MARISSA NIEMEYER, MSN, AGPCNP-C appears in the CMS NPPES registry as a Gerontology Nurse Practitioner provider holding MSN, AGPCNP-C credentials at 145 MICHIGAN ST NE STE 3410, GRAND RAPIDS, MI, 49503, with a listed phone of (616) 391-9945. NPI 1003485194 was issued on 06/22/2021. Because NPPES data is self-reported by the provider and refreshed monthly, the address, phone, and specialty reflect what NIEMEYER 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 4,058 prescription claims written by this provider, covering 176 Medicare beneficiaries and totaling roughly $570K in drug spend, split 23% brand-name and 77% generic by claim count, with an opioid prescribing rate of 3.2%. 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.

Gerontology Nurse Practitioner is a mid-sized specialty nationwide, with 9,625 enrolled providers across 54 states and an average of 1,283 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.