Cholangiopancreatography, Endoscopic RetrogradeClinical CompetenceEndosonography
Dr. Andrew Joseph Walker, MD
NPI1649482605PAC ID8426172313
- Medicare services, 2024
- 733
- Medicare patients, 2024
- 380
- Part D claims, 2024
- 705
- Publications
- 8
- Hospital affiliations
- 4
- Practice address
- 700 South Park St, Madison, WI 53715
- Practice phone
- Call (608) 251-6100
- Professional email
- Get professional email
- Personal email
- Get personal email
- Mobile number
- Get mobile number
Primary practice
Find Dr. Walker's professional email, personal email and mobile number
Dmand AI checks each channel through healthcare-specific waterfall enrichment. See what is on file with a free account, with practice phones, licenses and affiliations.
Dr. Andrew Joseph Walker is a gastroenterologist in Madison, Wisconsin
Dr. Walker practices at SSM Health St. Mary's Hospital - Madison in Madison, Wisconsin, part of SSM Health Care.
Dr. Walker's NPI, 1649482605, was assigned on May 4, 2007. Dr. Walker graduated from Saint Louis University School of Medicine in 2007. Dr. Walker holds Wisconsin license 52357.
NPI and contact details
- NPI
- 1649482605NPI Registry (opens in a new tab)
- Medicare PAC ID
- 8426172313
- NPI enumeration date
- May 4, 2007
- NPI status
- Active
- Accepts Medicare assignment
- Yes
- Offers telehealth
- Yes
- Practice phone
- (608) 251-6100
- Professional email
- Get email
- Personal email
- Get email
- Mobile number
- Get number
- Sex
- Male
- Estimated age
- 45
- Medical school graduation
- 2007
Sources: NPPES NPI Registry (CMS); Dmand AI Professional Profile Data; Dmand AI Affiliation Data; and Doctors and Clinicians National Downloadable File (CMS)
Dr. Andrew Joseph Walker practices at SSM Health St. Mary's Hospital - Madison in Madison, Wisconsin
Dr. Walker's primary practice is SSM Health St. Mary's Hospital - Madison, at 700 South Park St, Madison, WI 53715 in Dane County. The practice phone is (608) 251-6100.
- SSM Health St. Mary's Hospital - Madison700 South Park St, Madison, WI 53715 · Dane CountyPhone(608) 251-6100
Source: Dmand AI Affiliation Data
Dr. Andrew Joseph Walker is affiliated with 4 sites of care and 1 medical group
Dr. Walker's primary practice is SSM Health St. Mary's Hospital - Madison in Madison, Wisconsin, part of SSM Health Care. Dr. Walker is also affiliated with SSM Health St. Clare Hospital - Baraboo. The medical group on file is SSM Health Dean Medical Group. Dmand AI also links Dr. Walker to 2 more hospitals, each named with a free account.
SSM Health St. Clare Hospital - BarabooSSM Health Dean Medical Group2 hospitalsNames with a free account
See all 5 affiliations for Dr. WalkerSources: Dmand AI Affiliation Data; and Dmand AI Org Hierarchy Data
Dmand AI tracks the EHR system at Dr. Andrew Joseph Walker's practice
Dmand AI tracks the electronic health record (EHR) system at each site where Dr. Walker practices, 4 sites in all. Vendor and product names are available with a free account.
| Site | EHR vendor and product |
|---|---|
| SSM Health St. Mary's Hospital - Madison | Available with a free account |
| +3 more affiliated sites | Available with a free account |
Source: Dmand AI Technology Install Data
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Dr. Andrew Joseph Walker is one of 277 gastroenterologists in Wisconsin
Gastroenterology is Dr. Walker's primary specialty in the NPI Registry, under taxonomy code 207RG0100X. Dr. Walker is licensed in Wisconsin.
Specialties and state licenses
- Gastroenterology, WisconsinPrimary
Gastroenterologists near Dr. Walker
Counts of gastroenterologists with a Dmand AI profile, by place and practice. Each opens the list.
277gastroenterologists in Wisconsin42gastroenterologists in Madison9gastroenterologists at SSM Health St. Mary's Hospital - Madison
Sources: NPPES NPI Registry (CMS); Dmand AI Professional Profile Data; and Dmand AI Peer Benchmarks
Dr. Andrew Joseph Walker billed Medicare for 733 services in 2024
CMS data shows 733 Medicare services from Dr. Walker across 19 procedure codes in 2024, for 380 Medicare patients. Medicare paid $64,043 for them.
Medicare services, 2024733
Medicare patients380
Paid by Medicare$64,043
Procedure codes19
Dr. Walker's Medicare services by type, 2023 to 2024
- 2023
- 2024
- Surgery
- 2023: 3502024: 3654%
- Office and hospital visits
- 2023: 1382024: 20347%
- Other services
- 2023: 1802024: 1658%
Where Dr. Walker's Medicare services took place, 2024
- In an office10414%
- In a facility62986%
Dr. Walker compared with the Wisconsin median for gastroenterologists, 2024
- Dr. Walker
- Wisconsin median
- Medicare services
- 733vs 3292.2 times
- Medicare patients
- 380vs 25847% above
- Part D claims
- 560vs 42931% above
Medians across 278 gastroenterologists in Wisconsin with Dmand AI profiles that report each measure.
Dr. Walker's most billed Medicare procedure codes, 2024
CMS publishes codes billed for 11 or more Medicare patients. Each label is the code family; CPT descriptions are licensed by the AMA.
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Medicare shows one payer. Book a meeting to get commercial claims data for Dr. Walker and other gastroenterologists in Wisconsin.
Sources: Medicare Physician & Other Practitioners - by Provider and Service (CMS), 2024 data; and Dmand AI Peer Benchmarks
Dr. Andrew Joseph Walker treated 380 Medicare patients in 2024, average age 72
CMS counts 380 Medicare patients who saw Dr. Walker in 2024. The largest group is 65 to 74, with 214 patients. 69% of them have high cholesterol, and 61% have high blood pressure. 12% are also on Medicaid. Their average risk score is 1.15, where 1.00 is the Medicare average.
Across all payers, Dmand AI patient panel data puts Dr. Walker's median patient age at 64, with 53% women.
Medicare patients, 2024380
Average age72
Average risk score1.15
Also on Medicaid12%
Dr. Walker's Medicare patients by age, 2024
Dr. Walker's Medicare patients by sex, 2024
- Women21156%
- Men16944%
Chronic conditions among Dr. Walker's Medicare patients, 2024
- High cholesterol69%
- High blood pressure61%
- Arthritis37%
- Diabetes26%
- Mood disorders25%
- Anxiety24%
- Ischemic heart disease23%
- Chronic kidney disease22%
Share of Medicare patients with each condition. A patient can have several.
Dr. Walker's patients across all payers
Dmand AI patient panel data covers Medicare, Medicaid and commercial patients.
Patient panel by age, all payers
Median age 64
Patient panel by sex, all payers
- Women53%
- Men47%
Sources: Dmand AI Patient Panel Data; and Medicare Physician & Other Practitioners - by Provider (CMS), 2024 data
Dr. Andrew Joseph Walker wrote 705 Medicare Part D claims in 2024
In 2024, Dr. Walker wrote 705 Medicare Part D claims for 357 patients. 84% of them were for generic drugs. CMS names the drug for 560 of them, across 12 drugs with 11 or more claims each, at $208,418 in total drug cost. In 2023, CMS named 623 claims across 18 drugs.
Part D claims, 2024705
Drugs named by CMS12
Total drug cost$208,418
Part D patients357
Dr. Walker's Part D claims by kind of drug, 2024
- Generic590 claims84%
- Brand-name115 claims16%
Dr. Walker's most prescribed drugs by claims, 2024
CMS names a drug when it has 11 or more claims. Share is of the claims for drugs CMS names.
Drug classes CMS tracks in Dr. Walker's Part D claims, 2024
- Antibiotics4%30 of 705 claims
Share of all Part D claims for each drug class CMS reports on. Classes with no claims are left out.
Part D claims for drugs CMS names, 2023 to 2024
- 2023
- 2024
- Claims for drugs CMS names
- 2023: 6232024: 56010%
Drugs named by CMS: 12 in 2024, 18 in 2023.
Sources: Medicare Part D Prescribers - by Provider and Drug (CMS), 2024 data, released May 6, 2026; and Medicare Part D Prescribers - by Provider (CMS), 2024 data
Dr. Andrew Joseph Walker ranks in the 95th percentile for upper gastrointestinal (gi) endoscopy for acid reflux in Medicare
Dr. Walker accepts Medicare assignment, so Medicare's approved amount is taken as full payment. CMS lists Dr. Walker as offering telehealth. CMS counts 298 procedures of upper gastrointestinal (gi) endoscopy for acid reflux by Dr. Walker, more than 95% of the clinicians it reports for that procedure.
- Accepts Medicare assignment
- Yes
- Offers telehealth
- Yes
Where Dr. Walker ranks in Medicare procedure volume
- Upper gastrointestinal (GI) endoscopy for acid reflux
- 95th percentile298 procedures
- Colonoscopy
- 84th percentile123 procedures
CMS ranks each clinician against every clinician it reports for the same procedure category.
Sources: Doctors and Clinicians National Downloadable File (CMS); and Doctors and Clinicians Utilization Data (CMS)
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Dr. Andrew Joseph Walker has 8 publications on record
Dmand AI links 8 papers to Dr. Walker, published from 2013 to 2017. 2015 was the busiest year, with 2. Dr. Walker has published most often in Endosc Ultrasound. Dr. Walker's most frequent co-authors are Deepak V. Gopal, MD, Anurag Soni, MD and Ahmed Akhter, MD.
Papers8
Years published2013 to 2017
Dr. Walker's papers by year, 2013 to 2017
Dr. Walker's most frequent co-authors
Recent publications by Dr. Walker
Gastrointest Endosc
EatingEquipment and SuppliesEsophagoscopy
AdenomaColonic NeoplasmsColonic Polyps
See who Dr. Walker researches with
Physician Network Discovery turns co-authorship, shared hospitals and shared groups into a map of who Dr. Walker works with, so you can find a warm path to the right gastroenterologists.
Sources: PubMed (National Library of Medicine); and Dmand AI Research Linkage
Dr. Andrew Joseph Walker received $214 in industry payments from 2019 to 2021
CMS Open Payments shows 3 general payments to Dr. Walker from 3 drug and device companies from 2019 to 2021. Food and beverage make up the largest share, 100% of the total. Boston Scientific Corporation paid the most, $121.
General payments to Dr. Walker by program year, 2019 to 2021
Companies that paid Dr. Walker the most, 2019 to 2021
Share is of all general payments to this clinician.
Source: Open Payments (CMS), 2025 data, released July 7, 2026
Dr. Andrew Joseph Walker graduated from Saint Louis University School of Medicine
Dr. Walker graduated from Saint Louis University School of Medicine in 2007.
- Medical school
Source: Dmand AI Professional Profile Data
Sources for Dr. Andrew Joseph Walker's profile data
| Data on this page | Source |
|---|---|
| NPI, name, sex, specialty and licenses | NPPES NPI Registry (CMS) (opens in a new tab)Dmand AI Professional Profile Data |
| Practice locations and phone | Dmand AI Affiliation Data |
| Primary practice, affiliations and health system | Dmand AI Affiliation DataDmand AI Org Hierarchy Data |
| Medicare services and procedure codes | Medicare Physician & Other Practitioners - by Provider and Service (CMS) (opens in a new tab) |
| State medians for the same specialty | Dmand AI Peer Benchmarks |
| Medicare patients and the all-payer patient panel | Dmand AI Patient Panel DataMedicare Physician & Other Practitioners - by Provider (CMS) (opens in a new tab) |
| Part D prescribing | Medicare Part D Prescribers - by Provider and Drug (CMS) (opens in a new tab)Medicare Part D Prescribers - by Provider (CMS) (opens in a new tab) |
| MIPS scores, telehealth, assignment and procedure percentiles | Doctors and Clinicians National Downloadable File (CMS) (opens in a new tab)Doctors and Clinicians Utilization Data (CMS) (opens in a new tab) |
| Publications, topics and co-authors | PubMed (National Library of Medicine) (opens in a new tab)Dmand AI Research Linkage |
| Industry payments | Open Payments (CMS) (opens in a new tab) |
| Training, board certification and memberships | Dmand AI Professional Profile Data |
| EHR at each practice site | Dmand AI Technology Install Data |
| Similar physicians | Dmand AI Affiliation Data |
Data last refreshed October 2026Report an inaccuracyRemove my information
FAQ
Frequently asked questions about Dr. Andrew Joseph Walker
Spotted something out of date? Email hello@dmand.ai and we will check the record. Contact details live in the free trial.
What is Dr. Andrew Joseph Walker's NPI number?
Dr. Andrew Joseph Walker's NPI number is 1649482605. It was assigned on May 4, 2007, and it is active in the NPI Registry.
What kind of doctor is Dr. Andrew Joseph Walker?
Dr. Andrew Joseph Walker is a gastroenterologist in Madison, Wisconsin. The primary specialty in the NPI Registry is Gastroenterology Physician (taxonomy code 207RG0100X).
Where does Dr. Andrew Joseph Walker practice?
Dr. Walker practices at 700 South Park St, Madison, WI 53715. Dr. Walker's primary practice is SSM Health St. Mary's Hospital - Madison in Madison, Wisconsin, part of SSM Health Care. Dmand AI also links Dr. Walker to 2 hospitals.
What is Dr. Andrew Joseph Walker's office phone number?
The practice phone on file for Dr. Walker is (608) 251-6100.
What is Dr. Andrew Joseph Walker's medical license number?
Dr. Walker holds Wisconsin license 52357.
Which hospitals is Dr. Andrew Joseph Walker affiliated with?
Dr. Walker practices at SSM Health St. Mary's Hospital - Madison in Madison, Wisconsin. Dr. Walker is also affiliated with SSM Health St. Clare Hospital - Baraboo. Dmand AI links Dr. Walker to 2 more hospitals.
What medical group is Dr. Andrew Joseph Walker part of?
Dr. Walker is linked to SSM Health Dean Medical Group.
Does Dr. Andrew Joseph Walker accept Medicare?
Yes. CMS data shows Dr. Walker billed Medicare for 733 services in 2024, and Dr. Walker accepts Medicare assignment.
Does Dr. Andrew Joseph Walker offer telehealth?
Yes. The CMS Doctors and Clinicians file lists Dr. Walker as offering telehealth services.
How many Medicare patients does Dr. Andrew Joseph Walker see?
CMS counts 380 Medicare patients who saw Dr. Walker in 2024, with an average age of 72.
Show 7 more questionsShow fewer questions
What services does Dr. Andrew Joseph Walker bill to Medicare?
In 2024, Dr. Walker's most billed Medicare services were medicare service (G0500), surgery: digestive system (45385) and hospital inpatient care (99232).
Where did Dr. Andrew Joseph Walker go to medical school?
Dr. Walker graduated from Saint Louis University School of Medicine in 2007.
What drugs does Dr. Andrew Joseph Walker prescribe most?
In 2024 Medicare Part D data, Dr. Walker's most prescribed drugs by claims were Gavilyte-C, Omeprazole and Pantoprazole Sodium.
Has Dr. Andrew Joseph Walker received payments from drug or device companies?
CMS Open Payments shows $214 in general payments to Dr. Walker from 3 companies from 2019 to 2021. The largest total came from Boston Scientific Corporation.
How long has Dr. Andrew Joseph Walker been practicing?
Dr. Walker graduated from medical school in 2007, 19 years ago.
Does Dr. Andrew Joseph Walker do research?
Dmand AI links 8 publications to Dr. Walker, published from 2013 to 2017.
Who does Dr. Andrew Joseph Walker publish with?
Dr. Walker's most frequent co-authors are Deepak V. Gopal, MD (5 shared papers), Anurag Soni, MD (2 shared papers) and Ahmed Akhter, MD (1 shared paper).
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