Digital and online symptom checkers and assessment services for urgent care to inform a new digital platform: a systematic review
Authors: Chambers Duncan , Cantrell Anna , Johnson Maxine , Preston Louise , Baxter Susan K , Booth Andrew , Turner Janette 
Published: August 2019

Background
Digital and online symptom checkers and assessment services are used by patients seeking guidance about health problems. NHS England is planning to introduce a digital platform (NHS111 Online) to operate alongside the NHS111 urgent-care telephone service. This review focuses on digital and online symptom checkers for urgent health problems.

Objectives
This systematic review was commissioned to provide NHS England with an independent review of previous research in this area to inform strategic decision-making and service design.

Data sources
Focused searches of seven bibliographic databases were performed and supplemented by phrase searching for names of symptom checker systems and citation searches of key included studies. The bibliographic databases searched were MEDLINE, EMBASE, The Cochrane Library, CINAHL (Cumulative Index to Nursing and Allied Health Literature), HMIC (Health Management Information Consortium), Web of Science and the Association of Computing Machinery (ACM) Digital Library, from inception up to April 2018.

Review methods
Brief inclusion criteria were (1) population – general population seeking information online or digitally to address an urgent health problem; (2) intervention – any online or digital service designed to assess symptoms, provide health advice and direct patients to appropriate services; and (3) comparator – telephone or face-to-face assessment, comparative performance in tests or simulations (studies with no comparator were included if they reported relevant outcomes). Outcomes of interest included safety, clinical effectiveness, costs or cost-effectiveness, diagnostic and triage accuracy, use of and contacts with health services, compliance with advice received, patient/carer satisfaction, and equity and inclusion. Inclusion was not restricted by study design. Screening studies for inclusion, data extraction and quality assessment were carried out by one reviewer with a sample checked for accuracy and consistency. Final decisions on study inclusion were taken by consensus of the review team. A narrative synthesis of the included studies was performed and structured around the predefined research questions and key outcomes. The overall strength of evidence for each outcome was classified as ‘stronger’, ‘weaker’, ‘conflicting’ or ‘insufficient’, based on study numbers and design.

Results
In total, 29 publications describing 27 studies were included. Studies were diverse in their design and methodology. The overall strength of the evidence was weak because it was largely based on observational studies and with a substantial component of non-peer-reviewed grey literature. There was little evidence to suggest that symptom checkers are unsafe, but studies evaluating their safety were generally short term and small scale. Diagnostic accuracy was highly variable between different systems but was generally low. Algorithm-based triage tended to be more risk averse than that of health professionals. Inconsistent evidence was found on effects on service use. There was very limited evidence on patients’ reactions to online triage advice. The studies showed that younger and more highly educated people are more likely to use these services. Study participants generally expressed high levels of satisfaction with digital and online triage services, albeit in uncontrolled studies.

Limitations
Findings from symptom checker systems for specific conditions may not be applicable to more general systems and vice versa. Studies of symptom checkers as part of electronic consultation systems in general practice were also included, which is a slightly different setting from a general ‘digital 111’ service. Most studies were screened by one reviewer.

Conclusions
Major uncertainties surround the probable impact of digital 111 services on most outcomes. It will be important to monitor and evaluate the services using all available data sources and by commissioning high-quality research.

Future work
Priorities for research include comparisons of different systems, rigorous economic evaluations and investigations of patient pathways.

Study registration
The study is registered as PROSPERO CRD42018093564.

Funding
The National Institute for Health Research Health Services and Delivery Research programme.