Life-threatening illness requiring emergency care accounts for 14.0% of emergency department (ED) visits in the US, and benefits from the earliest possible detection and care referral to improve patient outcomes and reduce hospital length of stay and care costs (1, 2). If patient understanding/self-perception underestimates actual acuity and risk indicated by symptoms and past medical history, patients may delay care seeking (3–5). Delayed care results in avoidable mortality and drives higher acuity care utilization that is more costly than might have been needed had the patient sought care earlier (3, 6).

Symptomate is a current generation digital virtual triage (VT) engine or “symptom checker” that leverages artificial intelligence (AI) to provide access to authoritative information services beyond physician office hours on a 24/7/365 basis from any device with internet connectivity. VT can avert long ED waits or travel, and helps when individuals are uncertain if symptoms warrant medical attention or what kind of care to seek, or if symptoms worsen. The VT interview asks questions about age, sex, symptoms, medical history, risk factors, and medications and, processing responses on a current basis, selects the next most relevant question via Bayesian probabilities, simulating the manner in which a human clinician processes information. After evaluating all patient data, the VT inference engine computes the probabilities of likely conditions using a statistical algorithm for advanced symptom assessment informed by an underlying medical knowledge base. The VT AI advises the patient-user of probable causes, illness severity, and recommended acuity level of medical care. VT is superior to internet browser search because patients are evaluated systematically to identify/convey a care acuity level using clinical AI algorithms validated by physicians. VT AI improves upon traditional clinical triage protocols or decision trees in its ability to dynamically calculate the probability of possible conditions and adjust the patient interview accordingly. However, VT results are not diagnostic and do not constitute medical consultation, providing information and guidance only. Users are advised to seek immediate medical attention when the VT engine determines that a threat to life exists.

Critical to maximizing the clinical and public health impact of VT AI is identifying functional areas where it can enhance existing diagnostic processes and capabilities. It is unknown whether AI-based VT can augment existing healthcare system capabilities for early identification, care acuity alignment, and rapid care referral of individuals whose self-perception of disease acuity/risk is inaccurate when serious morbidity is actually evolving. Patient delay in seeking urgent care across life-threatening diseases increases mortality (3, 7). When patient perception-understanding of symptoms/risk is decoupled from high actual risk of a severe clinical outcome, if identified reliably by VT in real-time, ED care engagement can be accelerated. VT may thus offer a new opportunity for early life-threatening disease detection, enabling improved, more rapid care acuity alignment and ED referral. VT could enhance existing healthcare system capabilities and efforts to reduce preventable disease sequelae and death. This study evaluates decoupling of actual care acuity need from patient care intent/risk self-perception as detected by a clinically validated VT engine available cost-free online. We examine data on patient perception-actual risk decoupling during severe symptom onset of five leading causes of U.S. hospital admission and death.

Delays in care seeking during medical emergencies negatively impact patient outcomes, and may result from patients failing to understand, dismissing or underestimating serious symptoms, and/or attempting to self-treat serious clinical problems at home (3). Table 6 summarizes causes and impact of care delay for the five conditions evaluated. Early detection and prompt, acuity appropriate treatment are crucial in improving outcomes of MI, which killed 108,610 Americans in 2018 (13). Almost 48% of VT patient-users with likely MI understood their symptoms required physician care but not immediate/urgent care, yet 28.1% planned to recover at home with no medical care (ED overtriage adjusted). This aligns with national mortality data. Reducing MI care delays focuses on patient education about symptoms warranting early care seeking (3, 18, 19), and can be integrated with VT.

In 2019, stroke accounted for 1 in 19 US deaths, the fifth leading cause of mortality (22, 33). Prehospital suspicion of stroke compressed time to computer tomography by 219 minutes and to stroke unit care by 556 minutes, reducing mortality (23, 34). However, 42.0% of patients experienced pre-hospital delays due to little knowledge of stroke symptoms (21). In the present study, 45.6% of patient-users with stroke symptoms intended to pursue non-emergency care, including 24.0% who planned to recover at home or take no action (ED overtriage adjusted). Reducing pre-hospital stroke care delay and acuity of care mismatch is a priority (21, 23). VT can potentially reduce delays in emergency stroke care.

In 2019, asthma caused 1,835,901 US ED visits, 169,330 hospital admissions, and 3,524 deaths (35–37). Many deaths and admissions were preventable and related to care delays (5, 7). In total, 45% of patients did not seek medical care during the final fatal asthma attack (25).

In 2021, 1.4 million US cases of pneumonia were diagnosed in EDs, 47,956 of which were fatal (13). Pneumonia was a concomitant cause of death in 148,498 deaths (13). Timely antibiotic treatment reduced adjusted 30-day hospital mortality by 16.0% (27).

Pulmonary embolism caused 8,809 US deaths in 2018 (13), with untreated mortality of 30.0% (30). In-hospital mortality was 1.6% for early versus 43.2% for delayed PE diagnosis (31). Treatment was delayed for 4.2 days due to patient procrastination (29), with 18–38% of patients symptomatic a week or longer before diagnosis (32). VT well integrated with healthcare system triage and intake can potentially reduce patient underestimation of symptom severity and delays in care seeking for these deadly respiratory illnesses.

Our findings that 53.5% of patients (ED overtriage adjusted) who reported symptoms of these five life-threatening conditions had no pre-triage intent to engage urgent care, and 33.5% had no intent to seek any medical care, aligns with national data. Users of VT may wish to assess their symptoms without engaging local healthcare for convenience and/or to save time and expense. Patients may seek reassurance that their symptoms are relatively benign. This sampling of 12,000 interviews from over three million total VT episodes demonstrates that in a significant percentage, possible existence of a severe underlying cause of symptoms should prompt the patient-user to seek professional medical attention sooner than they would have otherwise planned. The potential to reduce morbidity and mortality by more timely assessment of ambiguous/unrecognized signs and symptoms has significant public health implications. We suspect that use of AI-driven VT may become a valuable addition to under-resourced healthcare systems unable to assess all patients who seek care for uncertain symptoms but who may be at elevated risk for more serious disease.

With respect to limitations of the study, it is pertinent to acknowledge that the data collected may have been affected by certain inaccuracies. For instance, patient-users may have clicked through initial questions regarding their pre-VT care intention or conveyed random responses in order to get to the part of the encounter they were interested in, for example the VT evaluation of symptoms presented. While we have no evidence that this behavior occurred in substantial numbers of VT patient-users, the question warrants further research consideration and detection measures if a prevalent behavior.

In the effort to change patient care seeking behavior when confronted with potentially life threatening symptoms, interventions are needed that improve patient engagement, education, understanding of the clinical signs and symptoms of these acute conditions, and which are effective in activating patients to immediately seek emergency care. Given that many lives are avoidably lost, and the quality and extent of others are diminished, our current inability to effectively engage and educate patients to seek urgent care when confronted with life threatening symptoms is an area demanding far greater behavior change research, along with associated research funding. Indeed, one wonders what could be achieved in understanding and affecting patient care seeking behavior change were this research to be funded at the level of pharmaceutical development and marketing of a new therapeutic to treat patients whose severity of illness could have been lessened, if we were more capable of identifying and activating these patients to earlier care seeking and reduction of care delay.

Clearly, current approaches to achieving these behavioral and care seeking objectives have been largely inadequate. Public awareness campaigns addressing the importance of seeking prompt medical care in cases of acute, life-threatening cerebrovascular symptoms, for example, demonstrate a positive impact (39) but are often episodic rather than continuous, which limits their long-term impact and benefit. Reliable online medical resources exist which educate about the importance of early recognition and care seeking for serious cardiac symptoms as well, but provide general, non-personalized medical information, which can lessen the impact on individual behavior.

Subsequent research should systematically assess patient outcomes in order to fully evaluate the potential of VT to earlier detect severe evolving pathologies, such as those reported here, and effectively motivate and accelerate patient care seeking. Prospective validation in a real world clinical setting could track outcomes of patients whose self-perception and healthcare intent prior to VT is decoupled from actual acuity and urgent care need. Using objective clinical parameters and endpoints, this would assess the role and clinical value of AI-enabled VT within a care delivery and patient engagement ecosystem. If thus validated, VT may offer payers, health systems and providers a real-time vehicle for earlier detection and engagement of at-risk patients to enable better care acuity alignment and rapid ED referral/ambulance dispatch for life-threatening conditions.

The impact of advanced diagnostics and therapeutics is blunted if patients do not rapidly engage appropriate acuity care to receive their benefits. This study suggests that VT AI may help accelerate the moment of disease detection and appropriate acuity level care engagement. VT lets a user know their condition may be more serious than they perceive and they should seek ED care. Integrated within a digital front door, VT can potentially accelerate early detection, care acuity alignment and live engagement/intake to save lives, reduce morbidity, and better utilize healthcare resources by reducing care delays due to patient uncertainty and/or misunderstanding. Future research should validate that VT can influence patient care seeking behavior to enable accelerated ED care referral or ambulance dispatch. If validated, VT may become an integral component in an AI-enhanced clinical information ecosystem that expedites detection and delivery of appropriate urgent medical care.

Currently, when patient care intent is decoupled from actual clinical need by patient misunderstanding or indecision, earlier care detection and accelerated care engagement to reduce care delay is a complex challenge. As remote diagnostic monitoring and telemedical capabilities advance in coming years, so too will AI-based VT. Rapid development in generative AI and large language models will deliver improved user experience of VT AI. The use of natural language to enable patient-users to communicate in a more effective and nuanced way with VT AI will enable greater sensitivity, engendering trust in the results and greater impact on patient-user behavior. Exploiting these emerging potentialities will require investment and multisector scientific expertise converging private industry and public-governmental interests, assets, and capabilities.

The VT industry is not sufficiently resourced to drive the research needed to explore the potential beneficial impact and value of AI-based VT in early detection and acuity-aligned care referral. Furthermore, population databases of what will soon be hundreds of millions of VT episodes across the industry are too valuable a data and research resource to be applied exclusively for purely commercial interest. The VT industry should enable access to its anonymized aggregate data by the US National Institutes of Health and Centers for Disease Control and Prevention, international agencies, academic medical centers, and healthcare organizations to investigate and progress the full potential value of VT in the emerging 21st century health IT and AI ecosystem.

The raw data supporting the conclusions of this article will be made available by the authors upon reasonable request.

The studies were conducted in accordance with the local legislation and institutional requirements. The participants provided their written informed consent to participate in this study.

GAG: Conceptualization, Data curation, Formal analysis, Investigation, Methodology, Project administration, Validation, Visualization, Writing – original draft, Software, Supervision, Writing – review & editing. AK-K: Conceptualization, Data curation, Formal analysis, Methodology, Validation, Writing – review & editing. GLG: Data curation, Project administration, Writing – review & editing. JR-S: Investigation, Writing – review & editing. SG: Conceptualization, Formal analysis, Resources, Writing – original draft, Writing – review & editing. TP: Investigation, Project administration, Supervision, Writing – review & editing. KK: Data curation, Project administration, Writing – review & editing. NM: Writing – original draft. MP: Conceptualization, Writing – original draft. Writing – review & editing. JJ: Conceptualization, Writing – original draft, Writing – review & editing. IL: Writing – review & editing. PO: Project administration, Supervision, Writing – review & editing.