Mindfulness-Based Stress Reduction for Treating Low Back Pain

Low back pain is a major public health problem. Approximately 12% to 30% of the population has such pain annually (13), and lifetime prevalence is approximately 75% (4). In the past decade, it has become a leading cause of disability worldwide, placing a major burden on individuals and health care systems (47). Because an optimal clinical treatment has yet to be identified for this condition, patients often seek complementary therapies (810). Mindfulness-based interventions, such as mindfulness-based stress reduction (MBSR) and mindfulness-based cognitive therapy (MBCT), are complementary therapies commonly used to treat pain (11). The concept of mindfulness derives from the Buddhist spiritual tradition and has been secularized and integrated into behavioral treatment approaches (12). Mindfulness-based stress reduction programs were originally developed in behavioral medicine settings for patients with chronic pain and stress-related conditions (13, 14). They are typically delivered as structured 8-week programs consisting of weekly 2.5-hour group sessions and an all-day (7- to 8-hour) silent retreat. Key components of the MBSR program include sitting meditation; walking meditation; hatha yoga and body scan; and sustained mindfulness practice, in which attention is sequentially focused on different parts of the body (15). Another important component is the incorporation of mindfulness into everyday life. Mindfulness-based cognitive therapy combines MBSR with cognitive behavioral techniques (16, 17) and retains the 8-week group-based approach. Originally developed as a treatment for major depression (16), MBCT has been adapted for other conditions (17). Other mindfulness-based interventions include mindful exercise (18) and acceptance, as well as commitment therapy (19). These interventions may not include formal meditation. Pain has always been a key focus of MBSR research (13). Several trials assessed the effect of MBSR on patients with heterogeneous chronic pain conditions and reported mainly positive results (2024). A recent systematic review and meta-analysis, which examined systematic reviews of randomized controlled trials (RCTs) of standardized mindfulness-based interventions for treatment of various chronic conditions, found small to medium effects on physical functioning, depression, anxiety, stress, and quality of life (25). Of note, this review included only 1 meta-analysis involving patients with chronic pain, which itself included only 1 low back pain trial (19). Thus, in this systematic review and meta-analysis, we examined the efficacy and safety of MBSR and MBCT interventions in managing low back pain. Methods We followed the PRISMA (Preferred Reporting Items for Systematic reviews and Meta-Analyses) guidelines (26) and the recommendations of the Cochrane Collaboration (27) in conducting this systematic review and meta-analysis. Data Sources and Searches We searched MEDLINE/PubMed, Scopus, the Cochrane Library, and PsycINFO from inception through 15 June 2016. We did not search EMBASE separately because it is included in Scopus. The complete search strategy for MEDLINE was as follows: (MBSR[Title/Abstract] OR MBCT[Title/Abstract] OR mindful*[Title/Abstract] OR mindfulness[Mesh] OR meditation[Title/Abstract] OR meditation [Mesh]) AND (low back pain[Mesh] OR low back pain[Title/Abstract] OR lower back pain[Title/Abstract] OR lumbago[Title/Abstract] OR low backache[Title/Abstract] OR low back ache[Title/Abstract] OR sciatica[Mesh] OR sciatica[Title/Abstract]). This search strategy was adapted for the remaining databases as needed. No language restrictions were applied. The reference lists of identified original articles or reviews were also searched manually to retrieve additional articles. Study Selection Studies were eligible for this review if they were RCTs that included patients with low back pain of any cause, duration, or intensity; compared MBSR or MBCT interventions with either a passive comparator (usual care) or an active comparator (such as health education or cognitive behavioral therapy); and assessed pain intensity or pain-related disability as primary outcomes. Studies were excluded if they were observational studies or nonrandomized trials, tested interventions that clearly differed from the original MBSR or MBCT programs (for example, acceptance and commitment therapy or dialectic behavioral therapy), or had not been published as full-text articles in peer-reviewed scientific journals. Health-related quality of life, pain acceptance, mindfulness, safety, and patient adherence were defined as secondary outcomes. Two pairs of reviewers (D.A. and H.H., and H.C. and R.L.) independently read all of the retrieved articles in full to determine their eligibility for inclusion. Discrepancies were rechecked and then discussed until consensus was reached. Data Extraction and Quality Assessment The same pairs of reviewers extracted data independently from the eligible studies on study characteristics (such as trial design, randomization, and blinding), sample characteristics (such as sample size, age, and diagnosis), characteristics of the intervention and comparison treatments (such as type, program length, and frequency and duration of sessions), information about dropouts, short- and long-term outcomes, and safety and adherence assessments. Discrepancies among the reviewers were rechecked and discussed until consensus was reached. Risk of Bias in Individual Studies Risk of bias was assessed independently by 2 reviewers (D.A. and H.H.) using the Cochrane risk-of-bias tool. This tool assesses risk of bias in the following domains: selection, performance, detection, attrition, reporting, and other bias (27). Resulting discrepancies were rechecked by a third reviewer (H.C.), and consensus was achieved by further discussion. The original trial authors were contacted for further details if necessary. Data Synthesis and Analysis Separate meta-analyses were conducted for studies comparing MBSR or MBCT with usual care or an active comparator. Studies with short- and long-term follow-up were also analyzed separately. For the purpose of this review, short-term follow-up was defined as outcome measurements made closest to 8 weeks after randomization (the typical length of an MBSR intervention). Long-term follow-up was defined as measurements made approximately 6 months after randomization. Meta-analyses were conducted if at least 2 studies had sufficient statistical and clinical homogeneity to assess a specific outcome. Standardized mean differences (SMDs) and their 95% CIs were calculated as the between-group difference in means divided by the pooled SD, using the Hedges correction for small study samples (27). When no SDs were cited, they were calculated from the SEs, CIs, or t-statistics presented (27) or attempts were made to obtain this information from the original trial authors. For pain intensity and disability, a negative SMD indicated beneficial effects for the MBSR or MBCT group versus the comparison group. For quality of life, pain acceptance, and mindfulness, a positive SMD indicated beneficial effects for the mindfulness-based intervention. Summary SMDs and 95% CIs were reexpressed as mean differences (MDs), using the units of the measurement instruments in the selected studies, to facilitate clinical interpretation of the observed treatment effects. This was achieved by multiplying the SMDs and CIs by the pooled SD of the baseline scores, either from available epidemiologic studies or from the largest related RCT using the same measurement instrument (27). A summary of the instruments used and the range of values, verbal anchors, and minimal clinically important differences (MCIDs) used for each outcome are given in Table 1. Random-effects meta-analysis estimates were obtained using the metafor package (www.metafor-project.org) in R, version 3.3. 2 (R Foundation for Statistical Computing). The KnappHartung small-sample correction was used because it provides a more adequate accounting of uncertainty when treatment effects from a small number of heterogeneous studies are pooled (28, 29). Table 1. Summary of Measures Assessment of Heterogeneity Statistical heterogeneity between studies was explored using I 2 and chi-square statistics. I 2 values greater than 25%, greater than 50%, and greater than 75% indicate moderate, substantial, and considerable heterogeneity, respectively (27). A P value of 0.10 or less from the chi-square test indicates significant heterogeneity (27). Risk of Bias Across Studies We originally planned to assess for publication bias by inspecting funnel plots visually but were unable to do so because of the small number of eligible trials (30). Role of the Funding Source No external funding was obtained for this review. Results The original database search retrieved 212 potentially relevant references, from which 10 full-text articles were evaluated for potential inclusion in this review (Appendix Figure 1). Eight articles describing 7 RCTs that involved a total of 864 patients were eligible for qualitative analysis (3138). Appendix Figure 1. Flow chart of literature search. Study Characteristics Table 2 presents the study characteristics of the 7 RCTs included in this review. Six RCTs were conducted in the United States, and 1 was done in Iran (31). Patients were recruited from a multidisciplinary spine and rehabilitation center (33), an adult pain clinic (35), and a physiotherapy center (31). Others were recruited via posted flyers, newspaper advertisements (34, 35, 38), direct mail, or telephone contact (32, 34, 36). Patients in 3 RCTs were older adults (aged 65 years) with chronic low back pain (duration 3 months) (3436). In the remaining RCTs, participants' ages ranged from 20 to 70 years, and pain duration ranged from 3 or more to 6 or more months. The trials included patients with nonspecific low back pain (31, 32, 3437), as well as patients with low back pain