William S. Sun

William Sun practices at Adventist Health Simi Valley in Simi Valley, California, part of Adventist Health.

William Sun's NPI, 1649777616, was assigned on April 6, 2018. William Sun holds California license A174650.

William Sun's primary practice is Adventist Health Simi Valley, at 2975 N Sycamore Dr, Simi Valley, CA 93065 in Ventura County. The practice phone is (805) 955-6000.

William Sun's primary practice is Adventist Health Simi Valley in Simi Valley, California, part of Adventist Health. William Sun is also affiliated with Santa Clara Valley Medical Center. The medical group on file is Vituity. Dmand AI also links William Sun to 3 more hospitals, 3 medical groups and 1 group practice or clinic, each named with a free account.

Dmand AI tracks the electronic health record (EHR) system at each site where William Sun practices, 6 sites in all. Vendor and product names are available with a free account.

Internal medicine is William Sun's primary specialty in the NPI Registry, under taxonomy code 207R00000X. William Sun is licensed in California.

CMS data shows 176 Medicare services from William Sun across 4 procedure codes in 2024, for 62 Medicare patients. Medicare paid $13,239 for them. Every service was in a facility, such as a hospital, rather than an office.

CMS counts 62 Medicare patients who saw William Sun in 2024. The largest group is 75 to 84, with 22 patients. 75% of them have high blood pressure, and 71% have high cholesterol. 34% are also on Medicaid. Their average risk score is 1.84, where 1.00 is the Medicare average, so they are sicker than most Medicare patients.

Across all payers, Dmand AI patient panel data puts William Sun's median patient age at 65, with 53% women.

In 2024, William Sun wrote 297 Medicare Part D claims for 135 patients. 85% of them were for generic drugs. CMS names the drug for 94 of them, across 6 drugs with 11 or more claims each, at $705 in total drug cost. In 2023, CMS named 65 claims across 5 drugs.

CMS publishes a Merit-based Incentive Payment System (MIPS) score of 82 out of 100 for William Sun for performance year 2024, reported as part of a group. William Sun accepts Medicare assignment, so Medicare's approved amount is taken as full payment.

CMS Open Payments shows 1 general payment to William Sun from 1 drug or device company in 2025. Food and beverage make up the largest share, 100% of the total. AtriCure, Inc. paid the most, $27.