DIANA JAO, MD appears in the CMS NPPES registry as a Geriatric Medicine (Internal Medicine) Physician provider holding MD credentials at 222 W 39TH AVE, SAN MATEO, CA, 94403, with a listed phone of (650) 573-2426. NPI 1780683789 was issued on 07/20/2005. Because NPPES data is self-reported by the provider and refreshed monthly, the address, phone, and specialty reflect what JAO 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 4,844 prescription claims written by this provider, covering 439 Medicare beneficiaries and totaling roughly $549K in drug spend, split 11% brand-name and 89% generic by claim count, with an opioid prescribing rate of 2.5%. 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.

Geriatric Medicine (Internal Medicine) Physician is a narrow specialty nationwide, with 4,161 enrolled providers across 52 states and an average of 4,450 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.