Introduction Research has shown increased health‐care resource use (HRU) among patients with Alzheimer's disease and related disorders (ADRD) well before diagnosis, but the degree to which HRU is correlated with disease severity at the time of initial assessment is not well documented. Methods Retrospective analysis of linked medical records and claims data for three cohorts: mild ADRD (first index Mini‐Mental State Examination MMSE ≥20), moderate/severe ADRD (index MMSE < 20), controls without cognitive impairment. HRU during the pre‐index year was compared using multivariate regressions. Results ADRD cohorts had significantly (P < .01) higher HRU than controls. Compared to mild ADRD patients, moderate/severe ADRD patients had higher rates of hospitalizations (relative risk RR: 1.57), emergency department visits (RR: 1.36), potentially avoidable hospitalizations (RR: 1.72), and accidental falls (RR: 1.58). Discussion HRU before initial assessment increases with disease severity at the time of assessment, highlighting the need for timely evaluation and improved management in the earliest stages of ADRD.