Abstract
Summary
Web-based interventions offer potential benefits for managing and treating depression in the context of chronic physical illness, however their use with this population has yet to be quantitatively assessed. The present systematic review examined the biopsychosocial data from 11 independent studies (N = 1348 participants), including randomised controlled and quasi-experimental designs most commonly performed with diabetes and multiple sclerosis. Study quality was evaluated using the Downs and Black (1998) index, with most studies being statistically underpowered although internal validity was demonstrated. Treatment outcomes were quantified using Cohen’s d effect sizes. Results indicated significant short-term improvements in depression severity (dw = 0.36, CI = 0.20-0.52, p < 0.01), in addition to quality of life, problem-solving skills, functional ability, anxiety and pain-related cognitions (d range = 0.23 to 1.10). Longer-term outcomes could not be determined based on the limited data. Further robust studies are required before wider adoption of web techniques takes place.
Targeted depression treatment constitutes a critical component of chronic illness management, with up to 50% of adults diagnosed with cancer, diabetes mellitus, heart disease, rheumatoid arthritis or stroke experiencing a moderate to severe range of cognitive and behavioural symptoms consistent with Major Depressive Disorder.1,2 However, barriers to accessing psychological treatments have been identified. This includes knowledge and beliefs (i.e. stigma) about mental disorders, illness symptoms (e.g. neuropathic pain) which impede therapy engagement, in addition to service access issues for those who are geographically remote.3–4 In this context, web-based psychological interventions offer an efficient and accessible means of service delivery.5,6
Meta-analytic and systematic reviews of web-based psychotherapies for the general population have demonstrated treatment efficacy. Computerized cognitive behaviour therapy (CBT), in particular, has been found to contribute to moderate improvements in depressive symptomatology in addition to comparability with face-to face psychotherapy.7–13 Interactive and self-guided web interventions in chronic illness settings have also demonstrated psychosocial benefits, including improved quality of life.14–16 However, available reviews have focused on medical outcomes 14 or have included a broad range of psychosocial interventions as opposed to targeted treatment of depression.15–16 As individuals with comorbid depression and chronic illness are at a high risk of mortality, morbidity and increased healthcare costs, a specific focus on this patient group is warranted.1,2
The present quantitative review provides an initial examination of targeted web-based interventions for depression among chronic illness groups. Specific aims are to: 1) examine the methodological quality of the available empirical literature; 2) quantify the short- and longer-term biopsychosocial effects of web-based interventions; and 3) identify treatment factors that impact on consumer acceptability and satisfaction.
Methods
Inclusion and exclusion criteria
This review is registered with PROSPERO (registration CRD42014013938). Eligible studies had to be published in English in a peer-reviewed journal from 1990 (coinciding with introduction of worldwide web in 1991) until 2014. 17
Participants
Studies had to target adult participants (aged 18 years or older) with a primary diagnosis of chronic illness and comorbid depression. Chronic illness was defined as a physical health problem that involves a complex causality, long latency, prolonged and often progressive course with resulting functional impairment.1,4,18 This included non-communicable diseases (e.g., cancer, cardiovascular disease), communicable diseases (e.g., HIV/AIDS), and impairments in body structure (e.g., joint disorders). Studies with participants in cancer remission and those at risk of developing cardiovascular disease were also eligible, as they have been previously considered sufficiently homogenous.19,20 Depression was defined in accordance with diagnostic criteria (Diagnostic and Statistical Manual of Psychiatric Disorders version III-R and later, International Classification of Disease version 9 and later),21,22 or depressive symptomatology (i.e. above a predefined cut-off on a validated self-report or clinician measure).
Web-based interventions
The examined web-based interventions required the following components: (a) program content (i.e. psychoeducation and skills training, guided by psychological theory); (b) multimedia use/choices; (c) provision of interactive web-based activities; and d) provision of guidance and supportive feedback, either through inbuilt program content (i.e. self-guided programs), or via human assistance. 23 Eligible interventions had to target depression symptomatology, with the specific intent of producing emotional, behavioural, and cognitive change. 23
Study design
Intervention studies with a repeated measures design, including randomised controlled trials and quasi experimental studies, were eligible. Quasi experimental designs help to minimise some of the practical and ethical difficulties in implementing a no-treatment control condition within a clinical setting and are considered advantageous in terms of their high external validity. 24
Search strategy
The Pubmed, PsycINFO, Scopus, and Embase databases were searched using logic grids developed with the assistance of a research librarian (see online supplementary material). The following topic-specific journals were also searched: Journal of Telemedicine and Telecare; Telemedicine and e-health; Cyberpsychology and Behaviour; Cyberpsychology, Behavior, and Social Networking; International Journal of Medical Informatics; Electronic Journal of Health Informatics; Journal of the International Society for Telemedicine and eHealth; Journal of Technology in Human Services. Additional studies were located from the reference lists of identified studies. The database search was conducted by the first author (E.C), with results confirmed by the second and third authors (D.D, P.M) to minimize potential selection bias.
25
After applying the aforementioned criteria, eleven articles were deemed eligible for inclusion in this review (Figure 1).19,26–35
Flowchart of article selection.
Data extraction
Consistent with the PRISMA guidelines 36 the following data were extracted from each study: research design (e.g. randomised vs quasi-experimental, independent versus dependent groups design); sample characteristics (e.g. sample N, medical diagnosis, mean age, time since diagnosis); and treatment characteristics (e.g. session frequency, duration). Where available, statistics necessary for calculating treatment effects (i.e. means and standard deviations) were also extracted, with two studies26,27 providing additional data on request. Data extraction was conducted by the first author (E.C).
Quality evaluation
The 27-item Quality Index (QI) 37 was utilised to identify methodological bias (i.e. study power, reporting quality, external and internal validity). Each item is scored as 0 (not present) or 1 (present), with item scores totalled. Additional points are allocated for adequate power calculations and detail relating to potential confounders in the selection of study participants, resulting in a maximum quality score of 32. The QI has demonstrated inter-rater reliability (r = 0.75). 37 Quality ratings were independently undertaken by the first and second authors (E.C., D.D.), with good inter-rater consistency demonstrated (Spearman’s rho = 0.87, p < 0.01 38 ). Consensus quality scores were subsequently achieved through discussion (see online supplementary material).
Effect size estimation
Cohen’s d effect sizes39,40 were calculated to quantify treatment outcomes for ten studies, with Thompson et al 34 providing binary data. As per Cohen’s 39 criteria, d values of 0.2, 0.5, and 0.8 indicated small, medium, and large treatment effects.
The computation of d involved several stages. First, effect sizes were calculated for each individual outcome measure utilised by a study. Where available, intention-to-treat (ITT) data were utilised as recommended for psychotherapy research. 41 Second, the direction of d was standardised so that a positive value indicated that the web-based intervention was beneficial. Third, 95% confidence intervals (CI) were calculated for all effect sizes, with CIs that do not include the value of zero considered clinically significant. 42 Effect sizes for the primary outcome, depression, were separately examined using the I2 heterogeneity index (random effects model). 43 This involved pooling and weighting the individual d’s for each study by their inverse variance. Cooper et al 26 utilised two self-report measures of depression, which were averaged for the I2 analysis in order to ensure data independence. 42 I2 is expressed as a percentage, with values < 40% representing an appropriate level of methodological and clinical variability. 43 Finally, publication bias was addressed by calculating fail-safe N (Nfs). 42 The Nfs statistic estimates the number of unpublished studies with non-significant results (d = 0.20) 44 which would be required to exist in order to overturn the findings. Larger Nfs values indicate a greater likelihood that such studies are unlikely to exist.
Results
Participant characteristics
Summary of included studies (N = 11 studies).
Measure abbreviations: BDI-II: Beck Depression Inventory II; HADS: Hospital Anxiety Depression Scale; K-10: Kessler Psychological Distress Scale; CES-D: Center for Epidemiological Studies Depression Scale; PHQ9: Patient Health Questionnaire; MSIS-29: Multiple Sclerosis Impact Scale; mBDI: Beck Depression Inventory (modified).
(-) indicates data not provided or available.
Intervention characteristics
Five web-based interventions had been designed to manage depression symptoms in the general population,19,26,27,31,33 with the remaining studies modified to incorporate illness-specific information and clinical examples. Most treatments involved an individual format, with only two group interventions evaluated.29,34 Interventions were time-limited, with treatment involving an average of nine modules (SD = 4, range = 5 to 16) delivered on a weekly or biweekly basis over 1 to 6 months (median = 8 weeks). CBT was the primary framework, with four studies utilising registered or trainee psychologists to promote completion of session material and homework tasks.28,32,33,35 Additional online resources included a bulletin board, peer-led discussion forum and instructional videos.
Study quality
Quality scores ranged from 14 to 29 out of a maximum 32 (mean = 19, SD = 4.6; see online supplementary material). Aside from three studies,30,33,35 most were underpowered due to the use of small sample sizes. Reporting quality was adequate with key hypotheses, outcome measures and findings described in addition to protocols for addressing potential suicide risks. Five studies26,27,28,33,35 discussed the characteristics of participants who withdrew and the consequent socio-demographic disparities between completers and non-completers, however recruitment difficulties and limited detail relating to the source population contributed to poor external validity. Internal validity was achieved through the use of random allocation to treatment conditions (N = 10 studies), although the method of randomization was not always clearly described.
Treatment effectiveness
The nine studies providing depression outcome data contributed to a positive and medium dw (Figure 2). A more conservative treatment effect was noted when randomised controlled trials were examined only (dw = 0.31; CI = 0.17 to 0.45; p < 0.01). Although appropriate heterogeneity was demonstrated (I2 = 19.73%, CI = 0.00–71.74%), the associated CI suggests a wide spectrum of possible degrees of heterogeneity (i.e. mild to substantial).
Forest plot of short-term depression outcomes.
Improvements in depression symptomatology were noted by individuals with multiple sclerosis who completed web-based problem-solving therapy 28 or CBT. 26 Individuals with chronic arthritic pain also reported treatment gains following web-based CBT supplemented with therapist contact via telephone, moreso than peers who accessed usual care. 32 Controlled comparative outcome studies were limited, although web-based CBT produced greater treatment effects than a health information package for individuals with high cardiovascular risk. 33 These findings are consistent with the proportional data provided by Thompson et al, 34 with mean Beck Depression Inventory (BDI) scores decreasing by 59% among adults with epilepsy who accessed a mindfulness-based cognitive program compared to waitlist controls (15% reduction in pre- to post- BDI), and no statistically significant differences noted between web- and telephone-delivered programs. These results need to be interpreted cautiously given the sparse dataset.
Short-term treatment effects for standardised measures administered pre- and immediately post-intervention.
Abbreviations: d: Cohen's effect size; CI: 95% confidence interval; T vs C: treatment vs. wait list or usual care; T vs T: treatment vs comparative online condition; Treatment: single group (treatment only); Completers: d calculated on treatment completers; ITT: d calculated on intention-to-treat data. *significant treatment effect: CI ≠ 0.
Four controlled studies provided 1 to 3 month follow-up data, contributing to a pooled and non-significant d (Figure 3).26,27,32,35 Depressed patients in van Bastelaar’s evaluation of web-based CBT
35
reported a small, albeit significant improvement (d = 0.29, CI = 0.17 -0.40) in diabetes- specific distress in comparison to waitlist controls (Figure 3). Descriptive data provided by Thompson et al
34
also indicated a persistent reduction in depression symptoms at 8 weeks post-treatment, although the authors acknowledge that their results were preliminary (N = 13). Additional psychosocial outcomes were not maintained following the cessation of treatment (Table 3).
Forest plot of follow-up depression outcomes. Longer-term treatment effects for standardised measures administered at follow-up. Abbreviations: d: Cohen's effect size; CI: 95% confidence interval; T vs C: treatment vs. wait list or usual care; Treatment: single group (treatment only); Completers: d calculated on treatment completers; ITT: d calculated on intention-to-treat data.
Treatment adherence and satisfaction
Treatment completion rates varied from 30% to 93%, with Dear et al 32 enhancing recruitment by utilising public advertisements in local newsletters or newspapers and online media. Cited reasons for dropout included technological difficulties, socio-environmental stressors (e.g. job redundancy, relationship difficulties), illness-related problems and conflicting time commitments.26,28 A higher completion rate was found among diabetic participants recruited online in comparison to in-person recruitments from a community clinic, 31 whilst van Bastelaar and colleagues 35 noted anxiety disorders to be prevalent among non-completers. Treatment adherence was formally evaluated by two studies. Duffecy and colleagues 19 reported a trend-level significance for a larger number of website log-ins among treatment participants, whereas Cohn et al. 31 suggested that the time commitment required by their coping skills intervention (e.g. structured exercises, homework) may have contributed to reduced log-ins. Participants valued the inclusion of therapist support, psycho-education with illness-specific examples, structured therapy framework and opportunity for peer discussion. Negative feedback was noted by one study – with the BDI identified as an inaccurate reflection of individuals’ affective experience with multiple sclerosis. 26
Discussion
This review consolidates the findings from 11 studies investigating the effectiveness of web-based interventions for comorbid depression in populations with chronic illness. Although immediate improvements in depression symptom severity and broader psychosocial outcomes were identified, longer-term treatment effects could not be established. These findings need to be considered in the context of study quality, with limited information on randomization strategies and treatment blinding – qualities that are considered cornerstones of treatment evaluation. 45
These results are consistent with previous research supporting the short-term efficacy of web-based depression treatments in the general population,7,8,11,13 lending support to the notion that web-based interventions have potential as a psychology service delivery option for chronic illness groups. The broader effects of the web-based interventions on perceived frequency and quality of social support networks, self-efficacy and anxiety, are also important for individuals with a chronic health condition due to the high comorbidity with psychosocial detriments, contributing to lowered quality of life.1,2 It follows that modifying these psychosocial factors, which may themselves predispose or enable improved health care utilization, can contribute to improved self-management and participation in web-based psychological services.46–48
The relationship between depression outcomes and degree of therapist involvement requires further evaluation, with few studies providing direct comparisons (e.g. clinician vs self-guided intervention). Cooper et al’s 26 self-management program reported the largest treatment gain, however this finding was based on less than 30 participants, precluding generalizability of the data. The broader web-based intervention literature favours supported intervention over self-guided help, although there are some exceptions to this.15,16,51,52 Further research is therefore needed to clarify the components of effective self-guided interventions, including the availability of technological support in maintaining participant engagement.49,50 Similarly, the need for illness-specific modifications in depression treatments 3 was not clearly reflected in the findings of this review.
Practical considerations surrounding recruitment and retention were highlighted, with illness-related issues and time demands cited as key reasons for attrition.10,53 It may also be that the delivery of psychological services in a technological environment introduces a selection bias – potentially excluding those sub-groups with reduced web literacy such as the elderly and those from disadvantaged socio-economic backgrounds. 54
Study evaluation identified the need to consider alternative research designs, with the ‘gold standard’ randomised controlled trial and double blinding difficult to achieve within a psychotherapeutic setting. 45 This might include the case series design, which focuses on individual treatment change over time, 55 alongside qualitative research to determine aspects such as patient acceptability. Generalisability of the current findings can also be improved in future web-based psychotherapy research by providing a clear description of sample and study characteristics, including demographic details of completers and non-completers and potential treatment confounders.37,56 This might include the type and extent of one’s prior engagement with psychotherapeutic services and current psychotropic management. Adherence rates were also not consistently measured or documented across available studies, making it difficult to understand the level of engagement with the examined interventions, and therefore validity of outcomes. Donkin and colleagues 57 suggest the use of a composite measure encompassing activity completion, time spent online, and active engagement with the treatment material as a best measure of adherence. It would also be advantageous for future research to utilise common validated measures in order to allow data pooling. Although this is challenging given variation in the prevalence of depression and other physical, cognitive and psychosocial outcomes inherent in the chronic illness population, 58 tools such as the depression metric of the National Institutes of Health (NIH) Patient-Reported Outcomes Measurement Information System (PROMIS) 59 have demonstrated reliability with medical populations. The PROMIS, in particular, maps onto scores from existing depression measures (e.g. BDI), allowing for ease of comparison. 60
Limitations
Caution is needed in drawing conclusions from this review. In particular, measurement issues can be substantial when making between-study comparisons among a small number of trials. This includes differences in the scaling and precision of measurement across the 26 outcome measures utilised by the identified studies, despite some focussing on the same psychosocial concept. 61 These measurement problems are partly overcome by using standardised estimates of effect magnitude, such as Cohen’s d, although d estimates based on single-group designs may be inflated. 41 In addition, sample differences in depression criteria (i.e. different cut-off scores at which depression is considered clinically meaningful) which are also likely to vary according to the characteristics of a chronic illness group,1,2 may influence the sensitivity and specificity of a depression measure resulting in over- or underestimation of treatment effects.62,63 Finally, the current findings may be undermined by publication bias, with a tendency for academic journals to publish significant findings. 64 The calculated fail safe Ns acknowledge this issue but can also underestimate the extent of bias. 65
Conclusions
This is the first review to systematically and quantitatively examine the impact of targeted web-based interventions on depression outcomes in populations with chronic illness. The initial indication of moderate to large reductions in depression symptomatology is promising. Further controlled research is required to confirm web interventions as an evidence-based practice, including optimal treatment format, frequency and duration.
Footnotes
Acknowledgements
The authors would like to acknowledge the assistance of Research Librarian M. Bell, University of Adelaide, with the database searches. Thanks must also go to the authors of included studies for providing further details on request.
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) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: EC is supported by a Nursing and Allied Health Scholarship and Support Scheme Clinical Psychology Scholarship. PJT is supported by the National Health and Medical Research Council of Australia (Neil Hamilton Fairley —Clinical Overseas Fellowship #1053578).
