This is an open-access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work, first published in the Journal of Medical Internet Research, is properly cited. The complete bibliographic information, a link to the original publication on http://www.jmir.org/, as well as this copyright and license information must be included.
Internet interventions with and without therapist support have been found to be effective treatment options for harmful alcohol users. Internet-based therapy (IT) leads to larger and longer-lasting positive effects than Internet-based self-help (IS), but it is also more costly to provide.
To evaluate the cost effectiveness and cost utility of Internet-based interventions for harmful use of alcohol through the assessment of the incremental cost effectiveness of IT compared with IS.
This study was performed in a substance abuse treatment center in Amsterdam, the Netherlands. We collected data over the years 2008–2009. A total of 136 participants were included, 70 (51%) were female, and mean age was 41.5 (SD 9.83) years. Reported alcohol consumption and Alcohol Use Disorders Identification Test (AUDIT) scores indicated harmful drinking behavior at baseline. We collected self-reported outcome data prospectively at baseline and 6 months after randomization. Cost data were extracted from the treatment center’s cost records, and sex- and age-specific mean productivity cost data for the Netherlands.
The median incremental cost-effectiveness ratio was estimated at €3683 per additional treatment responder and €14,710 per quality-adjusted life-year (QALY) gained. At a willingness to pay €20,000 for 1 additional QALY, IT had a 60% likelihood of being more cost effective than IS. Sensitivity analyses attested to the robustness of the findings.
IT offers better value for money than IS and might therefore be considered as a treatment option, either as first-line treatment in a matched-care approach or as a second-line treatment in the context of a stepped-care approach.
Netherlands Trial Register NTR-TC1155; http://www.trialregister.nl/trialreg/admin/rctview.asp?TC=1155 (Archived by WebCite at http://www.webcitation.org/6AqnV4eTU)
Harmful alcohol use is the number-3 leading contributor to global burden of disease [
We collected data for the cost effectiveness analysis alongside a pragmatic randomized controlled trial on the effectiveness of IT relative to IS and a waiting list, conducted in the Netherlands in 2008–2009. Because in economic evaluation the preferred comparison is between the intervention of interest (IT) and its best alternative, in this case IS, we do not present waiting list data in this paper.
We recruited applicants through jellinek.nl, a substance abuse treatment center website with 650,000 visitors annually [
Both IT and IS were based on a cognitive behavioral therapy and motivational interviewing treatment protocol [
In this economic evaluation, we used the societal perspective. All costs related to IT and IS interventions, health care uptake, opportunity costs of the participant’s time, and productivity losses were included. All costs (
CONSORT trial flow diagram for the randomized controlled trial. AUDIT = Alcohol Use Disorders Identification Test, ITT = intention-to-treat analysis, IS = Internet-based self-help, IT = Internet-based therapy.
Unit costs and average quantities per participant for Internet-based therapy and Internet-based self-help.
Cost type | Unit | Internet therapy | Internet self-help | ||||
No. of |
€/unit | No. of |
€/unit | ||||
|
|||||||
Therapist therapy | Hour | 2.49 | 79.20 | NAa | NA | ||
Therapist administration | Hour | 0.55 | 79.20 | NA | NA | ||
Software development | Participant | 1 | 23.25 | 1 | 4.87 | ||
ICTb service | Participant | 1 | 14.92 | 1 | 2.49 | ||
Software overhead | Participant | 1 | 4.27 | 1 | 4.27 | ||
Total intervention costs | Participant | 1 | 283.21c | 1 | 11.63c | ||
Participant’s leisure time | Hour | 10.33 | 9.18 | 2.43 | 9.18 | ||
Work absenteeismd | Hour | 32.12 | 22.21–52.91e | 18.35 | 22.21–52.91e | ||
Work presenteeismf | Hour | 8.15 | 22.21–52.91e | 12.15 | 22.21–52.91e |
a Not applicable.
b Information and computer technology.
c Average intervention cost per participant. Individual costs varied and depended on the amount of intervention uptake.
d Average number of work hours lost in the 6 months preceding measurement due to participants not going to work (eg, sick leave).
e Range of unit cost. The unit value was dependent on sex and age of the participant and based on 2010 Harmonized Index of Consumer Prices inflation-corrected average hourly wages [
f Average number of work hours lost in the 6 months preceding measurement due to participants not functioning well professionally while at work.
IT and IS intervention costs consisted of software development costs, information and computer technology service costs, overhead costs (based on the treatment center’s cost records), and—for IT only—therapist-related costs. We collected the cost data over the years 2004-2009. Information and computer technology service costs were based on averaged annual costs and included server rental costs, software security costs, and a monthly information and computer technology support fee. Overhead costs were based on actual time investment estimations. Time invested was multiplied by labor costs based on collective labor agreement wages, with 50% additional employer costs for overhead and insurance. Development, information and computer technology service, and overhead costs were divided by the monthly recorded number of participants (IT: 25; IS: 50). Therapist costs were based on the actual chat-contact time, with an added 10 minutes per chat session for supervision and administrative work. Therapist work time was valued based on average sex-, age-, and profession-specific labor costs in the Netherlands [
We restricted participant costs to a valuation of their time investment, valued as leisure time at €9.18 per hour [
Additional societal costs were calculated using a macroscopic approach based on global burden of disease and injury data [
The central clinical outcome for the cost effectiveness analysis was treatment response, based on alcohol consumption during the last 7 days. In the study protocol we defined treatment response as alcohol consumption within the British Medical Association boundaries (no more than 14 standard units for women, or 21 units for men, per week) [
The central outcome for the cost utility analysis was the number of quality-adjusted life-years (QALYs) as calculated with the 5-dimensional EuroQol (EQ-5D) [
We carried out all analyses on an intention-to-treat basis. Missing observations in costs and effects data were handled using multiple imputation. The multiple imputation software package Amelia II [
We analyzed cost and effect data according to methods suggested by Drummond and colleagues [
Baseline characteristics of participants in Internet-based therapy (IT) and Internet-based self-help (IS).
Characteristic | IT (n = 68) | IS (n = 68) |
|
|
||
Women, n (%) | 35 (51%) | 35 (51%) | 0.00 | 1.00 | ||
Age (years), mean (SD) | 41.9 (10.1) | 41.1 (9.6) | 0.49 | .63 | ||
|
4.49 | .10 | ||||
Low | 2 (3%) | 7 (11%) | ||||
Medium | 24 (38%) | 30 (46%) | ||||
High | 38 (59%) | 29 (44%) | ||||
Employed, n (%) | 58 (85%) | 55 (82%) | 0.25 | .65 | ||
|
0.74 | .75 | ||||
Low | 9 (13%) | 6 (9%) | ||||
Medium | 21 (31%) | 22 (32%) | ||||
High | 37 (55%) | 40 (59%) | ||||
AUDITb composite score, mean (SD) | 18.8 (4.8) | 19.6 (5.6) | 0.98 | .33 | ||
Duration of alcohol problems (years), mean (SD) | 5.2 (5.7) | 5.4 (5.7) | 0.23 | .82 | ||
Drinks per week, mean (SD) | 45.2 (26.3) | 43.4 (24.0) | 0.38 | .71 | ||
EQ-5Dc score | 0.79 (0.20) | 0.80 (0.18) | 0.32 | .75 | ||
Work absenteeismd | 756 (2289) | 1863 (6983) | 1.24 | .22 | ||
Work presenteeismd | 1137 (2386) | 794 (1922) | 0.78 | .44 |
a Classified according to Statistics Netherlands (CBS) and International Standard Classification of Education 1997.
b Alcohol Use Disorders Identification Test [
c 5-dimensional EuroQol instrument, score calculated using the measurement and valuation of health (MVH-A1) algorithm from Dolan [
d Averaged costs over the 6 months preceding baseline measurement.
We extracted 1000 nonparametric bootstrapped [
The resulting 1000 ICERs per dataset were used for further calculations and plotted on the cost effectiveness plane [
Cost effectiveness plane (left) and cost effectiveness acceptability curve (right) with treatment response as the effect measure.
Based on the distribution of the ICERs over the cost effectiveness plane, cost effectiveness acceptability curves [
Cost effectiveness plane (left) and cost effectiveness acceptability curve (right) with quality-adjusted life-year (QALY) as the effect measure.
To test the robustness of the economic evaluation, we performed a sensitivity analysis in which we varied the most relevant cost drivers. First, the cost effectiveness analysis was replicated from the health care provider perspective, including only health care costs in the analysis. In other alternative scenarios, the influence of the most influential cost drivers (ie, intervention costs and productivity costs) was explored. These costs drivers were raised and lowered independent of each other, in order to test the influence of adjustments on the median ICER and the likelihood that IT is more cost effective than IS.
Of the 136 participants included in this cost effectiveness analysis, 68 were randomly assigned to IT and 68 to IS. The participants (n = 70, 51% women) were a mean of 41.5 (SD 9.83) years old (
Per-participant costs in IT and IS, and bootstrapped incremental costs are presented in
Costs and increments in the 6-month period preceding follow-up of the Internet-based therapy (IT) and Internet-based self-help (IS) groupsa.
Cost type | IT | IS | Bootstrapped difference | ||||
Mean | SD | Mean | SD | Median | 95% CIb | ||
|
|||||||
Therapist labor | 241 | 236 | 0 | 0 | 240 | 187–296 | |
Software development | 23 | 0 | 5 | 0 | 18 | 18–18 | |
Software/hardware service | 15 | 0 | 2 | 0 | 12 | 12–12 | |
Software overhead | 4 | 0 | 4 | 0 | 0 | 0–0 | |
Total intervention costs | 283 | 236 | 12 | 0 | 271 | 217–327 | |
Participant time investment costs | 95 | 103 | 22 | 37 | 72 | 48–99 | |
|
|||||||
Work absenteeism | 1114 | 5704 | 536 | 3800 | 555 | –967 to 2234 | |
Work presenteeism | 217 | 847 | 350 | 1637 | –119 | –609 to 256 | |
Total productivity costs | 1331 | 5774 | 886 | 4215 | 417 | –1215 to 2208 | |
|
|||||||
Additional societal costsc | 301 | 1305 | 200 | 953 | 94 | –275 to 499 | |
Total societal costs | 2010 | 7141 | 1120 | 5167 | 845 | –1157 to 3048 | |
Treatment response (proportion) | 0.53 | 0.29 | 0.24 | 0.07–0.38 | |||
EQ-5Dd score | 0.89 | 0.20 | 0.78 | 0.34 | 0.12 | 0.05–0.18 | |
ICERe treatment response | 3683 | –5703 to 20,366 | |||||
ICER QALYf | 14,710 | –18,337 to 71,664 |
a All costs have been rounded for presentation in this table, and may therefore not add up exactly.
b Confidence interval.
c An estimation of real costs, based on Rehm et al [
d 5-dimensional EuroQol instrument, score calculated using the measurement and valuation of health (MVH-A1) algorithm from Dolan [
e Incremental cost effectiveness ratio.
f Quality-adjusted life-year.
By dividing the incremental costs by the incremental effects, the mean ICER of IT compared with IS from the societal perspective is calculated as €845/0.24 = €3521 for 1 additional treatment responder, 6 months after inclusion. Using the bootstrapping procedure, we estimated the median ICER to be €3683. In the cost effectiveness plane (
The mean incremental societal costs for 1 additional QALY gained by IT compared with IS were €845 / 0.06 = €14,083. The median ICER for 1 extra QALY was estimated too be €14,710. From
In
Cost effectiveness acceptability curve after sensitivity analyses with treatment response (left) and quality-adjusted life-year (QALY) (right) as effect measures.
Cost effectiveness analysis of base case, health care provider perspective, and additional sensitivity analyses.
Cost drivers | Base |
Alternative |
Sensitivity analyses | ||||||
Ia –40% | I +40% | Pb –40% | P +40% | I and P |
I and P |
||||
Incremental costs (median) | 845 | 271 | 739 | 954 | 681 | 1012 | 573 | 1120 | |
|
|||||||||
Incremental effects (median) | 0.24 | 0.24 | 0.24 | 0.24 | 0.24 | 0.24 | 0.24 | 0.24 | |
ICERc (median) | 3683 | 1157 | 3187 | 4172 | 2977 | 4387 | 2494 | 4868 | |
ICER (95%low) | –5703 | 665 | –6441 | –5050 | –3227 | –8313 | –3821 | –7576 | |
ICER (95%high) | 20,366 | 3722 | 19,410 | 21,409 | 14,724 | 25,979 | 13,738 | 26,957 | |
WTPd €4000 | 53% | 95% | 57% | 50% | 62% | 48% | 66% | 46% | |
WTP €8000 | 76% | 98% | 78% | 74% | 85% | 69% | 87% | 67% | |
WTP €12,000 | 87% | 99% | 89% | 86% | 92% | 82% | 93% | 80% | |
Upper right quadrant | 79% | 99% | 76% | 82% | 83% | 76% | 79% | 79% | |
Upper left (inferior) quadrant | 1% | 1% | 1% | 1% | 1% | 1% | 1% | 1% | |
Lower left quadrant | 0% | 0% | 0% | 0% | 0% | 0% | 0% | 0% | |
Lower right (dominant) quadrant | 20% | 0% | 23% | 17% | 16% | 22% | 20% | 20% | |
|
|||||||||
Incremental QALYs (median) | 0.06 | 0.06 | 0.06 | 0.06 | 0.06 | 0.06 | 0.06 | 0.06 | |
ICER QALY (median) | 14,710 | 4693 | 12,932 | 16,584 | 11,876 | 17,683 | 9946 | 19,436 | |
ICER QALY (95%low) | –18,337 | 2783 | –20,177 | –16,241 | –10,291 | –26,220 | –12,282 | –24,352 | |
ICER QALY (95%high) | 71,664 | 10,848 | 67,913 | 75,671 | 52,202 | 91,101 | 48,403 | 94,958 | |
WTP €10,000 | 40% | 95% | 45% | 36% | 44% | 38% | 50% | 35% | |
WTP €20,000 | 60% | 99% | 64% | 57% | 70% | 54% | 74% | 51% | |
WTP €40,000 | 85% | 100% | 87% | 83% | 93% | 77% | 94% | 74% | |
Upper right quadrant | 80% | 100% | 76% | 83% | 84% | 77% | 80% | 80% | |
Upper left (inferior) quadrant | 0% | 0% | 0% | 0% | 0% | 0% | 0% | 0% | |
Lower left quadrant | 0% | 0% | 0% | 0% | 0% | 0% | 0% | 0% | |
Lower right (dominant) quadrant | 20% | 0% | 23% | 17% | 16% | 23% | 20% | 20% |
a Intervention costs.
b Productivity costs.
c Incremental cost effectiveness ratio.
d Willingness to pay.
e Quality-adjusted life-year.
In this cost effectiveness analysis, we found that the IT intervention led to almost double (0.53 versus 0.29) the number of treatment responders at 6 months, which was achieved at an incremental cost of €845 (equivalent to US $1008, based on purchasing power parity for the reference year 2010 [
The maximum WTP per QALY is a matter of debate, but the figure of €20,000 is conservative compared with the World Health Organization’s recommendation of a maximum cost per QALY of 3 times the gross domestic product per capita (€88,000 for the Netherlands in 2010) [
It is clear that the costs of providing IS from a health care provider perspective are only a fraction of those of providing IT. Alternatively, a stepped-care approach could be proposed, in which a client is referred to IS first and then is referred to IT in a second step when desirable results have not been achieved after IS.
Smit and colleagues [
A limitation of this study stems from the generalizability of the cost data. The reported software costs were based on actual cost records, which may be different in other settings. To estimate full societal costs, we measured productivity loss cost data using the SF-HLQ, but we estimated health care costs other than the focal intervention and for law enforcement based on Rehm and colleagues [
We collected data on productivity losses using the SF-HLQ, aiming at a 2-week period before data collection. Subsequently, we extrapolated the calculated costs of productivity losses. An alternative approach to calculating absence days could have been applied by (1) retrospectively asking participants about their work absenteeism in the previous 3 or 6 months, and thus collecting an alternative measure of absenteeism based on which we could have validated our extrapolation approach, or (2) measuring absenteeism, presenteeism, and the main clinical end points more frequently, in order to have more data on which to base the extrapolation. This would, however, have increased the research burden on our study participants, but it would presumably also have led to more sound data on costs (and effects). To assess the robustness of the results in terms of deviations from the calculated costs, we performed sensitivity analyses, plus an additional analysis in which we took into account only the intervention costs (health care provider cost perspective).
Another limitation was the time horizon in this analysis, which was restricted to 6 months. It is very possible that clinical effects were maintained after 6 months, although they may diminish over time. The same may be true for losses or gains in (productivity) costs. We have, however, not modeled the possible developments of effects and costs beyond the 6 months for which we have empirical data. This limits the time horizon and may jeopardize informed decision making when considering long-term effects.
By collecting patient-level cost data alongside a pragmatic randomized controlled trial, this study has both good comparability of the populations in the two interventions as a consequence of random allocation, and acceptable external validity as a result of the pragmatic approach [
Alcohol Use Disorders Identification Test
5-dimensional EuroQol
incremental costeffectiveness ratio
Internet-based self-help
Internet-based therapy
quality-adjusted life-year
Short Form-Health and Labor Questionnaire
willingness to pay
The randomized trial and the cost effectiveness analysis reported in this paper were funded by Grant #31160006 from the Netherlands ZonMw Addiction II Program (Risk Behavior and Dependency). The study was conducted in collaboration with the Jellinek Clinic, which is a division of Arkin, the Amsterdam-based mental health and addiction treatment center. Arkin supported the trial and facilitated its development. The two interventions evaluated in this study were developed at Jellinek. None of the funders of the project had any role in the design of the trial, selection of the measurement instruments, or preparation of the manuscript. The protocol of this randomized controlled trial has been published previous to the trial’s execution. The trial was conducted in agreement with the Declaration of Helsinki and was approved by the Medical Ethics Committee of the Academic Medical Centre of the University of Amsterdam, the Netherlands. Publication of this paper was financially supported by grant #036.001.899 from the Netherlands Organization for Scientific Research (NWO) – Incentive Fund Open Access.
None declared.