Elsevier

The Spine Journal

Volume 14, Issue 12, 1 December 2014, Pages 2868-2876
The Spine Journal

Clinical Study
Multiple somatic symptoms in employees participating in a randomized controlled trial associated with sickness absence because of nonspecific low back pain

https://doi.org/10.1016/j.spinee.2014.01.062Get rights and content

Abstract

Background context

The prevalence of multiple somatic symptoms is high in primary and hospital outpatient populations. Multiple somatic symptoms may be present in patients sick-listed because of low back pain (LBP) and may be associated with increased risk of not returning to work (RTW).

Purpose

To explore whether multiple somatic symptoms in a subset of patients with nonspecific LBP was associated with RTW, sickness absence (SA), or other social benefits.

Study design

The study was a cohort study based on a randomized clinical trial with a prospective 2-year follow-up period. Patients were referred from general practices to the Spine Center, Regional Hospital Silkeborg, Denmark.

Patient sample

Patients were 285 sick-listed employees (4–12 weeks), with nonspecific LBP as their prime reason for SA. Exclusion criteria were unemployment, radiculopathy, LBP surgery within the past year, previous lumbar fusion, suspected cauda equina syndrome, progressive paresis or other serious back disease, pregnancy, known substance abuse, or primary psychiatric diagnosis.

Outcome measures

Self-reported health was assessed by the LBP rating scale and questions about pain and health in general. Disabilities were measured by the Roland Morris Questionnaire, the Short Form-36, and the Fear-Avoidance Beliefs Questionnaire. Work-related questions comprised expectations about RTW and risk of losing job because of SA. The Common Mental Disorder Questionnaire (subscale SCL-SOM) was used to assess multiple somatic symptoms (12 items). We categorized multiple somatic symptoms into four groups based on the SCL-SOM sum score: <6, 6 to 12, 13 to 18 and >18. Status of SA (>2 weeks) and RTW were gathered from a national database (DREAM).

Methods

The patients (N=285) were randomized into either multidisciplinary or brief intervention at the Spine Center (2004–2008). Both interventions comprised clinical examination and advice by a physiotherapist and a rheumatologist. Data were collected from questionnaires at baseline (inclusion) and 1 year after inclusion. Data on SA benefits were gathered from the DREAM database that contains data on all social transfer payments (such as sick leave benefits and other disability benefits) registered on a weekly basis.

Results

All health factors, female gender, and poor work ability were significantly associated with a higher level of multiple somatic symptoms. The percentage of persons with SA increased significantly with the symptom score after 1 year, and the duration of SA remained significantly longer after 2 years of follow-up between the multiple somatic symptoms groups. The percentages with RTW after 1 and 2 years were negatively associated with a higher level of multiple somatic symptoms at baseline. We found no difference between the intervention groups.

Conclusions

A higher level of multiple somatic symptoms was significantly associated with poor health and work ability at baseline and with longer duration of SA and unsuccessful RTW through a 2-year follow-up period.

Introduction

Evidence & Methods

Somatization has long been felt to adversely impact outcomes in the setting of low back pain, as well as other musculoskeletal disorders. The role of somatization as an impediment to recovery from debilitating low back pain (and capacity to work) warrants further exploration. The authors performed an investigation of this effect, using data collected as part of a randomized prospective trial.

Perhaps not surprisingly, the authors maintain that the presence of multiple somatic symptoms was negatively correlated with return to work. Likewise, the duration of absence from work was significantly longer for those individuals with the highest levels of multiple somatic symptoms.

The results of this study reinforce concepts long maintained to be true regarding the impact of somatization on work-capacity and functional outcomes in the setting of spinal disorders. As a post-hoc analysis of data collected during a randomized clinical trial, it should be recognized that this study was not specifically designed to detect differences between patients with different levels of somatization. In addition, the fact that patients in this study were randomized to different treatments, irrespective of their somatization level, may have biased some of the results presented here. Finally, as with all studies conducted in a different ethno-cultural context, the findings of this study and its conclusions might not necessarily be generalizable to patients with back pain in the United States or elsewhere.

—The Editors

Patients with high levels of so-called medically unexplained somatic symptoms are frequent in both primary care and hospital outpatient populations [1], [2], [3], and persons with many of these symptoms are often not working [4]. The prevalence of severe somatic symptoms was 15% in a sick-listed population, and 15% to 30% of the patients with multiple symptoms did not recover or got worse during sick-listing [5]. Multiple somatic symptoms are commonly associated with illness worry (health anxiety) and poor functional status [6]. Common somatic symptoms include musculoskeletal pain, fatigue, dizziness, and noncardiac chest pain. It has been reported that multiple somatic symptoms are associated with disability independent of comorbidity and that health anxiety contributes to a longer duration of sickness absence (SA) [5]. In the literature, a high level of multiple somatic symptoms is also referred to as bodily distress [7], [8].

High levels of multiple somatic symptoms are diagnosed differently by different medical specialities; these syndromes (eg, chronic fatigue, irritable bowel, fibromyalgia) are very alike based on subjective complaints, and they are not well explained by traditional medical methods [7], [8]. Within rheumatology, “low back pain (LBP)” is often used as a diagnostic label for nonspecific symptoms. However, LBP is at times associated with specific anatomic and structural disease; therefore LBP may not be classified as medically unexplained. Still, structural changes can explain the pain in only a fraction of LBP patients [9].

Patients with LBP often do not return to work (RTW) and knowledge of factors associated with RTW failure should be identified to inform due interventions. Psychological distress has been documented as a risk factor for RTW [10], and an overlap between multiple somatic symptoms and psychological distress measured by the “General Health Questionnaire” has been documented [11].

The overall rate of RTW in our first study including sick-listed LBP patients with radiculopathy and specific and nonspecific disorders in the secondary health care system was 73.5% during the first year [12].

The primary aim of the present study was to explore whether multiple somatic symptoms at baseline in a subset of patients with nonspecific LBP was associated with SA, RTW, unemployment, or social benefits throughout the first 2 years after a sick-listing episode. Secondary aims were to investigate whether multiple somatic symptoms decreased after intervention and whether there were any differences between the intervention groups.

Section snippets

Design

The study was a cohort study based on a randomized clinical trial with a prospective 2-year follow-up period. A comprehensive description of the trial and the interventions is described in the study by Jensen et al. [12]. This original study included 351 patients enrolled from 2004 to 2007 and was followed by a validation study including 120 patients. Overall, there were no differences in outcomes between the intervention groups.

Patients

In short, 471 patients were included in the study from 11

Results

The baseline characteristics of the patients are presented in four multiple somatic symptoms groups based on SOM sum scores at baseline as shown in Table 1. The mean baseline SOM score for all patients who responded to the CMDQ (N=282) was 14.3. Health anxiety (Whiteley-7) and all other scores for health factors were significantly associated with an increased level of multiple somatic symptoms. Female gender and poor work ability also showed statistically significant associations with increased

Discussion

We found associations between high levels of multiple somatic symptoms and poor health and work ability. In addition, a low rate of RTW and high SA were significantly associated with high levels of multiple somatic symptoms.

These findings are in line with earlier findings that showed that a high number of somatic symptoms resulted in more and longer lasting disabilities [6], [20] and longer SA [5], [20]. However, one study found the reverse for most of the disability variables [21]. Terluin

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    FDA device/drug status: Not applicable.

    Author disclosures: A-MHM: Grant: Tryfonden (A, Paid directly to institution). OKJ: Nothing to disclose. CVN: Grant: Tryfonden (A, Paid directly to institution). CJ: Grant: Tryfonden (A, Paid directly to institution).

    The disclosure key can be found on the Table of Contents and at www.TheSpineJournalOnline.com.

    The study was supported by a grant from Trygfonden (FL-54).

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