Is exposure in vivo cost-effective for chronic low back pain? A trial-based economic evaluation.

BACKGROUND: Back pain is one of the most expensive health complaints. Comparing the economic aspects of back pain interventions may therefore contribute to a more efficient use of available resources. This study reports on a long-term cost-effectiveness analysis (CEA) and cost-utility analysis (CUA) of two treatments as viewed from a societal perspective: 1) exposure in vivo treatment (EXP), a recently developed cognitive behavioral treatment for patients with chronic low back pain who have elevated pain-related fear and 2) the more commonly used graded activity (GA) treatment. METHODS: Sixty-two patients with non-specific chronic low back pain received either EXP or GA. Primary data were collected at four participating treatment centers in the Netherlands. Primary outcomes were self-reported disability (for the CEA) and quality-adjusted life years (for the CUA). Program costs, health care utilization, patient and family costs, and production losses were measured by analyzing therapy records and cost diaries. Data was gathered before, during, and after treatment, and at 6 and 12 months after treatment. Non-parametric bootstrap analyses were used to quantify the uncertainty concerning the cost-effectiveness ratio. In addition, cost-effectiveness planes and cost-effectiveness acceptability curves were performed. RESULTS: EXP showed a tendency to reduce disability, increase quality adjusted life years and decrease costs compared to GA. The incremental cost-effectiveness ratios of both the CEA and CUA are in favor of EXP. CONCLUSIONS: Based on these results, implementing EXP for this group of patients seems to be the best decision. TRIAL REGISTRATION: ISRCTN88087718.

Exposure in vivo versus operant graded activity in chronic low back pain patients: results of a randomized controlled trial.

Since pain-related fear may contribute to the development and maintenance of chronic low back pain (CLBP), an exposure in vivo treatment (EXP) was developed for CLBP patients. We examined the effectiveness as well as specific mediating mechanisms of EXP versus operant graded activity (GA) directly and 6 months post-treatment in a multi-centre randomized controlled trial. In total, 85 patients suffering from disabling non-specific CLBP reporting at least moderate pain-related fear were randomly allocated to EXP or GA. It was demonstrated that EXP, despite excelling in diminishing pain catastrophizing and perceived harmfulness of activities, was equally effective as GA in improving functional disability and main complaints, although the group difference almost reached statistical significance favouring EXP. Both treatment conditions did not differ in pain intensity and daily activity levels either. Nor was EXP superior to GA in the subgroup of highly fearful patients. Irrespective of treatment, approximately half the patients reported clinically relevant improvements in main complaints and functional disability, although for the latter outcome the group difference was almost significant favouring EXP. Furthermore, the effect of EXP relative to GA on functional disability and main complaints was mediated by decreases in catastrophizing and perceived harmfulness of activities. In sum, this study demonstrates that up to 6 months after treatment EXP is an effective treatment, but not more effective than GA, in moderately to highly fearful CLBP patients, although its superiority in altering pain catastrophizing and perceived harmfulness of activities is clearly established. Possible explanations for these findings are discussed.

Measuring perceived harmfulness of physical activities in patients with chronic low back pain: the Photograph Series of Daily Activities--short electronic version.

UNLABELLED: Cognitive-behavioral models of chronic low back pain (CLBP) predict that dysfunctional assumptions about the harmfulness of activities may maintain pain-related fear and disability levels. The Photograph Series of Daily Activities (PHODA) is an instrument to determine the perceived harmfulness of daily activities in patients with CLBP. This study examined the psychometric properties of a short electronic version of the PHODA (PHODA-SeV). The results show that the PHODA-SeV measures a single factor and has a high internal consistency. The test-retest reliability and stability of the PHODA-SeV over a 2-week time interval are good, with discrepancies between 2 measurements over 20 points suggesting true change. The construct validity is supported by the finding that both self-reported pain severity and fear of movement/(re)injury were uniquely related to the PHODA-SeV. Validity is further corroborated by the finding that patients who have received exposure in vivo, that aimed to systematically reduce the perceived harmfulness of activities, had significantly lower PHODA-SeV scores after treatment than patients receiving graded activity that did not address these assumptions. The findings support the PHODA-SeV as a valid and reliable measure of the perceived harmfulness of activities in patients with CLBP. Preliminary normative data of the PHODA-SeV are presented. PERSPECTIVE: This article describes a pictorial measurement tool (PHODA-SeV) for the assessment of the perceived harmfulness of activities in patients with chronic low back pain. The PHODA-SeV has good psychometric properties and can be used to elaborate on the contribution of beliefs about harmful consequences of activities to pain and disability.

Measuring fear of movement/(re)injury in chronic low back pain using implicit measures.

Fear of movement/(re)injury is assumed to contribute to the development and maintenance of chronic low back pain (CLBP) in a subgroup of patients. Studying fear of movement/(re)injury with implicit attitude measures, without the awareness of the patient, might be a valuable addition to self-report questionnaires. The aims of the current study were to investigate whether CLBP patients demonstrate more implicit fear of movement/(re)injury than healthy controls, and whether 2 implicit measures are related to each other, and to an explicit self-report measure of fear of movement/(re)injury. A group of 66 CLBP patients and 30 healthy controls took part in this study. In addition to self-report questionnaires, fear of movement/(re)injury was implicitly assessed by the Extrinsic Affective Simon Task (EAST) and the Go-No-Go-Association Task (GNAT) that aimed to determine the association between back-stressing movements and the evaluation "threatening". On both implicit tasks it was found that neither CLBP patients nor healthy controls demonstrated implicit fear of movement/(re)injury, and that CLBP patients did not differ from healthy controls in their level of implicit fear of movement/(re)injury. In general, no associations were found between the EAST and the GNAT, or between implicitly measured and self-reported fear of movement/(re)injury. One major caveat in drawing inferences from these findings is the poor reliability of these implicit measures. Research towards the psychometric properties of these measures should first be expanded before modifying, and applying, them to more complex domains such as fear of movement/(re)injury.

Pain-related fear in low back pain: a prospective study in the general population.

A cognitive behavioural account of chronic low back pain (CLBP) proposes that the relationship between pain catastrophizing and functional disability is mediated by fear of movement/(re)injury. Several clinical studies already demonstrated the contribution of pain catastrophizing and fear of movement/(re)injury in the development and maintenance of CLBP. This study included people with low back pain (LBP) in the general population, and aimed to investigate whether fear of movement/(re)injury mediated the relationship between pain catastrophizing and functional disability, by examining several prerequisites for mediation. Data from the Dutch population-based Musculoskeletal Complaints and Consequences Cohort (DMC(3)) study were used, including 152 people suffering from LBP who completed both a follow-up questionnaire and a baseline questionnaire 6 months previously. This study was unable to demonstrate that the relationship between pain catastrophizing and functional disability was mediated by fear of movement/(re)injury, since the prerequisite that pain catastrophizing and functional disability were related, was not fulfilled. However, pain catastrophizing was significantly related to fear of movement/(re)injury 6 months later, above and beyond other contributing variables such as fear of movement/(re)injury already present at baseline. On its turn, fear of movement/(re)injury was related to functional disability, in addition to pain intensity. Although this study leaves some indistinctness concerning the actual relationships between pain catastrophizing, fear of movement/(re)injury, and functional disability, it does provide some evidence for the contributing role of these factors in LBP in the general population.

The fear-avoidance model of musculoskeletal pain: current state of scientific evidence.

Research studies focusing on the fear-avoidance model have expanded considerably since the review by Vlaeyen and Linton (Vlaeyen J. W. S. & Linton, S. J. (2000). Fear-avoidance and its consequences in chronic musculoskeletal pain: a state of the art. Pain, 85(3), 317--332). The fear-avoidance model is a cognitive-behavioral account that explains why a minority of acute low back pain sufferers develop a chronic pain problem. This paper reviews the current state of scientific evidence for the individual components of the model: pain severity, pain catastrophizing, attention to pain, escape/avoidance behavior, disability, disuse, and vulnerabilities. Furthermore, support for the contribution of pain-related fear in the inception of low back pain, the development of chronic low back pain from an acute episode, and the maintenance of enduring pain, will be highlighted. Finally, available evidence on recent clinical applications is provided, and unresolved issues that need further exploration are discussed.