINE STUDER, DMSC, PA-C
Physician Assistant (license number reported to NPPES: IL 085009316)
Registered at 1850 W WINCHESTER RD STE 220, LIBERTYVILLE, IL 600485355 (Tel: 8473629050)
NPI status registered as active in NPPES database
Registered at 1850 W WINCHESTER RD, STE 220, LIBERTYVILLE, IL 60048 (Tel: 8473629050)
Registered at 15320 WALNUT RD, OAK FOREST, IL 60452 (Tel: 7088451602)
Recorded as KATHERINE CASTILLO, PA
Physician Assistant
First registered as active Individual Practitioner in NPPES Database.
NPI Administrative Meta
Other Physician Assistants in Chicago
- Jenna Jacobson, PA-C
- Carly Martinez, PA-C
- Lisa Werner, PA
- Krista Wunsch, PA-C
- Jessica Jakob
- Arslan Saleem
Mailing Address
109 State St., 5th Fl
Boston, MA 021092906
Phone: 6175051520