Abstract Body (Do not enter title and authors here): Introduction: Early diagnosis of transthyretin cardiac amyloidosis (ATTR-CM) is integral to the success of effective treatment. While prior studies have explored sociodemographic disparities in diagnostic delays, the impact of telehealth use on ATTR-CM disease severity at the time of diagnosis has not been thoroughly explored.

Hypothesis: Telehealth use before or on date of diagnosis may be associated with earlier ATTR-CM disease stage. This association may vary based on socioeconomic factors, race, or distance traveled to the clinic.

Methods: A total of 438 patients with confirmed ATTR-CM were retrospectively analyzed from the Stanford ATTR-CM database. Telehealth use was defined as ≥1 telehealth visit before or on the date of diagnosis; all visit types were recorded, then categorized for descriptive analysis. To examine the association between telehealth use and disease severity, Columbia stage (early, intermediate, late) was modeled using an ordinal logistic regression. Other models tested covariates, stratified by social deprivation index (SDI), race, and distance from the clinic.

Results: Of the 438 patients, 43% were diagnosed at early, 47% at intermediate and 10% at late stage. Telehealth use was recorded in 33% of patients; among them, 77% had a cardiology, 14% a neurology, and 14% an orthopedic visit, with overlap in categories.

After adjusting for demographics (age, sex, race), distance traveled, and SDI, telehealth use was significantly associated with decreased odds of being diagnosed at a later Columbia stage (OR=0.52, 95% CI: 0.35–0.79, p=0.002). In SDI-stratified models, this association was significant across both low-SDI (OR=0.63, 95% CI: 0.41–0.98, p=0.040) and high-SDI (>80th percentile) areas (OR=0.35, 95% CI: 0.15–0.84, p=0.018), with a trend toward a stronger effect in high-SDI areas. In race-stratified models, statistically significant association was only present among Black patients (OR=0.34, 95% CI: 0.12–0.94, p=0.038); however, all races demonstrated a similar direction of effect between telehealth use and decreased odds of later Columbia stage. Models stratified by distance traveled showed similar directionality, but without statistical significance across distance quartiles.

Conclusion: Telehealth use prior to or on date of diagnosis was significantly associated with earlier Columbia stage, suggesting earlier ATTR-CM disease detection. This effect underscores the need to expand telehealth access to support timely diagnosis.