|Exposure-in-vivo containing interventions to improve work functioning of workers with anxiety disorder: a systematic review
|Noordik E, van der Klink JJ, Klingen EF, Nieuwenhuijsen K, van Dijk FJ
The review found that treatments for anxiety that included exposure-in-vivo can reduce work-related problems in workers with obsessive-compulsive disorder or post-traumatic stress disorder more effectively than other anxiety treatments or a waiting list. These conclusions require cautious interpretation due to limitations in the review, particularly the paucity of data and a lack of information about whether participants truly represented workers.
To assess the effectiveness of interventions containing exposure-in-vivo to improve work functioning in workers with anxiety disorders.
MEDLINE, CINAHL, EMBASE and PsycINFO were searched from inception to 2007. Search terms were reported. Reference lists of reviews and eligible studies were checked and authors of all included studies were contacted seeking further studies.
Randomised controlled trials (RCTs) and non-randomised controlled trials (non-RCTs) of exposure-in vivo for adults (aged 18 to 65 years) with anxiety were eligible for inclusion. Exposure-in-vivo was a required central component of therapy and had to be performed gradually. Eligible control conditions were interventions aimed at reducing anxiety, such as anxiolytic or antidepressant medication, cognitive-behavioural psychotherapy without exposure, waiting list treatment, imaginal or interoceptive exposure, placebo and care as usual. Studies were required to report one or more outcomes related to work functioning.
Participants in the included studies were aged from 15 to 80 years and had obsessive-compulsive disorder, severe phobia or post-traumatic stress disorder (PTSD). Duration of disorder ranged from eight to 22 years, where reported. Most studies did not report the proportion of participants who were working, but where reported this ranged from zero to 58%. Intervention groups received exposure-in-vivo as part of a treatment programme with or without concurrent medication, response prevention and cognitive restructuring. Control conditions included medication, self-relaxation, response prevention, anti-exposure homework, marital therapy, imaginal exposure and waiting list. The number and frequency of treatment sessions varied widely. One study reported employment status; work-related outcomes in all the other studies were measured by questionnaire sub-scales. The review also reported anxiety-related outcomes, measured in most cases by symptom questionnaires. Follow-up ranged from eight weeks to 12 months. Studies were conducted in in-patient, outpatient or academic/community settings in USA, UK and Austria.
Three reviewers performed initial study selection. Two reviewers independently screened the full-text articles. Disagreements were resolved by consensus or by discussion with the third reviewer.
Assessment of study quality
Study validity was assessed with reference to GRADE criteria. Areas assessed included sequence generation, allocation concealment, blinding, completeness of outcome data, selective reporting and other sources of bias.
Two reviewers independently assessed study validity.
For continuous data, post-treatment outcome scores were extracted and standardised mean differences (SMDs, Hedges g) between the groups were calculated, with 95% confidence intervals (CIs). Odds ratios (ORs) with 95% CIs were calculated for dichotomous data. Where studies had two experimental groups, control group sample size was halved to avoid double counting. Where multiple anxiety outcomes were reported for a single group, the effects were summarised by calculating the sum of positive, negative and neutral outcomes.
Two reviewers independently extracted data. Disagreements were resolved by consensus. Primary study authors of more recently published studies were contacted for more data.
Methods of synthesis
Where studies were clinically homogeneous, they were combined to calculate pooled SMDs with 95% CIs. Heterogeneity was assessed using the I2 statistic. Fixed effect-models were used unless there was significant heterogeneity, in which case random-effects models were used. Other data were combined in a narrative synthesis organised by type of disorder.
Results of the review
Seven studies were included (691 participants, range 11 to 218): four RCTs (424 participants) and three non-RCTs (267 participants). Risk of bias was low in two studies, unclear in three and high in two. Four studies used blinded outcomes assessment. Five studies had low risk of bias from missing data. None of the RCTs clearly described methods of sequence generation or allocation concealment.
Obsessive-compulsive disorder (three RCTs, two non-RCTs): For work-related outcomes, exposure-in-vivo applied by computer or clinician was significantly more effective than systematic self-relaxation, with a medium effect size (SMD 0.35, 95% CI 0.08 to 0.79 and SMD 0.72, 95% CI 0.28 to 1.17; one RCT, 218 participants). Exposure-in-vivo with clomipramine was significantly more effective than clomipramine plus anti-exposure work at home (p=0.03, SMD not calculable, one RCT, 24 participants). There was no significant difference between exposure-in-vivo and marital therapy (one RCT, 11 participants). Pooling of two non-RCTs found a significant benefit from exposure-in-vivo versus no exposure, with a medium effect size (SMD 0.72, 95% CI 0.28 to 1.15, I2=0%).
PTSD (one RCT, one non-RCT): For work-related outcomes, prolonged exposure-in-vivo with or without cognitive restructuring was more effective than waiting-list control at improving work-related effects, with large and medium effect sizes (SMD 0.82, 95% CI 0.12 to 1.52 and SMD 0.77, 95% CI 0.02 to 1.51; one RCT, 171 participants).
Results for anxiety disorders were similar. The review reported results for PTSD symptoms and for individual non-RCTs.
Treatments for anxiety that include exposure-in-vivo can reduce work-related problems in workers with obsessive-compulsive disorder or PTSD more effectively than other anxiety treatments or a waiting list.
The objectives and inclusion criteria of the review were clear. The included studies were not clearly applicable to the review question, because few studies reported the work status of participants. It did not appear that the inclusion criteria were adhered to with respect to participant age. Relevant sources were searched for studies. It was unclear whether the search was limited by language and publication status and potential for publication bias was not discussed. Steps were taken to minimise risks of reviewer bias and error by having more than one reviewer independently select studies, undertake validity assessment and extract data.
The choice of the GRADE tool to assess study validity was questionable as this tool was designed to assess a body of evidence rather than individual studies. Specific criteria applied to individual studies were relevant, at least for RCTs. Generally study quality appeared poor and there were very few studies and some had very small samples. The authors appropriately decided not to attempt statistical pooling for most outcomes, due to marked clinical heterogeneity between the studies. As the authors noted, in all studies exposure-in-vivo was delivered as part of a broader therapy and this made it impossible to evaluate the specific effect of the intervention. The degree of compliance with the intervention was unknown.
The authors' conclusions require cautious interpretation due to limitations in the review, particularly the paucity of data and lack of information about whether participants truly represented workers.
Implications of the review for practice and research
Practice: The authors stated that caution was required in applying review findings to workers with OCD, and that it was debatable whether the findings were applicable to workers with other types of anxiety disorder (such as PTSD).
Research: The authors stated a need for research to investigate how occupational health professionals and clinicians can make use of evidence about exposure-in-vivo. RCTs should compare exposure-in-vivo with other treatments for anxiety and should assess outcomes such as work functioning and sickness absence using reliable and valid measures.
STECR Aladdin programme, The Netherlands.
Noordik E, van der Klink JJ, Klingen EF, Nieuwenhuijsen K, van Dijk FJ. Exposure-in-vivo containing interventions to improve work functioning of workers with anxiety disorder: a systematic review. BMC Public Health 2010; 10:598
Subject indexing assigned by NLM
Anxiety Disorders /physiopathology; Clinical Trials as Topic; Efficiency; Employment; Health Promotion /methods; Humans; Meta-Analysis as Topic; Occupational Health; Sick Leave
Date bibliographic record published
Date abstract record published
This is a critical abstract of a systematic review that meets the criteria for inclusion on DARE. Each critical abstract contains a brief summary of the review methods, results and conclusions followed by a detailed critical assessment on the reliability of the review and the conclusions drawn.