Specialist to non-specialist teleconsultations in chronic respiratory disease management: A systematic review

Background Chronic respiratory diseases (CRD), are common public health problems with high prevalence, disability and mortality rates worldwide. Further uneven distribution of the health workforce is a major barrier to the effective diagnosis and treatment of CRDs. Teleconsultation between a specialist and non-specialist could possibly bridge the gap in access to health care and decrease CRD burden in remote areas. This review investigates the evidence for the effective use of specialist to non-specialist teleconsultation in the management of CRDs in remote areas and identifies instances of good practice and knowledge gaps. Methods We searched for articles till November 2020, which focused on specialist to non-specialist teleconsultations for CRD diagnosis or management. Two independent reviewers conducted the title and abstract screening and extracted data from the selected papers and the quality was assessed by Joanna Briggs Institute’s (JBI) tool. A descriptive and narrative approach was used due to the heterogeneous nature of the selected studies. Results We found 1715, articles that met the initial search criteria, but after excluding duplicates and non-eligible articles, we included 10 research articles of moderate quality. These articles were from nine different studies, all of which, except one, were conducted in high-income countries. The studies reported results in terms of impact on the patients, and the health care providers including primary care physicians (PCP) and specialists. The teleconsulting systems used in all the selected papers primarily used audio modes in addition to other modes like the audio-video medium. The included studies reported primarily non-clinical outcomes including effectiveness, feasibility, acceptability and usability of the teleconsultation systems and only three described the clinical outcomes. The teleconsultation was predominantly conducted in the PCP’s office with the specialist located remotely. Conclusions We found relatively few, papers which explored specialist to non-specialist teleconsultation in management of CRDs, and no controlled trials. Two of the included papers described systems, which were used for other diseases in addition to the CRD. The available literature although not generalisable, encourages the use of specialist to non-specialist teleconsultation for diagnosis and management of CRDs.

The distribution of the health workforce across the globe is uneven and is often disproportionately lower in low and middle-income countries (LMICs) which are the areas often with the highest disease burden [1]. The World Health Organization (WHO)-Global Health Observatory reports that over 40% of member countries of WHO, all LMICs, have less than one physician per 1000 population [1]. The African Region suffers more than 24% of the global burden of all diseases but has access to only 3% of health workers and less than 1% of the world's financial resources [1]. The unbalanced distribution of health care personnel by specialities adds to these disparities [2]. In India, while 69% of Indian population resides in rural areas and they are served by 22% of all health care providers compared with the 31% urban citizens who have access to 78% of trained health care professionals [3,4]. Poor access to transport and inadequate transport infrastructure in rural areas further aggravates the scarcity of health care workforce leaving a large proportion of the rural population without easy access to trained health care providers.
Information technology can facilitate access to specialist services, by overcoming the distance barrier by enabling specialist doctors to provide remote consultations to patients and provide support to general physicians and specialised local health workers [5,6]. Additionally, remote consultations have also provided opportunities for continued access to health care when maintaining social distancing during the global COVID-19 pandemic [7]. Telehealth care is thus one possible means of addressing the challenges related to uneven access to health care in India and globally [8].
Telehealth care is variously referred to as telemedicine, telehealth, telecare, telemonitoring, tele(discipline), teleconsultation and also eHealth in assorted contexts including mobile application based care, self-management with the help of remote monitors, doctor-to-patient remote consultation and also doctor-to-doctor consultation [9]. COCIR, the European Trade Association, representing the medical imaging, radiotherapy, health ICT and electromedical industries suggests a simpler definition that: "Telemedicine includes all areas where medical or social data is being sent/exchanged between at least two remote locations, including both Caregiver-Patient/Citizen as well as Doctor to Doctor communication" [5]. This definition is most applicable where telemedicine seems to have widened its scope to a variety of health information exchange for managing health and well-being of the population. For this systematic review, we will refer to this as 'Teleconsultation'.
Chronic respiratory diseases (CRD) especially asthma & Chronic Obstructive Pulmonary Disease (COPD) are common public health problems with high prevalence, disability and mortality rates worldwide [10][11][12][13]. Asthma is the 14 th most important disorder in the world in terms of the disease burden [14], and COPD is the third leading cause of death, worldwide [15]. Diagnosis of these chronic respiratory diseases is based on detailed patient history and clinical assessment, aided by specialised tests such as spirometry and peak expiratory flow readings. However, interpreting the results of such tests require specialised training [16]. Specialists are not always available in rural regions worldwide. A study conducted in the US reported that less than one-third of the rural population, but nearly 98% of the urban American population had access to a pulmonologist within a 10-mile radius [17]. The situation in low-and middle-income countries (LMICs) like India is comparatively worse. The Association of Chest Physicians of India lists 2413 chest physicians in a country of 1.3 billion people, more than 95% of these are registered at in large urban areas [18] as compared to American Thoracic Society comprising of more than 16 000 registered members including physicians, researchers, advanced practice nurses, respiratory therapists which serves nearly 331 million population [19]. The rural areas in LMICs are primarily served by primary care physicians (PCP) or allied health staff including Auxiliary Nurse Midwives (ANMs) nurses or pharmacists for delivery of primary health care [20]. Lack of access to pulmonologists and other specialists required for the diagnosis and management of the CRDs may be one of the factors contributing to the misclassification or delayed diagnosis of CRDs and inappropriate disease management. Use of teleconsultation to remotely support the PCPs by engaging specialists could help in scaling up CRD diagnosis and treatment.
The objective of this systematic review was to explore the evidence for the effective use of specialist to non-specialist teleconsultation in the management of CRDs in adults in remote areas and to document best practices and challenges; and identify, knowledge gaps and provide recommendations for future research.

Database
We used Embase, Medline (through Ovid), PubMed, and CAB Global Health to run our search terms. RP handsearched citation lists to identify potentially relevant papers within retrieved papers and review articles.

Search duration
We searched for papers up to November 2019 and later the search was repeated in November 2020. We did not restrict the start date, although first publication in the search appeared in 1975.

Inclusion and exclusion criteria
We considered all types of research methodologies including interventions as well as observational studies. All types of teleconsultation between specialists and non-specialists for CRD diagnosis or management, including but not limited to email, videoconference, telephone etc. were included. We excluded articles, which were focused on home-based care, mobile health, doctor to patient consultations, molecular outcomes, pulmonary rehabilitation, telephone surveys, post-hospitalisation follow-ups, telemonitoring and tele-training. We also excluded reviews, systematic reviews and conference abstracts and the search was not restricted to any particular language.

Data extraction and analysis
The title and abstract screening followed by data extraction from the selected papers was independently conducted by two reviewers (RP and RS). The search results from all databases were imported into Mendeley (1.19.5) [22] and the duplicates were removed. The titles and abstracts were screened for all the papers. We selected studies mainly on two criteria. The first criteria is the disease condition, including at least one chronic respiratory illness, and the second criteria is consultation type, where a specialist provided consultation to non-specialists or a PCP, to either diagnose or treat the chronic respiratory disease.
Data extraction into Microsoft excel was developed based on the STROBE [23], NICE [24], CASP [25] and CONSORT [26] guidelines and included fields on the type and aim of the study, population description, disease condition, type of consultation, type of outcome and facility. The discrepancies were resolved by discussions between RP and RS. The narrative data was extracted using summary tables independently by two authors (RP and RS) which were later combined by one reviewer (RP) into one sheet and all authors reviewed this sheet regularly. Mendeley (1.19.5) [22] was used to manage references and MS-Excel (Microsoft Inc, Seattle, WA, USA) was used for data management. The quality assessment of the papers was carried out using the Joanna Briggs Institute's (JBI) tool for critical appraisal [27] by two reviewers (RP and RS). The discrepancies were resolved by discussion.
The study designs of the selected papers were heterogeneous thus a narrative approach to data synthesis was used rather than a meta-analysis.

RESULTS
The identified papers, the screening process, and the final number of studies included are detailed in the PRIS-MA flowchart (Figure 1). In summary, we found 1715 papers in the above-mentioned databases, of which 464 were duplicates, which were excluded, leaving 1251 papers. We screened the abstracts of all these 1251 papers of which 77 were selected for full-text screening based on the inclusion criteria. We further selected only published papers hence we did not include 21 meeting abstracts/conference papers. We found 10 relevant papers which included all three parameters of (i) teleconsultation, (ii) Specialist to non-specialist consultation (iii) CRDs.

Study population
The study populations in the selected studies primarily included two groups namely the patients and the health care provider including PCPs and specialists. Some studies also conducted secondary data analysis thus indirectly including patients as study participants [28,29]. The demographic characteristics of the study population were not described in any of the papers. The available details including a description of the recruitment methods in the included studies are described in Table 1.    PCPs who were willing to conduct telespirometry. Pulmonology units identified by a steering committee. Subjects on whom the PCP conducts telespirometry. The paper mentions that the details are described in another publication describing this study [31] however, no more details are mentioned about the recruitment methods Bernocchi et al [33] Patients: Patients who were screened for eligibility before hospital discharge and who consented.
Patients at the PCP clinic. Before discharge from the hospital all patients were given instruction on their respective disease conditions (CHF or COPD

Consultation type and facilities used
We included studies where a specialist communicated with a non-specialist by teleconsultation for either diagnosis or management of the patient's condition. In one study, consultations were conducted in real-time [30], the others were stored and forwarded consultations, which meant the specialists were sent the patient details and reports by the non-specialists and the specialists provided their opinion to the non-specialists within a stipulated time frame.
The case studies conducted in Japan described a setup which comprised of equipment at three locations which included the home of two patients with chronic respiratory failure, the hospital of the attending PCP, and the hospital of the pulmonary specialist [30]. No other study reported home-based specialist to non-specialist teleconsultation.
The primary care centres or PCP's offices were used as the site of the teleconsultation in six studies which were reported in seven papers [28,29,[31][32][33][34][35] where the consulting specialist was located at a remote location. These studies could be categorised as the hub and spoke where multiple PCPs were provided with an opinion by specialists for either diagnosis or management of CRDs. In one study reported from the USA, the hub was located at Milwaukee Veteran Affairs Medical Centre (VAMC) pulmonary telemedicine clinic which was located away from the spoke centre at Iron Mountain VAMC [28]. Five other studies had similar approach where the teleconsultation was conducted at the PCP's office and the specialist provided an opinion for the diagnosis or management remotely [29,31,32,34,35]. The teleconsultation was conducted between specialists at local hospitals and specialists at a tertiary care hospital in two studies [36,37] ( Table 2). Asthma and COPD Training to PCPs by pulmonologists followed by PCPs performing spirometry in their clinic which was checked for quality by the gen at the central office providing teleconsultation and further offered an interpretation of the results which was faxed to the PCPs' office. Bonavia et al [32] 2009 Italy Observational study persistent respiratory symptoms, or a previous diagnosis of asthma or COPD Training to PCPs by pulmonologists followed by PCPs performing spirometry in their clinic which was checked for quality by the specialist at the central office and further offered an interpretation of the results which was faxed to the PCPs' office. Bernocchi et al [33] 2012 Italy Description and assessment of an ongoing project

Details of the systems used for teleconsultations
The specific teleconsultation systems used in all the selected papers varied; broadly they primarily used audio modes but some use a mixture of audio-video. Three papers from two studies focused on diagnosis using telespirometry.
Koizumi et al. shared clinical information, using a remote biological information transmission device which was installed at the patient's home. Equipment to measure arterial blood oxygen saturation and blood pressure was set up on the patient's finger along with three electrodes for Electrocardiogram. The remote consultation management device was set up at the attending PCP's hospital. Besides, another device for consultation management and monitoring was set up at Shinshu University Hospital, where the pulmonary specialist was located [30].
Another study described a hub-and-spoke model where the nurse or respiratory therapist (RT) at the spoke site recorded the clinical history and conducted a focused pulmonary physical examination. Medical consultations at the hub site were conducted via the live, two-way audio and video conferencing system. The physician at the hub site viewed chart notes and images of Electrocardiogram and radiographs and further prescribed diagnostics, medicines and suggested if the patient needed face to face consultations [28].
The Italian Alliance study published two papers in 2009 focusing on telespirometry for diagnosis of CRDs. One pulmonary specialist provided education and training on spirometry and diagnosis of obstructive airway diseases, to a group of PCPs in a six-hour education session. Each PCP was equipped with a simple, portable pneumotachograph (Spirotel, MIR, Roma, Italy) to measure the main indices derived from a maximal forced expiratory manoeuvre, the reports of which were transmitted to a central office. The operator at central office established a real-time communication and commented on the quality of the spirometry traces, invited the PCP to perform additional expiratory manoeuvres in the same subjects, and offered an interpretation of the results of the single patient. Then, the report was sent by fax to the PCP's office [31,32].
The descriptive paper on the TELEMACO project narrates that a service centre provided support to PCPs during daily in-office or home visits and for pulmonology consultations, PCPs contacted the service centre using a real-time telephone only and no special service was used [33].
An intervention study focused on telepulmonology consultations used a hypertext transfer protocol secured, web-based teleconsultation system for communication between PCP and pulmonary specialist. PCPs accessed a secured web-based teleconsultation system (KSYOS Telemedical Centre, Amstelveen, The Netherlands) where they completed the patient personal data, added up to four PDF's of the spirometry results and optionally added additional relevant clinical information. This information was sent to the local pulmonary specialist who had to answer within two working days [34].
Another study which focused on providing asthma and COPD services used an Electronic diagnostic support (EDS) system. After referral of a patient by the PCP to the asthma COPD services, a trained lung function technician conducted spirometry and along with the patient completed the patient information and clinical history in the EDS. This information was accessed by a Pulmonary specialist for assessment within five days which was then reported to the PCP who further decided on disease management [35].
A similar store and forward system was used by Fadaizadeh et al. for patients who have undergone thoracic surgery with multiple organ failure. The receiving PCP provided all necessary documents (the patient's history, tests, ECG, radiology documents) and transfer to the specialist via store and forward, and then discussed the case online via videoconference. Fibre optic communication; and web conference software was used for a simultaneous audio-visual connection. Tele-examination devices and equipment were provided including a camera for examining the ear, eye and also digital stethoscope for heart and lung examination. A communication network for specialised consultations was established among seven specialised hospitals [36].
The study which described the use of High-Resolution Computed Tomography (HRCT) scans for identifying Usual Interstitial Pneumonia (UIP)-pattern in patients with suspected Idiopathic Pulmonary Fibrosis with clinicians performing the Chest HRCT scans locally at the referring hospitals. The HRCT scans were sent for a centralised expert consensus reading by a radiologist and a pulmonary specialist. After registration, a pulmonary specialist in partner hospitals received a personalised upload link valid for a single patient who had consented and for short period. All data for the patient were uploaded to the central expert reading site. A radiologist and pulmonary specialist together generated report for the patients and the reports were sent back by encrypted email to the referring PCP in the local hospital [37].
A retrospectively described study used eConsult services, where the PCPs at the point of referral, had the option to submit an eConsult request, using a structured template, if they believed the specialist could address the clinical question without an in-person evaluation. Specific structured referral templates for the most common clinical problems referred to each speciality, which incorporated relevant laboratory data from the EHR, allowed PCPs to identify if relevant imaging data were available, and asked the PCP to provide a recent assessment and a specific clinical question [29].

Study outcomes
The included studies focused primarily on non-clinical outcomes including effectiveness, feasibility, acceptability and usability of the teleconsultation systems. Three of the 10 studies described the clinical outcomes more clearly [28,35,37] one study which described observations of patients' assessment as clinical outcomes [30] did not provide sufficient details to assess their methods. The description of the study methods used to collect the data and respective study outcomes are listed in Table 3. We further describe the common conclusions from all the 10 selected papers.

Effectiveness
Two papers described the effectiveness of the existing system. Koizumi et al. describes that the system was effective for establishment of appropriate treatment, provided the cooperation between the pulmonary specialist and attending PCP was established and further suggests that a similar system could be considered useful and promising for further use [30]. Fadaizadeh et al. studied teleconsultation between physicians and nurses at the thoracic surgery hospital and consulting physicians, in thoracic surgery patients in intensive care unit and concluded that teleconsultation improved decision-making in thoracic surgery ICU patients through time saving and accelerating off-site consultations [36] ( Table 4).

Reliability
The use of specialist to non-specialist teleconsultation was considered reliable in terms of technical feasibility [28,29,33,35,37]. However, concerns were raised in one study that the pulmonary specialist relied primarily on medical history, medical data from tests including radiology, and a limited physical exam performed by a trained nurse or respiratory therapist to arrive at clinical diagnosis [28].

Improved patient access
The systems utilised in multiple studies were reported as improving health care access to patients. Referred patients were able to receive medical subspecialty care closer to home, obviating the need for long-distance travel to receive an in-person medical consultation [28,33,35] ( Table 3).

Use of teleconsultation for diagnosis
Three papers primarily focused on disease diagnosis [31,32,35]. The Italian Alliance study shows that telespirometry in the primary care setting could reliably demonstrate spirometric abnormalities and detect airflow limitation even in asymptomatic patients who are at risk of suffering from CRDs [31,32]. Another study also supported the finding that teleconsultation was feasible, effective and efficient in supporting PCPs to diagnose and manage asthma, COPD and overlap syndrome patients [35] ( Table 3).

Acceptability
Specialist to non-specialist teleconsultation is highly dependent on the collaboration between health care providers and how acceptable they found the systems. Fadaizadeh et al. reported high physician satisfaction and acceptance of teleconsultation by the specialists [36]. Further, telespirometry was well accepted and could be easily performed by a large number of PCPs [31,32]. The rate of acceptable spirometric tests can be improved if the tests are performed under the supervision of trained technicians rather than by the PCPs [28,33,35]. One study showed that the service was perceived to stimulate cooperation between primary and secondary care, and deliver support to patients locally which is important in rural areas [35]. Telepulmonology, by improving the collaboration between PCP and pulmonary specialist, may prevent unnecessary face-to-face referrals thus saving time, and aiding in preventing under and misdiagnosis of COPD [34].

Disease conditions
COPD was addressed in two studies [30,34], both asthma and COPD in three studies [31,32,35], one study focused on general respiratory conditions [28] and two studies on multiple specialities, pulmonology being one of them [29,33]. Fadaizadeh et al. specifically investigated patients who had undergone thoracic surgery Electrocardiogram and heartrate and oxygen saturation which was recorded in the system and partial pressure of expiratory carbon dioxide was reported to the physician verbally.
One year for patient 1 and for patient 2 not mentioned. Weekly communication within all three parties No analysis is presented in the paper 1. Depression; 2. Other health issues; 3. Respiratory symptoms were observed and discussed; however, the paper does not mention clear clinical outcomes neither the methods which were used for measuring these clinical outcomes Effectiveness of system connecting multiterminal. The trial program resulted in the same information being exchanged remotely using the multi-station teleconsultation system that would be exchanged in a direct, face to-face encounter The clinician's observations are described in the results section. No specific method is mentioned to document the observations. The paper does not clearly mention the aims of the publication. The result describes that the system is effective yet the methods do not describe measuring the effectiveness although the study of two cases proves the feasibility of the intervention.
Raza et al [28] Retrospective data analysis. The authors extracted data from computerized patient record system, paper chart, physician logbooks of teleconsultation visits, patients written comments after completion of teleconsultations. The data analysed is extracted from the system included a range of sub-specialities however this paper describes data from pulmonary patients only. The analysis for the qualitative data are not described. Data from single teleconsultation spoke centre is described which cannot necessarily be representative of the com- Telepulmonology can contribute to more efficiency and a higher quality of care for COPD patients. The clinical follow up of the patients is not done, neither any data mentions if the patient visited the pulmonologists after the suggested referral.
The pulmonologists are not asked about the services/ the data are not presented in the paper. The pulmonologists responded after 18 h average; however, the paper does not mention how the patients were informed about the diagnosis/ treatment suggested.

Clinical outcomes
Other outcomes

Study limitations and critique
Metting et al [35] 1. Feasibility: the proportion of PCPs in the target area who used the AC service, the proportion of patients with asthma or COPD who were assessed by the service, the quality of the spirometry and the number of patients that could be diagnosed, and the variation in diagnostic pattern between the different pulmonologists by using Follow-up visits. Patients for whom medication change was advised by the pulmonologist were automatically scheduled for an additional follow-up assessment after 3 mo 2007 to 2012 (5 y) Nonparametric paired tests were used to compare baseline data with follow-up data. Paired The paper describes the tele-ICU for thoracic surgery patients however, the consultation provided was mostly for other problems and only two consultations of thoracic surgery are mentioned in the results. Moreover, the number of consulting physician/s is not mentioned in the paper Weikert et al [37] Authors evaluated basic patient characteristics (age and sex) as well as the geographic distribution of referring hospitals. Furthermore, authors analysed technical aspects like slice thickness, tube current (mAs) and peak kilovoltage, determined whether the slice thickness of transmitted CTs complied with the recommendations defined by the Fleischner Society and in the ATS/ERS/JRS/ ALAT-guideline. A questionnaire based online survey was conducted to assess satisfaction with and impact of the program and the structured reports that were generated within the context of the teleradiology program.
Jan 2014 to May 2019 (5 y) Descriptive statistical analysis Satisfaction with the centralized IPF expert teleradiology program was 8.4 (out of 10). Their impact on the clinical management of the patients was rated 9.0/10. The utility of the teleradiology program regarding the gaining of own expertise in IPF was assessed as 9.3/10. All referring physicians (100%) stated that they would recommend the centralized IPF teleradiology program to their colleagues The HRCT referral although was intended from 12 countries, half of those did not contribute to even 10% of the total number of scans. The survey was taken only by one third of the total participating physicians hence the satisfaction results couldn't be generalized.
Wrenn et al [29] Authors categorized the question asked during teleconsultation as "diagnosis," "treatment," and/or "monitoring." They further reviewed the medical record to determine the percentage of specialist recommendations PCPs implemented, and the proportion of patients with a specialist visit in the same specialty as the teleconsultation emergency department visit, or hospital admission during the follow-up August 2012 and January 2013 (6 mo)

Descriptive statistics
No clinical outcomes 1. PCPs asked questions related to diagnosis in 71% of cases, treatment in 46% of cases, and monitoring in 21% of cases; 2. CPs ordered 79% of all recommended laboratory tests, 86% of recommended imaging tests and procedures, 65% of recommended new medications, and 73% of recommended medication changes. In the six months after the teleconsultation, 14% of patients had a specialist visit within the UCSF system in the same specialty as the teleconsultation The patient visit to specialists were recorded if the patient visited the same hospital, however, there is a possibility that the patients could access another health care facility. The results are analysed from the data collected from one centre hence the results may not be generalizable.  Two patients with chronic respiratory failure, attending PCP, and one pulmonary specialist To create and test a multi-station teleconsultation support system, three remote locations were connected: the homes of two patients with chronic respiratory failure, the hospital of the attending PCP and a pulmonologist in another hospital The effectiveness of a system connecting multiple terminals for teleconsultation. (Notes: although the methods to measure the effectiveness is not described). The feasibility of use is established Two patients with chronic respiratory failure, the hospital of the attending PCP, and the hospital of the pulmonary specialist.
Raza et al [28] Six pulmonary specialist at the Milwaukee site and the patient and ancillary provider (nurse or respiratory technologist -RT) at the Iron Mountain. 314 patients The goals of the study were (1) to evaluate the use and effect of teleconsultation technology to provide consultative outpatient care for a broad range of pulmonary conditions; and (2) To evaluate the use of a teleconsultation program in terms of (a) access to care (including reduction in both travel for patients and waiting time for appointments), (b) clinical decision making (medical interview and physical exam, medical work-up required, and outcome of teleconsultation), and (c) patient disposition (need for follow-up care and need for in-person evaluation) The aims of the project were 3-fold: (1) to implement and use continuity-of-care services (2) to design a network in the territory for sharing continuity-of-care programs for the management of chronic diseases (3) to allow the health authority to collect data to establish sustainable pricing at the regional health level for implementing TM Thijssing et al [34] 158 PCPs and 32 pulmonologists To assess the effect of telepulmonology on quality and efficiency of care Effect of telepulmonology on quality and efficiency of care PCPs office and pulmonary specialist's office Metting et al [35] 11401 patients suspected to have obstructive airway disease (OAD) 360 PCPs from north Netherland, 10 pulmonologists To improve the management of asthma and COPD patients in primary care using an internet-based service Feasibility, effectiveness and efficiency in supporting PCPs to diagnose and manage asthma, COPD and overlap syndrome patients.
PCP's office, Laboratory facility for conducting spirometry and pulmonary specialist's office. Communication over internet Fadaizadeh et al [36] 1. 58 Thoracic surgery patients; 2. consulting physician located in a remote hospital To assess the advantage of teleICU by accelerating consultations and bringing physicians' satisfaction from teleconsultation outcomes 1. Comparison of the pace of teleconsultation and regular(bedside) consultation of ICU patients admitted during the year before starting tele-ICU; 2. the physicians' satisfaction from teleconsultation Tertiary pulmonology/ thoracic surgery hospital (location of specialist is not mentioned) Weikert et al [37] Databased analysis no study population. Data from 239 hospitals located in 46 cities in 12 countries To support referring centres to interpret HRCT with respect to UIP in patient with suspected Idiopathic Pulmonary Fibrosis (IPF) Feasibility of cross-border teleradiology for the provision of state-of-the-art reporting Referral hospitals (location of specialist is not mentioned) Wrenn et al [29] 86 Primary care providers (PCP) from eight adult primary care sites at the University of California, San Francisco (UCSF), USA, 195 patients To analyse how the teleconsultation program affects clinical management of patients in primary care Percentage of specialist recommendations PCPs implemented, and the proportion of patients with a specialist visit in the same specialty as the teleconsultation, emergency department visit, or hospital admission during the subsequent six months PCPs office (location of specialist is not mentioned) with multiple organ failure [36] and Weikert et al. included patients with presence of Usual Interstitial Pneumonia (UIP)-pattern in patients with suspected Idiopathic pulmonary fibrosis (IPF) [37].

Study designs
The 10 papers included in this review are summarised in Table 2 and the aims and outcome measures in the included studies are described in Table 4. There were no randomised controlled trials or controlled before-and-after studies. Four studies, which yielded five papers, were cross-sectional studies which described numbers of patients and health systems where teleconsultations were implemented [28,31,32,34,36]. Two of these five publications were about ongoing systems described retrospectively [28,34]. Three papers described the ongoing systems [29,33,37], two of which used descriptive statistics to report the outcomes quantitatively [29,37] and the remaining one was a narrative technical description of the teleconsultation system [33]. Only one study, which described three case reports, did not include any quantitative analysis [30] and one study described data at baseline and assessed the patients' clinical outcomes longitudinally after the intervention [35].

Country of the studies
All but one of the included studies were conducted in high-income countries. Five papers referred to four studies conducted in Europe [31][32][33][34][35], two in the US [28,29] and one each in Japan [30] and Iran [36]. One study was conducted in a network collaboration of 12 hospitals in Central Eastern Europe and Asia [37] ( Table 2).

Quality assessment and limitations of the included studies
The quality assessment of the studies was done using JBI tools [27] ( Table 5, Table 6 and Table 7). All papers were rated as moderate or low quality. Papers were assessed based on study types. Three papers were assessed as text or opinion papers ( Table 5), half of the selected papers were analytical cross-sectional studies ( Table  6), one a study of diagnostic accuracy and one a case study ( Table 7) and were assessed using respective parameters. All the selected studies have certain limitations ( Table 3). The opinion papers [29,33,37] did not logically defend incongruence with the literature/sources, whereas the confounding factors were either not considered or mentioned in the cross-sectional analytical studies [28,31,32,[34][35][36]. The one case study [30] reported is a low-quality paper.

Disclaimer:
The views expressed in the submitted article are those of the authors' own and not an official position of the institution or funder.

CONCLUSIONS
We found no controlled trials and relatively few papers mainly of a moderate or low quality which explored specialist to non-specialist teleconsultation in the management of CRDs. This is in contrast to other specialities where comparatively more papers are available describing doctor to nurse or specialist to non-specialist consultation including dermatology [38], psychiatry [39,40] and radiology [41].
Of the included papers a few described systems which did not focus on any one particular disease and lung diseases were just one of the conditions which were managed using these teleconsultation systems. Although some studies indicated that such specialist to non-specialist consultation may have resulted in more local treatment and a lower proportion of referred cases to specialists. The absence of baseline data in some means it is not clear to what extent it may have increased appropriate referrals for patients who previously did not have easy access to diagnosis.
Teleconsultation in the PCPs office with the remotely situated consultant in the hub and spoke model was the most preferred way of conducting specialists to non-specialist consultation and the audio mode was primarily used for consultation. This concludes to be one of the most logistically feasible models for PCPs and specialists and also fulfils the patients' requirements. Very few studies were conducted in the LMICs and most were reported from European counties. It is possible that specialist to non-specialist consultations for CRD diagnosis and management using teleconsultation are taking place but are not being reported in academic literature. The studies we selected were relatively recent and published during the last decade.
While the available literature does not indicate any generalizability, it shows some encouragement that specialist to non-specialist teleconsultation may facilitate diagnosis and management of CRDs to the benefit of patients. However, CRD diagnosis using specialist to non-specialist teleconsultation was more pragmatic and manageable as against the CRD management.
The use of teleconsultation may potentially help patients for CRD diagnosis and management, where face-toface consultations are not available [42]. Studies have proven to have a positive impact on the quality of life of the patients suffering from CRDs and acceptance by the health care provider [43]. Further, high-quality research to demonstrate the efficacy of the use of specialist to non-specialist consultation for managing CRDs is required to be conducted in controlled settings. A strategy to build evidence to deploy specialist to non-specialist teleconsultation to manage CRDs will aid further research [44,45]. More high-quality controlled studies are required to confirm these suggestions. Funding: RP is supported by PhD studentships from the NIHR Global Health Research Unit on Respiratory Health (RE-SPIRE). RESPIRE is funded by the National Institute of Health Research using Official Development Assistance (ODA) funding. This research was commissioned by the UK National Institute for Health Research (NIHR) Global Health Research Unit on Respiratory Health (RESPIRE), using UK Aid from the UK Government. The views expressed are those of the author(s) and not necessarily those of the NHS, the NIHR or the Department of Health and Social Care. Neither the funder nor the sponsor (University of Edinburgh) contributed to protocol development.
Authorship contributions: RP conceptualised the review with support from BM, KF and SJ. RP and RS conducted the search and data extraction and RP wrote the first draft of this manuscript. All authors gave critical comments and contributed to the manuscript.