Objective:

To evaluate referral to a specialist by primary care providers (PCPs) or other healthcare providers (HCPs) among people diagnosed with common neurological disorders (ND).

Background:

Timely and accurate diagnoses of NDs, including Alzheimer’s and Parkinson’s disease (AD; PD) and multiple sclerosis (MS), can optimize treatment outcomes. Reasons for variability in referrals are not well understood.

Design/Methods:

This retrospective cohort study analyzed claims data from the deidentified Optum Normative Health Information database between 1/1/2016 and 12/31/2021 (study period). Adults with at least two ICD-9/10-CM AD/PD/MS diagnosis codes from any provider during the study period were included; continuous enrollment criteria were required. The index event was a diagnosis of AD/PD/MS or related disorder from a PCP/other HCP between 1/1/2017 and 12/31/2020. No AD/PD/MS diagnoses in the pre-index period were allowed. Referral cohorts comprised people who received AD/PD/MS diagnoses from specialists (i.e., neurologists, neurosurgeons, psychiatrists, geriatric medicine specialists) post index. Referral rates, time to specialist referral and geographic disparities were reported. US heatmaps of referral proportions were generated using three-digit ZIP codes (ZIP3).

Results:

In the AD cohort, 13,074 of 48,525 people (27%) with index diagnoses from a PCP/other HCP were referred to specialists. In the PD cohort, 13,911 of 26,431 people (53%) were referred to specialists. In the MS cohort, 3391 of 8169 people (42%) were referred to specialists. The median (IQR) times to first specialist visit were 10.0 (3.2–20.7), 5.7 (1.7–15.1) and 2.6 (0.7–10.3) months in AD, PD and MS cohorts, respectively. Referral rates were influenced by age across all three NDs, and certain underrepresented groups were less likely to be referred for AD and PD (P<0.05). ZIP3 heatmaps revealed substantial geographic variation in referrals.

Conclusions:

Referral rates and time to specialist visit varied across people diagnosed with NDs. Demographic and geographic factors additionally influenced specialist referrals.