Opportunity cost of the dermatologist’s consulting time in the economic evaluation of teledermatology

Abstract

Introduction

This study, through a systematic review and meta-analysis, has sought to demonstrate that the opportunity cost is a value to take into account in studies of economic cost in telemedicine, illustrated through the time of the dermatologist’s consultation in teledermatology and traditional consultation.

Methods

Economic evaluation studies have been identified that compare teledermatology and traditional dermatological consultation during the period 1998–2015. We carried out a meta-analysis considering the work cost and the dermatologist’s consultation time, analysing their differences. The opportunity cost represented by these differences in the dermatological remote consultation time was subsequently calculated based on the design of a cost/time variable.

Results

It was not possible to meta-analyse the cost of the dermatologist’s consultation due to insufficient standardized complete data. It was possible to carry out a meta-analysis of the consultation time, and three articles were selected (2945 patients). Teledermatology accounts for more time (7.54 min) than conventional consultation (p < 0.00001) and this difference is an opportunity cost of teledermatology of €29.25 per each remote consultation, with a unitary factor cost/time of 3.88€/minute.

Conclusions

There is no unanimity in the literature regarding which of the two procedures is cheaper; further studies with the necessary standardized variables are required. In this meta-analysis, teledermatology takes more time than a conventional dermatology consultation, which leads to an opportunity cost, increasing the total cost of consultation. The opportunity cost is a value that should be included in an analysis of economic costs, in the context of an economic assessment, when we evaluate a health activity.

Keywords

Opportunity cost economic evaluation time of consulting teledermatology

Introduction

Economic arguments have been incorporated into the healthcare field in recent years, since their assumptions are entirely applicable to conditions in modern healthcare systems.¹ First, resources are scarce. Although spending on healthcare is increasing, the needs tend to be unlimited. It is usually the case that the healthier a society is, the higher the demand for medical care, and the more medical progress is made, the higher the cost of additional improvements. Second, when resources are scarce, it is necessary to decide upon the best way to spend them. Finally, when resources are used in a specific way, the option of using them in another way is ruled out.²

Using resources in a specific way always implies a sacrifice. For economists, the concept of cost always entails the meaning of relinquishment. “Opportunity cost” is defined as the value of the best option which is waived when a choice is made.³ Telemedicine is a new technology that provides healthcare of all kinds (training, assistance, monitoring) based on information and communication technologies, which has been recognized as an organizational solution for improving the population’s access to healthcare and for professionals in general. Teledermatology was one of the services that developed most quickly, primarily in the use of images and telecommunications to provide advice from a dermatologist to other healthcare professionals, and mainly family doctors.⁴

In any economic evaluation study of teledermatology compared with conventional dermatology, there are many variables that make it difficult to design an economic study for this new technology, whether based on cost-effectiveness, cost-benefit, utility or cost reduction. Economic evaluation studies of teledermatology selecting some of these variables have appeared in the literature in recent years, with the primary goal of costs reduction (cost minimization) and cost-effectiveness analysis.⁵

A new approach to economically evaluating teledermatology compared with conventional dermatology is to ensure that the benefits obtained by selecting one option are greater than those that would have been otherwise obtained: in other words, to analyse the opportunity cost. This study aims to demonstrate the importance of the opportunity cost in the economic evaluation of the teledermatology consultation and conventional dermatology consultation, and to provide a systematic review of the literature that determines the total cost and the differences in the time spent by the professional in each of the varieties of dermatological care. The specific objectives are as follows:

To identify and obtain the following variables: the consultation time used and the costs of the consultation time for both procedures.

To apply a systematic statistical approach (meta-analysis) to calculate the differences found in these two variables between both procedures.

To calculate the opportunity cost of teledermatological consultation time.

Methods

Selection of publications

The articles sought for the meta-analysis used the following electronic databases: ISI web of knowledge, MEDLINE, EMBASE, the Cochrane Library and Scopus. Articles were identified only as RCT or controlled clinical trials in English during the period 1998–2015 using the following search strategy: “utility” or “cost-effectiveness” and “time” with “teledermatology” and “conventional dermatology”. The selection process was as follows:

Identification of all titles and abstracts by two reviewers, with discrepancies resolved by consensus.

Selection of items for the study. After all the abstracts had been identified by consensus, two reviewers chose those meeting the following inclusion criteria: (a) economic evaluation and cost-analysis studies, analysis of minimization of costs, cost-effectiveness analysis, cost-utility analysis, cost-benefit analysis; (b) operations on adult patients, over 18 years old; (c) comparative studies of teledermatology and conventional dermatology; (d) variables studied (at least): consultation time and cost of consultation; (e) when the same author had published more than one paper on the same study, the highest-quality or the most recent paper was selected. The abstracts selected were obtained from the corresponding articles, and those from communications to congresses, reviews, letters, editorials and case reports were discarded.

The exclusion criteria were: non-comparative or non-RCT; duplicate studies appearing in various journals.

Two reviewers examined the quality of the publications selected by the CHEC list of Evers et al.⁶ for studies of economic evaluations, and then obtained the data needed to conduct the meta-analysis of each item.

The CEBM (Centre for Evidence-Based Medicine) critical appraisal tools of the University of Oxford were used to evaluate the articles included in the meta-analysis study.⁷

Statistical study

Systematic statistical approach (meta-analysis)

We considered each article included in the study comparing teledermatology with conventional dermatology as response variables, in order to measure the magnitude of the effect, the cost of the consultation (in Euros or the equivalent currency in the year of publication) and the consultation time (min), according to the following definitions:

Cost of the consultation: the direct medical cost of the time spent by the dermatologist on their first visit to diagnose the disease and decide upon treatment. This is the percentage of the salary that corresponds to the time taken in the work done by the dermatologist.

Consultation time: the overall time spent by the dermatologist with the patient on primary care consultation (anamnesis, diagnostic and management plan), either conventionally or by teledermatology.

The meta-analysis of both cost and time (if applicable) would include the studies for which it was possible to obtain the mean, standard deviation and the sample size of each group (conventional dermatology consultation vs. teledermatology consultation). The standardized mean difference was considered as a measure of the effect of the sample size for cost, as the same currency was not used in all the articles included, and mean difference was used for time (minutes). A confidence interval of 95% (CI) of the sample size was estimated in both cases. First, an analysis of the statistical heterogeneity between the studies using the Higgins and Thompson test (I²), and Galbraith’s graph was performed to show the dispersion between the studies, and the χ² test with p < 0.005 was carried out to determine heterogeneity with statistical significance. If we found sufficient data from the articles selected, a meta-analysis was subsequently conducted using the Z test to analyse the statistical significance. If high clinical heterogeneity (I²> 50%) was observed, the estimate of the effects was calculated using the random effects model proposed by the DerSimonian and Laird method. If no significant heterogeneity was observed, the fixed-effects model was applied using the inverse variance method. An analysis of the sensitivity of the results (influence graphics) and publication bias (tests of Begg and Egger and the Funnel chart) was finally carried out.

All the statistical analysis was performed with the Epidat 4.1 and Review Manager Software 5.3 statistical packages developed by the Cochrane Collaboration institution.

Opportunity cost calculation

After estimating the difference in consultation times between the two techniques by means of meta-analysis, the estimated opportunity cost represented by these time differences was calculated. It is assumed that a dermatologist would be able to perform additional activities, including more visits, in the time left over from applying other forms of dermatological care.

To do so, it is necessary to calculate an actual value of the time saved by applying the more efficient dermatological procedure, which in our case corresponds to a cost/period unit factor (€/min) we will call ξ. Data from the studies in the literature review have been used to calculate this factor. Time and cost data relating to the period 1998–2015 for conventional dermatology were extracted from these studies. The extracted cost of the selected article has been updated to 2015, adding to the initial value released corresponding to the cumulative inflation data of the World Bank for countries where there have been selected in this study work, from year increase publication.⁸ The value of the unit/time ξ factor is therefore calculated by dividing the average cost of the procedure of the conventional dermatology consultation in € by the average duration of conventional dermatology consultation time in minutes. This result provides the opportunity cost of the teledermatology consultation, from the value of ξ multiplied by the excess average time (estimated value in the meta-analysis for the variable time) taken by the teledermatology consultation data.

Results

Search strategy and selection of articles

In total, 106 items were obtained in the literature search performed for the selected period. After reviewing the titles and reading the abstracts, eight were discarded (due to being duplicates or unsuitable for our purposes). For the selected 98 items we obtained the full text, and after being read by two reviewers and after the application of the Evers et al. CHEC list, eight articles^9–16 were included in the review. Three works were included in the meta-analysis of the operating time and eight works in the calculation of the opportunity cost; no meta-analysis of the cost was performed as the papers did not contain sufficient minimum data. None of the selected works carried out a full economic evaluation. All of them comparatively analysed teledermatology consultation and conventional dermatology consultation (see Figure 1).

Figure 1.

Flow chart of the systematic review.

The articles selected for the meta-analysis of the time come from three countries: Italy, Austria and the United Kingdom. We present the most important aspects of these studies in Table 1.

Table 1.

Main points of the studies included in the meta-analysis.

Study	Wootton et al.⁹	Jacklin et al.¹⁰	Nami et al.¹¹
Participating centres and country	Four health centres and two hospitals in North Ireland	Two hospitals in Greater London and Shrewsbury and 29 family doctors in London and Wales	University hospitals of Graz (Austria) and Siena (Italy)
Experience in telemedicine	Yes	Yes	Yes
Aim of the study	RCT video-teledermatology and conventional consultation	RCT video-teledermatology and conventional consultation	Comparison store-and-forward teledermatology and conventional consultation
Variables analysed	Clinical outcome and costs	Costs to NHS and patient	All the times taken by the dermatologist when doing his work
Conclusions	Teledermatology is not cost-effective compared with conventional dermatology	Higher cost for NHS and lower cost for the patient when teledermatology is used	Store-and-forward teledermatology involves additional time in preparing and transmitting the information

Statistical study

After selecting studies for which the mean, deviation and sample size of each of the groups could be extracted, three studies for the analysis of consultation time were included. The other studies (n = 36) could be not meta-analysed due to a lack of information provided by their authors.

Dermatologist consultation time

The test to evaluate heterogeneity showing statistical significance of p < 0.001 and the Higgins-Thompson statistic indicates a proportion of variation between the studies of 96.3% (Table 2). The lack of homogeneity between studies meant that it was necessary to calculate the estimate of the effect using a random effects model according to the DerSimonian and Laird method.

Table 2.

Heterogeneity of the time (min) between the studies included.

Q statistic (χ²)	df	Sig. level
36.2305	2	0.0000
Variance inter-studies	0.1232
Variance intra-studies	0.0047
Coefficent I²	0.9630
Variation coef. inter-studies	0.3254

Table 3 and Figure 2 show the results of the meta-analysis of the operating time. The effects test indicates Z = 29.25 (p < 0.00001), with a longer consultancy time when teledermatology is used. We can therefore conclude from the meta-analysis of the consultation time that the consultation time is 7.54 minutes longer when teledermatology is used. The sensitivity analysis (Table 4 and Figure 3) shows that the most influential study is by Wootton et al.⁹ Its conclusion is opposite to the other two studies included, and would imply a greater relative change if removed from the study. Likewise, in terms of the percentages of change shown in the table, none of the studies included should not be included in the meta-analysis, as they all provide it with information.

Figure 2.

Tree graph of dermatologist’s consultation time (min).

Figure 3.

Graph of influence of the dermatologist’s consultation time (min.)

Table 3.

Meta-analysis of the consultation time (min).

Studies	Year	n	d*	95%CI
Wootton et al.⁹	2000	204	1.80	[0.17, 3.43]
Jacklin et al.¹⁰	2003	2094	8.10	[7.47, 8.73]
Nami et al.¹¹	2015	647	8.30	[7.30, 9.30]
Random effects		1945	7.54	[7.04, 8.05]
Test for overall effect: Z = 29.25 (p < 0.00001)

d = Mean difference between the time of consultation of the CDC and TDC

Table 4.

Sensitivity analysis of the dermatologist’s consultation time (min.)

Included study	Year	n	d	95%CI	Relative change %
Wootton et al.⁹	2000	2741	1.1813	[1.0047,1.3579]	28.54
Jacklin et al.¹⁰	2003	851	0.8020	[−0.1621,1.7662]	−12.73
Nami et al.¹¹	2015	2298	0.7155	[−0.0694,1.5004]	−22.14
Global		2945

d = Mean difference between the time of consultation of the conventional dermatology consultation and teledermatology consultation

Finally, in the publication bias analysis, both the Begg test (Z = 0.000, p = 1000 > 0.05), and the Egger test (t = −0.7478, p = 0.5912 > 0.05), showed the absence of publication bias.

Estimation of the opportunity cost

To calculate the opportunity cost, we first obtained the average consultation time in all the studies included in the review (both from those included in the meta-analysis and those that were not) when the procedure was conventional dermatology consultation. We found that this average was 13.83 minutes. The average cost of each consultation according to the studies included in the review was €43.43, and updated to the cumulative inflation data was €53.65. To calculate this meaning, we first transformed each cost in the currency stated in the study into Euros for standardization. The value of the cost/time unit factor was consequently x = 3.88 €/min, meaning that considering the time difference estimated in the meta-analysis, 7.54 minutes more in teledermatology consultation, there is an opportunity cost of €29.25 in each dermatological remote consultation (Table 5).

Table 5.

Opportunity cost of teledermatology consultation

Studies	Year	Country	Cost (€)	Cost updated (€)*	Time (min.) CDC
Eminovic et al.¹²	2010	Holland	54.4	59.94	10
Wootton et al.⁹	2000	UK	47.73	63.57	13.9
Persaud et al.¹³	2005	Canada	63.46	77.67	19
Nami et al.¹¹	2015	Italy			15
Jacklin et al.¹⁰	2003	UK	46.88	60.89	11.8
Chan et al.¹⁴	2000	Hong Kong	4.66	6.21	5.5
Loane et al.¹⁵	2001	Australia	–		13.9
Loane et al.¹⁶	2001	New Zealand	–		21.6
Mean cost (€)			43.43	53.65
Mean time CDC (min)					13.83
ξ (€/min)				3.88
Opportunity cost TDC (€)				29.25

Cost updated to 2015. World Bank data.

CDC: conventional dermatology consultation; TDC: teledermatology consultation

Discussion

Economic considerations are crucial when planning a telemedicine programme and deciding whether or not to adopt that programme. Telemedicine operations provide similar clinical results to conventional care.^17,18 However, reasons considered important when deciding to adopt telemedicine technology include whether there are economic advantages compared with comparable or superior clinical outcomes, or whether the cost-effectiveness relations are favourable when clinical superiority is proven despite the higher costs.

When we analysed of the costs of teledermatology, the main problem in an economic assessment is which costs to consider. The costs of teledermatology have two main components: healthcare costs (variable and fixed) and non-health costs. Fixed healthcare costs are the communication infrastructure, and variable healthcare costs are the time required by the specialist to operate the equipment and the cost of the time of the doctor dealing with the teledermatology consultation. Non-healthcare costs are those related to societal costs arising from work time lost by workers and the loss of productivity and the cost of transport to the dermatologist’s consultations. In some circumstances,¹⁹ a third costs heading is added, derived from public health systems (federal or regional governments and management of health organizations): these costs relate to sub-contracting with private entities or costs arising from the privatization of public health management.

This means that telemedicine operations require a dedication of time by the healthcare professional in terms of the total calculation of hours spent at the health organization where he/she works. This leads to a specific labour cost which can be calculated in units of cost/time and which can generate an opportunity cost. In this study, based on a meta-analysis, we have aimed to show that the opportunity cost of the consultation time spent by the dermatologist is a value that should be included in the economic costs in teledermatology studies, since it provides important information about the economic value that is lost when an option that is not the most profitable is chosen.

The meta-analysis, which followed the indications of PRISMA,²⁰ had limitations which are highlighted in the systematic reviews related to the analysis of costs of the teledermatology and telemedicine in general,^5,21,22 for three reasons. The first relates to the economic impact of teledermatology as a complex process in which various economic, social and political actors are combined with numerous data with no homogeneous standardization between them, making it difficult to obtain definitions and content of common and standardized variables. The second is a consequence of the lack of methodologically rigorous economic studies published on teledermatology.²³ The third is related to the incomplete publication of data for each variable (lack of standard deviation, calculation of the median size of the sample, etc.) or that some costs are estimated (especially those related to transporting the patient to the consultation and the loss of work time). These disadvantages mean that the meta-analysis of time and not the cost of dermatologist’s consultation was performed for both conventional dermatology consultation and teledermatology consultation using the minimum number of papers to give the study statistical validity.

Nevertheless, it was possible to select enough dermatology consultation costs data to calculate the opportunity cost. As a result, and based on the results of studies that systematically reviewed teledermatology costs or compared the costs of teledermatology with conventional dermatology, whose results are varied disparate and contradictory,^23,24 it is as yet impossible to conclude which one costs the health system more.

In the analysis of the dermatologist’s consultation time we found that teledermatology consultation accounted for 7.54 minutes more on average in each remote consultation compared with conventional dermatology consultation, in a total of 2945 patients included in the meta-analysis. This difference is significant. The literature contains no other similar meta-analyses, and therefore based on the results presented here, and including the literature published up to 2015, it should be considered that teledermatology consultation takes more time than conventional dermatology consultation in the first consultation for diagnosis and treatment of the dermatological lesion. The reasons for this difference are the longer time spent due to using teledermatology consultation software, and the differences in capturing lesions, which are three-dimensional in conventional dermatology consultation and two-dimensional in teledermatology consultation, which take longer to view and check.²⁵

In this study, we consider that a certain way of consultation for a dermatological patient generates an opportunity cost when it uses additional time by the dermatologist that could be used more productively for another activity. Accordingly, the total cost of a dermatological consultation will have to include money for this additional time that is lost when a longer consultation is applied instead of the other type – in this case a teledermatology consultation. This extra time that the professional obtains by not using teledermatology, although it exists, is not necessarily used to see more patients, but it will lead to increased labour productivity – time available for other activities – among the professionals concerned. To calculate this opportunity cost, it is necessary to assign a price to the resources used. As in our case there are no market prices to assess this cost, we have calculated the cost/time factor unit ξ as a way to quantify it. The value of ξ is 3.88 €/min, with which the opportunity cost quantified for each dermatological remote consultation is €29.25. These data show that the time savings for the consultation by using the most time-efficient approach (conventional dermatology consultation) enables the dermatologist to be more productive.

There are no studies in the literature analysing the opportunity cost of the dermatologist’s consultation time with its effectiveness, in terms of clinical outcomes. Nevertheless, there are numerous published articles comparing the two procedures (conventional and teledermatology) which do not observe any significant differences in clinical outcomes. As a result, in our study, and as we were strictly assessing the opportunity cost of the consultation time, we assumed that the effectiveness of the two procedures is the same.^26,27

In our work we have selected articles on two different techniques of teledermatology: real-time video consulting and store and forward. Video consulting teledermatology involves a real-time interaction between two professionals, with the potential for adjustments, finishing touches and sending new images online. The clinical information is consequently complete and the dermatologist’s response is immediate and more decisive, although there is no time-space flexibility for the answer. Store-and-forward teledermatology does not take place in real time and new images must be sent separately; the clinical information provided is standardized and the response of the dermatologist is delayed compared with real-time teledermatology, although this technique provides space-time flexibility in the response. Real-time teledermatology is more expensive than the store-and-forward technique. The educational capacity is better in video consulting.²⁸

While the methodology for calculating the opportunity cost as presented in this work could be extrapolated, this is not the case with the estimated figures, as they are the result of a meta-analysis and may therefore only be part of studies of decision models or of other assessments based on retrospective data. These estimates cannot be adopted in future economic evaluation studies based on RCT clinical trials. Here, in order to calculate the opportunity cost of the time of the dermatologist’s consultation, they have to be obtained from all of the data for the centre evaluated, and from the information that the centre provides. Teledermatology has created an important provision for the future for most public and private health systems, but it is important to analyse the economic aspects. There are few cost-utility and cost-effectiveness studies in the literature; some, but not all^29–31 show that telemedicine reduces costs, and the opportunity cost of the professional dermatologist’s time must also be taken into consideration.

In conclusion, there is no unanimity in the literature regarding which of the two procedures is cheaper, because there are multiple costs involved and they are not always analysed in all the works. Further studies are necessary, with all the standardized variables needed to obtain comparable results in a meta-analysis. In this meta-analysis, teledermatology takes more time than conventional dermatology to implement the diagnostic and therapeutic procedures in the first dermatological visit, and this difference translates financially into an opportunity cost, which increases the total cost of the teledermatological consultation.

Footnotes

Declaration of conflicting interests

The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Funding

The author(s) received no financial support for the research, authorship, and/or publication of this article.

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