Table 2.
Details of the 26 contingent valuation studies included in the final sample.
| Study | Country (year of study) | Population and sample size (N) | Age (years) | Women (%) | eHealth details | Measurement of WTPa (format, ex ante or ex post, and zeros) | WTP (PPPb, and 2021 US dollar value) | ||||||||
| Contingent valuation studies that reported WTP as a 1-time payment (n=17) | |||||||||||||||
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Adedokun et al [50] | Nigeria (2011) | Patients at a family medicine unit (389) | Mean 42.1 | 54 | An SMS text messaging–based appointment scheduling service: patients sent an SMS text message to book a clinic appointment and received a confirmation SMS text message and another SMS text message reminding them of the appointment | Open-ended; ex ante; all zeros excluded | Mean 2.81 (SD 3.88), range 0.06-38.26 | |||||||
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Belkora et al [51] | United States (2007-2010) | Patients with breast cancer (34) | Mean 59 | 100 | A telephone consultation planning service: before a clinical visit, a community health worker called the patient to check if they had any medical questions and then sent the list of questions to the patient’s physician | Double-bounded dichotomous choice; ex post; all zeros included | Mean 191.84 (SD 242.91) | |||||||
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Bergmo and Wangberg (1) [52] | Norway (2003) | Patients at a primary clinic (52) | Mean 38 | 70 | An internet-based messaging system that enabled patients to communicate with their health care providers by sending messages using a web browser | Open-ended; ex ante; protest zeros excluded | Mean 10.94 (95% CI 8.91-13.17); median 10.14 (IQR 5.07-20.26) | |||||||
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Bergmo and Wangberg (2) [52] | Norway (2003) | Patients at a primary clinic (38) | Mean 37 | 61 | Same as Bergmo and Wangberg (1) [52] | Open-ended; ex post; protest zeros excluded | Mean 7.30 (95% CI 5.47-8.91); median 7.09 (IQR 2.03-10.14) | |||||||
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Brandling-Bennet et al [53] | Cambodia (2003) | Patients at a clinic (49) | Mean 39 | 61 | A telemedicine service: local nurses recorded the medical history and conducted physical examinations of patients and sent this information to physicians at a remote place via email; the physicians would then reply with the treatment or referral decisions; the local nurses would execute the recommendations | Not reported; ex post; all zeros excluded | Median 0.90, range 0-72.53 | |||||||
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Fawsitt et al (1) [54] | Ireland (2015) | Women in antenatal clinics (20) | Mean and median not reported | 100 | A mobile app that provided information about cesarean section and surgical site infections: users recorded symptoms, temperature, heart rate, and pain level based on which the app would provide health advice (eg, check body temperature or contact a general practitioner) | Open-ended; ex ante; all zeros included | Mean 30.96 (SD 58.28); median 13.98 | |||||||
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Fawsitt et al (2) [54] | Ireland (2015) | Women in antenatal clinics (116) | Mean and median not reported | 100 | A mobile app that provided information about cesarean section and surgical site infections: users recorded symptoms, temperature, heart rate, and pain level, which would be checked daily by a midwife in the maternity hospital who would provide health advice to the user | Open-ended; ex ante; all zeros included | Mean 36.38 (SD 51.46); median 13.98 | |||||||
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Fawsitt et al (3) [54] | Ireland (2015) | Women in antenatal clinics (44) | Mean and median not reported | 100 | A telephone call–based helpline service: users called a midwife in the maternity hospital, who would provide health advice and instructions | Open-ended; ex ante; all zeros included | Mean 32.76 (SD 47.73); median 13.98 | |||||||
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Kaga et al [55] | Japan (2016) | General population (305) | Mean and median not reported | 37 | An internet-based telecare service for older adults, which connected the television at users’ homes to the internet: health care information was displayed on the television; if the television was not used for 3 days, a telephone call would be made to the user, and if they did not answer the call, neighborhood associations and civil servant committees would visit them to ensure that they were fine | Double-bounded dichotomous choice; ex ante; all zeros included | Mean 8.58; median 4.57 | |||||||
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Ngan et al [56] | Vietnam (2017) | Smokers who intended to quit (433) | Mean 33 | 0.8 | An SMS text messaging–based smoking cessation service: SMS text messages with relevant health information, suggestions for controlling and preventing cravings, and encouragement were sent to users 2 to 4 times a day for 6 weeks | Single-bounded dichotomous choice; ex ante; all zeros included | Mean 59.99 (95% CI 46.92-73.07) | |||||||
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Raghu et al (1) [57] | United States (2013-2014) | Patients waiting for general consultation (214) | Mean and median not reported | Not reported | A teledermoscopy service: a clinician at a health center used a smartphone (with a Canfield Dermscopefield) to capture images of skin lesions and send them to a dermatologist, who then wrote a medical note and sent it to the clinician | Double-bounded dichotomous choice; ex ante; all zeros included | Mean 63.12 (SD 44.66); median 55.77 | |||||||
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Raghu et al (2) [57] | United States (2013-2014) | Patients with skin lesions (41) | Mean and median not reported | Not reported | Same as Raghu et al (1) [57] | Double-bounded dichotomous choice; ex ante; all zeros included | Mean 59.81 (SD 30.33); median 54.83 | |||||||
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Ramchandran et al [58] | United States (2017) | Patients with diabetes (23) | Mean 56 | 52 | A teleophthalmology service: a technician or nurse used a nonmydriatic fundus camera to take photos of the patient’s eye and send them to an ophthalmologist, who then replied with a diagnosis and recommended follow-up care | Payment scale; ex ante; all zeros included | Mean 29.96 (SD 8.53) | |||||||
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Rochat et al [59] | Switzerland (2014) | People visiting a travel clinic (162) | Mean and median not reported | 53 | A telemedicine service for travelers providing pretravel information; medical advice for upcoming trips; and health advice when the traveler was abroad through telephone calls, video calls, or emails | Not reported; ex ante; all zeros excluded | Median 57.10 (IQR 34.26-57.10) | |||||||
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Ruby et al [60] | United States (2008) | Adolescents with persistent subthreshold depression (34) | Mean 17 | 57 | An internet-based depression prevention intervention for adolescents: 14 modules for depression prevention were provided through a website | Not reported; ex post; all zeros included | Median 50.15 (IQR 19.59-62.68); range 0-626.84 | |||||||
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Shariful Islam et al [61] | Bangladesh (2013-2014) | Patients with type 2 diabetes (352) | Mean 50 | 56 | An SMS text message–based health service for patients with type 2 diabetes, which provided medication reminders and relevant health information (eg, diabetes complications and recommended diet and physical activities) through SMS text messages | Open-ended; ex ante; all zeros included | Median 0.88 (IQR 1.99) | |||||||
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Stahl et al [62] | United States (2007-2008) | Patients visiting a primary care physician (101) | Mean 46 | 60 | An internet-based primary care service: a primary care physician took the patient’s medical history, conducted a visual inspection, decided on treatment, and arranged follow-up care through videoconferencing | Payment scale; ex post; all zeros included | Mean 25.71 (SD 15.88)c | |||||||
| Contingent valuation studies that reported WTP as monthly payments: WTP per month (n=9) | |||||||||||||||
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Cocosila et al [63] | Canada (2006-2007) | General population (51) | Median 21 | 57 | An SMS text message–based health reminder service: users received SMS text messages reminding them to take vitamin C pills | Open-ended; ex post; no zero responses | Median 5.25; range 0.52-31.47 | |||||||
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Contreras-Somoza et al [64] | Spain, Serbia, Netherlands, France, Israel, Italy, or Slovenia (not reported) | Patients aged >60 years with mild cognitive impairment (30) | Mean 73.3 | 60 | An internet-based information and communication technology platform (ehcoBUTLER system) for older people: the platform hosted several social and health apps to support the daily activities of older people and improve their health, quality of life, and independence | Not reported; ex ante; all zeros excluded | Median 14.64 | |||||||
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Jacobs et al [65] | Belgium (2009) | General population (135) | Mean 41 | 34 | A cardiovascular disease prevention program with internet-based components: the program comprised cardiovascular risk assessment, communication, follow-up care, a website providing health information on cardiovascular disease, advice on physical activity and diet, guidelines for behavioral changes, and individual coaching by a health psychologist | Single-bounded dichotomous choice+payment scale; ex post; all zeros included | Mean 13.41 (SD 14.42); median 5.64 | |||||||
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Rasche et al [66] | Germany (2017) | General population (96) | Mean 63.8 | 51 | A mobile app for fall prevention: the app had features such as detecting the risk of falling, recommendations for reducing this risk, storing other health-related data, and providing advice on how to prevent and respond to a fall | Open-ended; ex ante; all zeros included | Median 7.41 (IQR 14.83); range 0-118.61 | |||||||
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Somers et al (1) [34] | United Kingdom (2015) | General population (1697) | Mean 47 | 51 | A mobile app for improving well-being outcomes: the app had features such as calling and messaging friends or families or local health care providers, setting health goals, tracking health status, sharing health data, and receiving information about the local community | Open-ended; ex ante; all zeros included | Mean 24.31; median 7.46; range 0-1344.36 | |||||||
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Somers et al (2) [34] | United Kingdom (2015) | General population (305) | Mean 48 | 72 | Same as Somers et al (1) [34]. | Open-ended; ex ante; ell zeros included | Mean 20.13; median 7.46; range 0-896.62 | |||||||
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Tran et al [67] | Vietnam (2012) | Patients with HIV or AIDS (1016) | Mean 35.4 | 36 | A mobile phone–based medication reminder service for patients with HIV: SMS text messages, telephone calls, or automated voice calls were used to remind patients to take their medication on time | Not reported; ex ante; all zeros included | Mean 8.42 | |||||||
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Tsuji et al [68] | Japan (not reported) | General population (291) | Mean and median not reported | Not reported | A telehealth system for older people: health-related data such as blood pressure, oxygen saturation, heart rhythm, electrical activity, and heart rates were measured at the user’s home and sent to a remote clinic where nurses studied them and reported any unusual symptoms to the user and physicians; monthly health reports were created and sent to users | Bidding game; ex post; all zeros included | Mean 45.64 | |||||||
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Tsuji et al [69] | Japan (not reported) | General population (145) | Mean 74 | 74 | Same as Tsuji et al [68] | Bidding game; ex ante; all zeros included | Mean 29.68 | |||||||
aWTP: willingness to pay.
bPPP: purchasing power parity.
cThe WTP values were obtained by combining the WTP values for subgroups, as reported in the articles.