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- PATIENTS AND METHODS
- AUTHOR CONTRIBUTIONS
Fibromyalgia syndrome (FMS) is defined by widespread pain (at least 3 quadrants of the body and axial) for at least 3 months, and tenderness at 11 or more of 18 tender points located throughout the body (1). Patients diagnosed with FMS also report poor coping ability (2, 3) and display overt expressions of pain (i.e., pain behaviors [4, 5]), suggesting that psychological processes may contribute to the maintenance of symptoms and disability (6, 7).
The efficacy of a diverse set of interventions has been inconsistent. Moreover, even when the results of treatment are statistically significant, a large proportion of patients do not report clinically significant outcomes. Thus, despite many clinical trials, there is no consensus regarding optimal management of FMS. A clinical practice guideline has been proposed (8) emphasizing education, exercise, antidepressant medication, and cognitive–behavioral therapy (CBT).
Multidisciplinary treatments for FMS with a cognitive–behavioral orientation result in significant changes in pain-related convictions of control, reductions in pain intensity and interference with life, and improvements in emotional distress (9, 10). In a previous study, a clinically significant reduction in pain severity measured with the reliability change index (11) was found in 42% of the sample and was maintained for 6 months (10). One recent meta-analysis of CBT in patients with FMS, however, questioned the efficacy of CBT (12).
Operant–behavioral therapy (OBT), based on the principles of operant conditioning and the importance of the antecedents and consequences of behavior (13), has been reported to produce a significant and stable reduction in pain intensity, interference, pain behaviors, health care utilization, and improvement in sleeping for patients with FMS (14–16). Sixty-five percent of the patients treated with OBT reported clinically significant improvement compared with none of the patients who received physical therapy alone (15). Although the results reported with OBT are promising, there have only been a few studies that have evaluated the effectiveness of this treatment in patients with FMS.
A previous comparison of CBT and OBT revealed that CBT influenced pain-related, cognitive, and affective variables, whereas OBT showed improvements in functioning and behavioral variables in addition to pain intensity (15, 17). Therefore, these treatments appear to have an impact on different variables. Even though the results that have been reported indicate statistically significant improvements on some outcome criteria, a significant percentage of patients do not demonstrate clinically significant benefits (17). Most of the published clinical outcome studies have treated patients as homogeneous groups based on the diagnosis of FMS despite the patient heterogeneity observed in both physiologic variables (18–20) and psychosocial characteristics (2, 21, 22). The results observed with CBT and OBT raise an important question regarding which patients are most likely to benefit from these treatments, which have different emphases.
Several articles (3, 10, 23, 24) report predictors for treatment efficacy in patients with chronic back pain, temporomandibular pain, FMS, and rheumatoid arthritis following various psychological treatments. Although the efficacy of electromyogram biofeedback was predicted by chronicity and treatment-specific variables such as low reactivity of the affected muscles, the efficacy of CBT was predicted by cognitions and coping resources (3, 10, 24), duration of the disorders (24), depression, and low solicitous behavior (10).
This report contains a secondary analysis of the results of a previous study (17) comparing the effectiveness of CBT with OBT and with an attention placebo control (AP) in patients with FMS. The results of the previous study indicated that although both treatments provided evidence supporting the efficacy of the 2 treatments compared with a control group, not all patients achieved the same positive outcomes. The primary goal of the present study was to identify the characteristics of CBT and OBT responders and to compare them with each other and with an AP group. Identification of responder criteria could serve as the basis for prospective treatment to determine whether prescribing treatments based on identified responder criteria would produce improved outcomes compared with offering generic treatments to all patients with FMS.
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- PATIENTS AND METHODS
- AUTHOR CONTRIBUTIONS
Examination of the responders revealed that 45% of the patients treated with CBT demonstrated clinically significant reduction in pain maintained over 12 months following treatment. The responder rate was comparable with that in the study by Turk et al (10). Consistent with previous studies (9, 10), successfully treated patients reported reduced pain intensity, less affective distress, more coping, and less catastrophizing. OBT responders (54%) showed reduced physical impairment, fewer physician visits, and reduced pain behaviors.
The results obtained are also consistent with other studies of patients with FMS treated with psychological approaches (15, 16). The CBT and OBT groups had larger clinically significant reductions in physical impairment compared with the AP group. In contrast to 7.5% of the patients in the AP group, 58% of the patients treated with OBT and 38% of the patients treated with CBT significantly reduced their physical impairment.
The clinically significant deterioration of 47.5% of the patients in the AP group was related to extremely high pain behaviors and physical impairment. These variables suggest that the social discussion (AP) may have inadvertently reinforced pain and disability in a group that was already prone to operant reinforcement of pain. The pain behaviors and physical impairment of the CBT and OBT negative responders (6.9% and 14.3%, respectively) were not significantly different compared with the AP negative responders. In contrast, CBT and OBT responders with clinically significant improvements showed significantly lower pain behaviors and physical impairment than the negative responders. All negative responders showed high pain behaviors and levels of physical impairment. That is, patients with extreme values did not profit from any psychological treatment.
Pain responders to a psychological treatment had lower pretreatment physical impairment in accordance with Williams (34). Psychological variables did not predict significant reductions in pain. This is not surprising because pain reduction is not the primary end point for psychological treatments. Rather, improvement in physical functioning is typically the objective.
High levels of physical impairment and pain behavior and lower affective distress and reduced solicitous spouse behavior predicted improvement in physical functioning. Consistent with these results, Turk and colleagues (10) found that treatment failure was associated with a high level of emotional distress, high perceived disability, and low perceived life control.
Several variables differentiated patients who benefited from CBT from those who improved with OBT. Whereas patients with more pain behaviors and physical impairment, a higher number of physician visits, more solicitous spouse behaviors, and a higher level of catastrophizing benefited more from OBT, patients with lower pain behaviors, higher levels of affective distress, lower coping, and reduced solicitous spouse behaviors appeared to obtain the greatest benefits from CBT. These results are consistent with other studies (3, 23, 24) that found that coping, cognitive factors, and seeking support from others accounted for 18% of the variance in improvement of pain-related interference (3, 10).
Pain behaviors were the most important predictor that discriminated the efficacy of CBT in comparison with OBT and AP. Whereas CBT responders showed low pain behaviors, OBT responders displayed high pain behaviors. In addition, patients with high pain behaviors in the AP group showed a clinically significant deterioration of physical impairment. This finding suggests that patients with low pain behaviors need to restructure maladaptive cognitions, whereas patients with high pain behaviors need to rebuild healthy behavior to achieve the reduction of physical impairment.
The large number of dropouts in the AP group raises a concern about the credibility of AP compared with the 2 active psychological approaches. Analysis of treatment satisfaction reported in the companion article (17), however, indicated that there were no significant differences between the groups. However, satisfaction variables in the AP group were not assessed from the dropouts.
The results of this study support the observation that patients with FMS are not homogeneous (20, 21, 35). The results indicate that treatment responders varied on important characteristics that appear amenable to treatment. Therefore, the results obtained raise the potential for improved outcomes by matching treatments to patient characteristics as originally suggested by Turk and Flor (36). One explanation for the inconsistency in results of CBT and OBT observed in the literature is that some patients were receiving treatments that were incompatible with important features present prior to treatment. The mismatch might have led to poorer outcome. Some studies have reported on the potential benefits of treatment matching (15, 36, 37), but not all studies have done so (35). Prospective studies are needed to provide a better understanding of the potential of treatment matching for patients with FMS.