Primary care providers (PCPs) may consider referring patients with cognitive impairment to clinicians specializing in memory care. We evaluated whether referrals are associated with quality-of-care and diagnostic outcomes, comparing estimates based on traditional and instrumental variables (IV) analyses. Analyses included individuals diagnosed with memory loss, mild cognitive impairment, or Alzheimer's disease and related dementias (ADRD) in a single healthcare system after 2005. Electronic health records were used to define referral to specialists and PCP preference (instrument) for referring. We modeled traditional and IV associations between referral to care and 14 patient-centered outcomes over 5 years of follow-up using adjusted Aalen additive hazards models. Overall, 1019 (15%) older adults were referred at diagnosis. Preference strongly predicted actual referral (F-statistic = 637). Referral was observationally associated with increased cumulative hazard of receiving a more specific cognitive diagnosis (hazard difference at year 5: 0.09, 95% CI: 0.04-0.15) and depression (0.09, 95% CI, 0.01-0.18). Using IV, referral was significantly associated with decreased hazard of ICD-defined weight loss (-0.35, 95% CI: -0.60,-0.09); other estimates were imprecise and consistent with possible benefits or harms. Given barriers in accessing specialty care, it is critical to further investigate how specialty care affects outcomes of individuals with living with cognitive impairment.
Ferguson et al. (2026) studied this question.