telemedicine , broadly defined as the use of medical information exchanged from one site to another via electronic communications to improve a patient s clinical health status , has been expected to improve simultaneously the cost of , quality of , and access to healthcare .
there are over 80 systematic reviews on the effectiveness of telemedicine and more than 20 of them reporting conclusively that telemedicine is effective   in such areas as mental health [ 3 - 5 ] and management of chronic diseases [ 6 - 8 ] including diabetes , heart failure , and elderly care
. however , previous systematic reviews on the economic evaluation of telemedicine , based on study populations in the us , the uk , and australia , show there is no conclusive evidence that telemedicine interventions are cost - saving or cost - effective compared to conventional health care [ 11 - 14 ] . in many countries
, it has been reported that a large number of telemedicine programs have been started on a trial basis but discontinued for larger scale implementation due to lack of sustainable financial sources [ 15 - 19 ] .
this is mainly because most insurers do not reimburse new types of healthcare delivery [ 20 - 22 ] .
for this reason , several studies have stated that comprehensive cost - effectiveness studies are essential in justifying insurer coverage and reimbursement for telemedicine in the future .
japan has faced a growing proportion of elderly people amidst a declining overall population . in 2014 , the proportion of the population aged 65 or older was estimated to be 25.9%the highest proportion in the world .
currently , two major healthcare issues in japan are the increasing total cost of healthcare and the uneven distribution of healthcare resources .
based on the budget records issued by japan s ministry of finance , we calculated public expenditure for development and pilot trials of health information technology , including telemedicine , from 2008 to 2014the result was $ 1.5 billion . despite such enormous amounts in public subsidies for telemedicine ,
the literature indicated serious concern about the financial sustainability of telemedicine . among the studies reporting the effectiveness of telemedicine experiments around the country , only a small subset of these studies conducted an economic evaluation .
the absence of a cohesive body of rigorous economic evaluation studies may be one of the key obstacles to the widespread adoption , proliferation , and funding of telemedicine programs [ 9,28 - 30 ] .
this study s aim was to conduct a systematic review to identify and analyze the published economic evaluations on telemedicine in japan .
this qualitative assessment has three objectives : ( a ) to identify whether , and in what areas , telemedicine was evaluated to achieve a favorable level of economic efficiency , that is , whether it was cost - saving or cost - effective in japan ; ( b ) to assess the methodological rigorousness of the economic evaluations ; and ( c ) to discuss future studies necessary to improve the general financial sustainability of telemedicine .
this article focuses on telemedicine in broader health areas to make the results more comprehensive . specifically , this study gathered economic evaluations of telemedicine connecting 
non - specialized physicians and specialized physicians ,   physicians and patients ,  and  public health nurses and patients .
 we searched the following databases : pubmed / medline , web of science , ieee xplore , ichushi - web database ( the largest japanese health database ) , and cinii articles ( the largest japanese database in all academic fields ) .
all peer - reviewed articles published between january 1 , 2000 and december 31 , 2014 in english and japanese were selected if they included any type of economic evaluation in monetary terms .
the inclusion criteria regarding economic evaluation were full economic evaluation   ( i.e. , cost - minimization analysis [ cma ] , cost - effectiveness analysis [ cea ] , cost - utility analysis [ cua ] , cost - benefit analysis [ cba ] ) , cost - only analysis , or benefit - only analysis .
the exclusion criteria were articles that described only effectiveness or benefit in non - monetary terms and articles available only in abstract form .
table 1 shows the different and exact combinations of keywords , relating to economic evaluation and telemedicine , used in this research .
the selection process for the articles involved reading the titles and abstracts of the results obtained by one of the authors .
after duplicate articles were deleted , all abstracts were read for relevance based on the inclusion and exclusion criteria .
the relevant full - text articles were then obtained and thoroughly read by two authors .
a classification of the telemedicine types , economic - analysis types , study designs , study populations , time frames , and the selection for the final appraisal were obtained by reading both the abstracts and the entire articles . in case of any disagreement
, the two authors discussed the article and one designated author made the final decision . in order to compare a variety of studies conducted in different time periods
, we made a purchasing power parity adjustment and converted all costs to 2014 us dollars using the consumer price index .
we critically assessed the methodological rigorousness of the economic evaluation for each article based on the latest version of the checklist developed by drummond et al . .
this checklist was chosen partly because it was one of the most widely used assessment tools in this area , e.g. , this checklist s older version was known and widely used as  the bmj check - list  .
the most recent version of this checklist , published in 2015 , contains 87 items under ten headings ( detailed in table 2 ) .
assessors are asked to check either  yes ,   no ,  or  not applicable 
( n / a ) for each of ten subheadings according to the relative importance subjectively conferred to each item under each subheading .
this checklist concentrates on full economic evaluations , but could also be used for partial economic evaluations , reports , and commentaries on economic evaluations . if items were not applicable to a specific study , a
miki akiyama and byung - kwang yoo graded three studies using the criteria in order to reach consensus on the interpretation of the criteria , and miki akiyama graded the remaining papers . when a reviewed study reported cost and benefit but did not report the benefit - to - cost ratio ( bcr ) [ 34 - 36 ] , we made a supplemental estimation of bcr by dividing the reported financial benefit by the reported cost .
the financial benefit was estimated as the reduced medical care expenditure without assigning any monetary value for an improvement in health outcome .
we searched the following databases : pubmed / medline , web of science , ieee xplore , ichushi - web database ( the largest japanese health database ) , and cinii articles ( the largest japanese database in all academic fields ) .
all peer - reviewed articles published between january 1 , 2000 and december 31 , 2014 in english and japanese were selected if they included any type of economic evaluation in monetary terms .
the inclusion criteria regarding economic evaluation were full economic evaluation   ( i.e. , cost - minimization analysis [ cma ] , cost - effectiveness analysis [ cea ] , cost - utility analysis [ cua ] , cost - benefit analysis [ cba ] ) , cost - only analysis , or benefit - only analysis .
the exclusion criteria were articles that described only effectiveness or benefit in non - monetary terms and articles available only in abstract form .
table 1 shows the different and exact combinations of keywords , relating to economic evaluation and telemedicine , used in this research .
the selection process for the articles involved reading the titles and abstracts of the results obtained by one of the authors .
after duplicate articles were deleted , all abstracts were read for relevance based on the inclusion and exclusion criteria .
the relevant full - text articles were then obtained and thoroughly read by two authors .
a classification of the telemedicine types , economic - analysis types , study designs , study populations , time frames , and the selection for the final appraisal were obtained by reading both the abstracts and the entire articles . in case of any disagreement
, the two authors discussed the article and one designated author made the final decision . in order to compare a variety of studies conducted in different time periods
, we made a purchasing power parity adjustment and converted all costs to 2014 us dollars using the consumer price index .
we critically assessed the methodological rigorousness of the economic evaluation for each article based on the latest version of the checklist developed by drummond et al . .
this checklist was chosen partly because it was one of the most widely used assessment tools in this area , e.g. , this checklist s older version was known and widely used as  the bmj check - list  .
the most recent version of this checklist , published in 2015 , contains 87 items under ten headings ( detailed in table 2 ) .
assessors are asked to check either  yes ,   no ,  or  not applicable  (
n / a ) for each of ten subheadings according to the relative importance subjectively conferred to each item under each subheading .
this checklist concentrates on full economic evaluations , but could also be used for partial economic evaluations , reports , and commentaries on economic evaluations . if items were not applicable to a specific study , a 
miki akiyama and byung - kwang yoo graded three studies using the criteria in order to reach consensus on the interpretation of the criteria , and miki akiyama graded the remaining papers .
when a reviewed study reported cost and benefit but did not report the benefit - to - cost ratio ( bcr ) [ 34 - 36 ] , we made a supplemental estimation of bcr by dividing the reported financial benefit by the reported cost .
the financial benefit was estimated as the reduced medical care expenditure without assigning any monetary value for an improvement in health outcome .
the initial screening of the electronic databases retrieved 138 titles and abstracts ; after the removal of duplicates and irrelevant titles , 64 abstracts remained for screening and 29 potentially eligible full - text articles were obtained .
we excluded 12 articles after reading the full text , which were judged to meet the exclusion criteria .
two were general reviews of the situation in asia , one was a review on the methodology of economic evaluation , four were benefit analyses using the same survey data , and five papers were not peer reviewed .
eventually , 17 peer - reviewed articles containing any form of economic appraisal in monetary terms remained .
table 3 summarizes the characteristics and key findings of the selected studies . among these studies ,
12 were published in english [ 34 - 45 ] and five in japanese [ 27,46 - 49 ] .
the service settings of telemedicine were categorized into two major types : those connecting physicians for specialist consultations ( the md  md setting ) [ 34,35,37 - 39,49 ] and those connecting healthcare providers and patients [ 27,36,40 - 48 ] , which were further sub - categorized into settings connecting physicians and patients at home ( the md  patient setting ) , and those connecting public health nurses and patients at home ( the phnrs  patient setting ) .
md settings included dermatological consultation , pediatric medical consultation , emergency radiotherapy for malignant spinal cord compression , real - time computed tomography ( ct ) scan indication , teleradiology , and telepathology .
all of the 11 settings connecting healthcare providers and patients  that is , the md  patient setting and phnrs  patient setting  dealt with home - based systems with two types of functions .
one function type is a stand - alone real - time video conference system for palliative care for cancer patients without continuous monitoring of vital signs .
the other type , evaluated by 10 articles [ 27,40 - 48 ] , monitors vital signs with equipment such as an automated sphygmomanometer and a simple electrocardiograph for home . healthcare providers
this type of system targeted lifestyle - related diseases such as high blood pressure , diabetes , stroke , and heart failure among fragile elderly patients .
regarding the types of economic evaluation , they were classified into four types ; three were cba , which provide the most useful policy implication , that is , benefit measured by monetary value compared to input cost of telemedicine .
three studies were categorized as cma [ 35 - 37 ] , which estimate the cost reduction by telemedicine compared to a control group  both telemedicine and control groups achieved the same level of health outcome .
four studies [ 27,43 - 45 ] measured medical expenditure saved due to telemedicine , without calculating the input telemedicine cost or showing equal health outcomes .
the remaining seven studies [ 38,39 , 41,42,46,47,49 ] measured willingness - to - pay ( wtp ) for using telemedicine .
md settings , one clinical efficacy study presented detailed estimates of both the costs and benefits of telemedicine in emergency radiotherapy for malignant spinal cord compression ( mscc ) , connecting between a university hospital and 10 rural hospitals . since this study did not report the bcr , we calculated the ratios to range from 4.67 to 13.40 .
one cma study on dermatology consultation   reported cost - saving of $ 330 per person per week .
this study s two - way sensitivity analysis indicated that the cost - saving results were sensitive to the two key parameters of travel time and consultation time . assuming that travel time was 60 minutes and consultation time was five minutes ( based on expert opinions from japanese dermatologists ) , we calculated the bcr to be 1.53 .
this study estimated that teleconsultation contributed to cost - saving of $ 144 per reading by avoiding unnecessary enhanced ct scans .
one survey   estimated the benefits of specialist teleconsultation in pediatric emergency care for primary care physicians in rural , underserved areas .
these benefits were measured by inquiring about wtp among parents of children in two rural towns , that is , $ 31.40 to $ 33.60 per emergency department visit .
there were two studies conducted by one study group to estimate medical providers wtp for teleradiology and telepathology .
these two studies applied different statistical methods for the same set of survey data obtained from healthcare providers across japan , who used either teleradiology or telepathology in an md  md setting .
their wtp estimates were $ 489 to $ 510 for teleradiology and $ 1063 to $ 1111 for telepathology per person per year .
one cma study   on home - palliative care in an md  patient setting reported that telemedicine could reduce the frequency of physician visits from twice to once a week .
the cost - saving of home palliative care with telemedicine were estimated to be $ 5000 per person per year compared to conventional home care .
a sensitivity analysis of this study showed their results to be sensitive to two parameters , the number of user patients and duration of service provided .
one study group published two cba studies on the same type of tele - homecare service operated in different regions with different financial schemes : ( a ) one region where a monthly fee was charged and ( b ) three other regions where no fee was charged because of public subsidies . under the former scheme
, the bcr was calculated to increase monotonically over time , that is , 1.07 ( 6-year operation ) and 1.28 ( 11-year operation ) , using wtp estimates among patients in this region . under the latter scheme , the bcr estimates in the three regions ranged from 0.54 to 0.61 , indicating that telehomecare was not cost - saving .
there were four studies reporting medical expenditure saved by telehomecare connecting public health nurses and the elderly with chronic diseases in one region [ 27,43 - 45 ] .
based on the claims data , these studies showed that treatment periods were shortened by telemedicine .
their estimates of reduced medical expenditure ranged from $ 148 to $ 629 per case per year for lifestyle diseases [ 27,43 - 45 ] . however , the input costs of telehomecare were not shown in these four studies .
a single research team produced three survey studies and measured patients wtp for a telehomecare system that combines vital - signs monitoring and doctor consultation .
the wtp estimates were $ 288 , $ 480 , and $ 520 per case per year , depending on three analytical methods .
there was only one study conducted in an urban area to estimate users wtp for home tele - health monitoring .
this study , published in 2012 , showed wtp as low as $ 109 per patient per year .
table 4 summarizes our quality assessment of reviewed studies in terms of the ten criteria of the well - established checklist from drummond et al . .
there were only four studies   that met more than eight criteria , and eleven studies met only three or fewer criteria .
studies of cba and cma tended to meet more criteria than studies that measured only the benefits of telemedicine .
only two studies   conducted a sensitivity analysis , and hence met the two criteria of  uncertainty estimates  and  study results including all issues of concern .
 figure 2 was created to detect a potential publication bias among the reviewed papers .
a bold vertical line in this figure represents a threshold bcr value of one ( also called a break - even point ) .
a plot located rightward of this threshold vertical line indicates a favorable economic efficiency level for a telehealth program evaluated in the published study .
since the plots were skewed to the right of the threshold vertical line ( i.e. , bcr greater than one ) , figure 2 implies a moderate bias toward publishing more studies with a higher bcr estimate for a tele - health intervention .
it should be noted that our interpretation regarding such potential publication bias has limited validity due to the small number of publications with bcr estimates .
the initial screening of the electronic databases retrieved 138 titles and abstracts ; after the removal of duplicates and irrelevant titles , 64 abstracts remained for screening and 29 potentially eligible full - text articles were obtained .
we excluded 12 articles after reading the full text , which were judged to meet the exclusion criteria .
two were general reviews of the situation in asia , one was a review on the methodology of economic evaluation , four were benefit analyses using the same survey data , and five papers were not peer reviewed .
eventually , 17 peer - reviewed articles containing any form of economic appraisal in monetary terms remained .
table 3 summarizes the characteristics and key findings of the selected studies . among these studies ,
12 were published in english [ 34 - 45 ] and five in japanese [ 27,46 - 49 ] .
the service settings of telemedicine were categorized into two major types : those connecting physicians for specialist consultations ( the md  md setting ) [ 34,35,37 - 39,49 ] and those connecting healthcare providers and patients [ 27,36,40 - 48 ] , which were further sub - categorized into settings connecting physicians and patients at home ( the md  patient setting ) , and those connecting public health nurses and patients at home ( the phnrs  patient setting ) .
md settings included dermatological consultation , pediatric medical consultation , emergency radiotherapy for malignant spinal cord compression , real - time computed tomography ( ct ) scan indication , teleradiology , and telepathology .
all of the 11 settings connecting healthcare providers and patients  that is , the md  patient setting and phnrs  patient setting  dealt with home - based systems with two types of functions .
one function type is a stand - alone real - time video conference system for palliative care for cancer patients without continuous monitoring of vital signs .
the other type , evaluated by 10 articles [ 27,40 - 48 ] , monitors vital signs with equipment such as an automated sphygmomanometer and a simple electrocardiograph for home . healthcare providers
this type of system targeted lifestyle - related diseases such as high blood pressure , diabetes , stroke , and heart failure among fragile elderly patients .
regarding the types of economic evaluation , they were classified into four types ; three were cba , which provide the most useful policy implication , that is , benefit measured by monetary value compared to input cost of telemedicine .
three studies were categorized as cma [ 35 - 37 ] , which estimate the cost reduction by telemedicine compared to a control group  both telemedicine and control groups achieved the same level of health outcome .
four studies [ 27,43 - 45 ] measured medical expenditure saved due to telemedicine , without calculating the input telemedicine cost or showing equal health outcomes .
the remaining seven studies [ 38,39 , 41,42,46,47,49 ] measured willingness - to - pay ( wtp ) for using telemedicine .
md settings , one clinical efficacy study presented detailed estimates of both the costs and benefits of telemedicine in emergency radiotherapy for malignant spinal cord compression ( mscc ) , connecting between a university hospital and 10 rural hospitals . since this study did not report the bcr , we calculated the ratios to range from 4.67 to 13.40 .
one cma study on dermatology consultation   reported cost - saving of $ 330 per person per week .
this study s two - way sensitivity analysis indicated that the cost - saving results were sensitive to the two key parameters of travel time and consultation time . assuming that travel time was 60 minutes and consultation time was five minutes ( based on expert opinions from japanese dermatologists ) , we calculated the bcr to be 1.53 .
this study estimated that teleconsultation contributed to cost - saving of $ 144 per reading by avoiding unnecessary enhanced ct scans .
one survey   estimated the benefits of specialist teleconsultation in pediatric emergency care for primary care physicians in rural , underserved areas .
these benefits were measured by inquiring about wtp among parents of children in two rural towns , that is , $ 31.40 to $ 33.60 per emergency department visit .
there were two studies conducted by one study group to estimate medical providers wtp for teleradiology and telepathology .
these two studies applied different statistical methods for the same set of survey data obtained from healthcare providers across japan , who used either teleradiology or telepathology in an md  md setting .
their wtp estimates were $ 489 to $ 510 for teleradiology and $ 1063 to $ 1111 for telepathology per person per year .
one cma study   on home - palliative care in an md  patient setting reported that telemedicine could reduce the frequency of physician visits from twice to once a week .
the cost - saving of home palliative care with telemedicine were estimated to be $ 5000 per person per year compared to conventional home care .
a sensitivity analysis of this study showed their results to be sensitive to two parameters , the number of user patients and duration of service provided .
one study group published two cba studies on the same type of tele - homecare service operated in different regions with different financial schemes : ( a ) one region where a monthly fee was charged and ( b ) three other regions where no fee was charged because of public subsidies . under the former scheme ,
the bcr was calculated to increase monotonically over time , that is , 1.07 ( 6-year operation ) and 1.28 ( 11-year operation ) , using wtp estimates among patients in this region . under the latter scheme , the bcr estimates in the three regions ranged from 0.54 to 0.61 , indicating that telehomecare was not cost - saving .
there were four studies reporting medical expenditure saved by telehomecare connecting public health nurses and the elderly with chronic diseases in one region [ 27,43 - 45 ] .
based on the claims data , these studies showed that treatment periods were shortened by telemedicine .
their estimates of reduced medical expenditure ranged from $ 148 to $ 629 per case per year for lifestyle diseases [ 27,43 - 45 ] .
a single research team produced three survey studies and measured patients wtp for a telehomecare system that combines vital - signs monitoring and doctor consultation .
the wtp estimates were $ 288 , $ 480 , and $ 520 per case per year , depending on three analytical methods .
there was only one study conducted in an urban area to estimate users wtp for home tele - health monitoring .
this study , published in 2012 , showed wtp as low as $ 109 per patient per year .
one cma study   on home - palliative care in an md  patient setting reported that telemedicine could reduce the frequency of physician visits from twice to once a week .
the cost - saving of home palliative care with telemedicine were estimated to be $ 5000 per person per year compared to conventional home care .
a sensitivity analysis of this study showed their results to be sensitive to two parameters , the number of user patients and duration of service provided . based on the reported benefit , we calculated the bcr to be 1.93 .
one study group published two cba studies on the same type of tele - homecare service operated in different regions with different financial schemes : ( a ) one region where a monthly fee was charged and ( b ) three other regions where no fee was charged because of public subsidies . under the former scheme
, the bcr was calculated to increase monotonically over time , that is , 1.07 ( 6-year operation ) and 1.28 ( 11-year operation ) , using wtp estimates among patients in this region . under the latter scheme , the bcr estimates in the three regions ranged from 0.54 to 0.61 , indicating that telehomecare was not cost - saving . there were four studies reporting medical expenditure saved by telehomecare connecting public health nurses and the elderly with chronic diseases in one region [ 27,43 - 45 ] .
based on the claims data , these studies showed that treatment periods were shortened by telemedicine .
their estimates of reduced medical expenditure ranged from $ 148 to $ 629 per case per year for lifestyle diseases [ 27,43 - 45 ] . however , the input costs of telehomecare were not shown in these four studies .
a single research team produced three survey studies and measured patients wtp for a telehomecare system that combines vital - signs monitoring and doctor consultation .
the wtp estimates were $ 288 , $ 480 , and $ 520 per case per year , depending on three analytical methods .
there was only one study conducted in an urban area to estimate users wtp for home tele - health monitoring .
this study , published in 2012 , showed wtp as low as $ 109 per patient per year .
table 4 summarizes our quality assessment of reviewed studies in terms of the ten criteria of the well - established checklist from drummond et al . .
there were only four studies   that met more than eight criteria , and eleven studies met only three or fewer criteria .
studies of cba and cma tended to meet more criteria than studies that measured only the benefits of telemedicine .
only two studies   conducted a sensitivity analysis , and hence met the two criteria of  uncertainty estimates  and  study results including all issues of concern .
 figure 2 was created to detect a potential publication bias among the reviewed papers .
a bold vertical line in this figure represents a threshold bcr value of one ( also called a break - even point ) .
a plot located rightward of this threshold vertical line indicates a favorable economic efficiency level for a telehealth program evaluated in the published study .
since the plots were skewed to the right of the threshold vertical line ( i.e. , bcr greater than one ) , figure 2 implies a moderate bias toward publishing more studies with a higher bcr estimate for a tele - health intervention .
it should be noted that our interpretation regarding such potential publication bias has limited validity due to the small number of publications with bcr estimates .
a bold vertical line in this figure represents a threshold bcr value of one ( also called a break - even point ) .
a plot located rightward of this threshold vertical line indicates a favorable economic efficiency level for a telehealth program evaluated in the published study .
since the plots were skewed to the right of the threshold vertical line ( i.e. , bcr greater than one ) , figure 2 implies a moderate bias toward publishing more studies with a higher bcr estimate for a tele - health intervention .
it should be noted that our interpretation regarding such potential publication bias has limited validity due to the small number of publications with bcr estimates .
to our knowledge , this is the first systematic review to summarize the economic efficiency of japanese telemedicine services and to examine the methodological rigorousness of the economic evaluation studies conducted in japan . despite the small number and the diverse quality of economic evaluations of telemedicine
, most of these evaluations indicated a favorable level of economic efficiency , that is , net cost - saving , reduced medical expenditure , and/or positive wtp . among studies on md  md live consultations in hospital settings , the most economically efficient telemedicine was emergency radiotherapy consultation about malignant spinal cord compression .
this study s results were consistent with another effectiveness study of spinal cord compression in canada , in terms of decreasing patient transfer and shortening treatment decision time .
however , the robustness of the reported bcr magnitude ( > 4.67 ) is uncertain due to the absence of sensitivity analyses .
md hospital setting was teledermatology consultation ( $ 17 160 per case per year ) .
this study addressed parameter uncertainty and indicated that whether teledermatology is cost - saving or not depends on the travel time and consultation time of physicians .
these results do not contradict the literature reporting mixed results ; that is , teledermatology cost is either lower   or higher [ 52 - 55 ] than conventional care costs . for an md  patient home
setting , bcr of telemedicine - combination home palliative care was estimated to be 1.93 , compared to the status quo .
this cma was methodologically rigorous with regard to ( a ) a clear statement of the purpose and perspective of the study , ( b ) a detailed illustration of the cost estimation , and ( c ) the implementation of a sensitivity analysis .
this study in japan is one of the few studies that explicitly indicated telemedicine to be cost - saving when used to supplement in - person home visits by physicians .
similar real - time , audio - visual communication services for home palliative care have been successfully used for some years in the us [ 56 , 57 ] and australia , while investigation in canada   and pediatric telepalliative care in australia   faced difficulties . in the us ,
the cost - saving of tele - palliative care was reported as due to a reduced number of home visits by nurses .
regarding telehomecare among the elderly with chronic diseases , two cbas reported cost - saving when implemented in one region ( bcr , 1.07 to 1.28 )   where patients wtp was the only outcome measured .
it should be noted that an identical system deployed in three other regions with public subsidies showed less economic efficiency ( bcr 0.61 ) due to lower wtps ( 37% to 71% of the similar one - region system above ) and higher system costs ( 186% to 195% of the one - region system ) .
the reason for the mixed bcr results can be partly attributed to the public subsidy rule .
the restrictive rules of public subsidy are exemplified by the prohibition on carrying over the budget to a second year , which may have caused over - utilization of the first year cost and hence ultimately decreased bcr .
the methodological rigorousness of the reviewed studies tended to deviate from the established guidelines for economic evaluations [ 31,32,61 - 63 ] .
for instance , only five studies [ 34 - 36,40,48 ] clarified the complete cost measurements of installing and operating telemedicine , which should have been compared with reduced medical expenditure due to the implementation of a telemedicine strategy such as a home telecare system ( reduced by $ 148 to $ 629 per case per year ) [ 27,43 - 45 ] and teleradiology ( $ 144 per ct reading ) .
therefore , other than these five studies , it seemed very difficult to determine the accurate economic efficiency level of telemedicine among the reviewed studies .
moreover , none of the reviewed studies implemented a cea or a cua of the telemedicine program under focus .
therefore , it is impossible to judge whether a program is reasonably cost - effective or not when it is not cost - saving .
another example of a common limitation among the reviewed studies is the absence or very limited application of a probabilistic analysis such as a monte carlo simulation in order to address the uncertainty of multiple key parameters on cost , effectiveness , and benefit , simultaneously .
in addition to the small number of total publications on the topic in focus , there are even fewer studies that examined comparable types of telemedicine technology and outcomes .
this limited number of studies prevented us from performing a quantitative summary of the literature , such as a meta - analysis .
we believe that the following types of future studies would be useful for an international audience as well as a japanese one . to convince policymakers to initiate and continue public subsidies for telemedicine
, researchers are expected to produce more methodologically rigorous empirical evidence , presented in a reader - friendly manner .
due to diverse costs and benefits depending on setting , a probabilistic analysis result is useful to report ; for example , cost - saving is achieved by telemedicine in 57% of 5000 iterations in emergency departments   and 37% of 1000 iterations in intensive care units .
moreover , hospital level administrators as well as policy - makers would find it easy to understand a concrete and realistic scenario ; for example , treating 10 acutely ill and injured children at a rural emergency department with telemedicine will lead to annual cost - saving of $ 46 620 per emergency department .
these decision makers would also appreciate specific benchmarks to achieve cost - saving , such as maximum allowable cost derived from break - even analyses .
since telemedicine in a probabilistic analysis is less likely to achieve cost - saving in 100% of iterations , a cea needs to be implemented to test whether telemedicine is reasonably cost - effective or not . to make cea results of telemedicine comparable with other types of health care
, a future study is expected to estimate an incremental cost - effectiveness ratio ( icer ) with a unit of dollar value per additional quality - adjusted life year ( qaly ) by the us expert panel on cost - effectiveness in health and medicine [ 31,61 - 63 ] .
a certain telemedicine care strategy is concluded to be cost - effective if its icer is lower than a commonly used threshold of $ 100 000 per qaly .
these estimates concerning cea are also appreciated by policymakers and insurers who are interested in maximizing health outcomes under a fixed budget .
other than improving the methodological rigorousness of economic evaluations , our review demonstrated the importance of wtp measured among users and public subsidy rules .
the measured wtp could be used as a proxy for a future user charge , which is particularly important if the wtp exceeds the actual out - of - pocket payment for telemedicine . partly because of the difference in the surveyed populations , wtp for a similar health - monitoring telemedicine care strategy declined by 75 percentage points from 2003 to 2010 .
potential reasons for the decline include the decreased japanese purchasing power due to long - term macro - economic recession and users observations of continuously falling prices in other it products and services .
thus , further studies are needed in measuring wtp under various and detailed scenarios as well as addressing the impact of public subsidy regulation on bcr .
these studies could help justify increased public financial support and hence improve the financial sustainability of telemedicine programs .
in conclusion , compared to the substantial resources deployed for more than 1000 telemedicine trials in japan , very limited resources have been deployed for the economic evaluation of telemedicine trials .
although most reviewed economic evaluations reported a favorable level of economic efficiency , their methodological rigorousness tended to vary .
further economic evaluation studies in this field are needed with more advanced methodological rigorousness and expanded research scope ( e.g. , public subsidy regulation impacts ) .
these future studies are expected to help convince various decision makers such as policymakers , insurers and hospital administrators to invest further resources in telemedicine .
consequently , the general financial sustainability of telemedicine is expected to improve in the long term .
 objectives : there is no systematic review on economic evaluations of telemedicine in japan , despite over 1000 trials implemented . our systematic review aims to examine whether japan s telemedicine is cost - saving or cost - effective , examine the methodological rigorousness of the economic evaluations , and discuss future studies needed to improve telemedicine s financial sustainability.methods:we searched five databases , including two japanese databases , to find peer - reviewed articles published between january 1 , 2000 and december 31 , 2014 in english and japanese that performed economic evaluations of japan s telemedicine programs . 
 the methodological rigorousness of the economic analyses was assessed with a well - established checklist . 
 we calculated the benefit - to - cost ratio ( bcr ) when a reviewed study reported related data but did not report the bcr . 
 all cost values were adjusted to 2014 us dollars.results:among the 17 articles identified , six studies reported on settings connecting physicians for specialist consultations , and eleven studies on settings connecting healthcare providers and patients at home . 
 there are three cost - benefit analyses and three cost - minimization analyses . 
 the remaining studies measured the benefit of telemedicine only , using medical expenditure saved or users willingness - to - pay . 
 there was substantial diversity in the methodological rigorousness . 
 studies on teledermatology and teleradiology indicated a favorable level of economic efficiency . 
 studies on telehomecare gave mixed results . 
 one cost - benefit analysis on telehomecare indicated a low economic efficiency , partly due to public subsidy rules , e.g. , a too short budget period.conclusions:overall , telemedicine programs in japan were indicated to have a favorable level of economic efficiency . 
 however , the scarcity of the economic literature indicates the need for further rigorous economic evaluation studies . 