Effects of a mindfulness-based intervention on pain intensity, disability and quality of life of chronic low back pain patients: A randomised study

INTRODUCTION The lifetime prevalence of low back pain was 66% among Indians (2022).[1] Chronic low back pain (CLBP) is multifactorial and refers to non-specific localised back pain below the costal margin and above the inferior gluteal folds with a duration of >3 months. CLBP was previously treated only with medicines and invasive procedures, but the newer bio-psycho-social model demands a multimodal treatment approach. Mindfulness is defined as ‘the awareness that arises on paying attention in a particular way on purpose, in the present moment, and nonjudgmentally’ and has been used as a group behavioural intervention.[2] The initial mindfulness-based stress reduction (MBSR) modules evolved into equally effective brief mindfulness-based intervention (MBI) modules. The mechanism of pain relief in mindfulness involves higher-order (rostral anterior cingulate cortex) regulation of lower nociceptive targets (thalamus and primary somatosensory cortex).[3,4] The study’s primary objective was to determine an MBI’s effectiveness in pain intensity, disability, and quality of life. The secondary objective was to observe the effects on stress, anxiety, depression, pain acceptance, pain catastrophising and mindfulness characteristics in the Indian population. We hypothesised that mindfulness will improve pain intensity, disability and quality of life. METHODS This randomised controlled trial (RCT) was conducted from August 2023 to February 2024. Written informed consent was obtained from all the participants to enrol them in the study and use the patient data for research and educational purposes. An Institutional Ethics Committee clearance (KPCMCH/IEC/2023/135, dated 10 July 2023) was obtained, and the trial was registered with Clinical Trials Registry-India (CTRI/2023/08/056037, https://ctri.nic.in/). The study was carried out following the principles of the Declaration of Helsinki, 2013 and good clinical practice. Patients of age 18–65 years, suffering from CLBP >3 months, had a definitive provisional diagnosis of CLBP (excluding infection, neoplasm, metastasis, etc.), had an intensity of pain of numerical rating scale (NRS) >4 and were on a stable treatment regimen were recruited. Patients with previous experience with mindfulness, patients suffering from uncontrolled systemic diseases, patients with a history of back surgery and patients with pain in other parts of the body, like fibromyalgia, were excluded from the study. The principal investigator randomised [sequence produced through the Statistical Package for the Social Sciences (SPSS) software’s random selection procedure] the patients as per the random sequence to Group U (usual care) or Group M (mindfulness). The allocation concealment was done using a set of sealed envelopes chosen by the participants. Those who attended at least three of five sessions were retained in the study. The usual medical treatment regimen of the patients [receiving medicines like paracetamol (650 mg thrice a day), pregabalin 75 mg, amitriptyline 10 mg, etc.] was continued, and mindfulness or usual care was used as an additional therapy. A five-session version of the MBSR programme was chosen [Table 1]. The programme was conducted by a pain physician trained via the original MBSR programme (https://www.ummhealth.org/center-mindfulness) and with teaching experience of more than four years. The participants maintained a daily practice log of home practice, which was monitored by the teacher, and regional language was used in most of the communication. Group U attended sham sessions and practised relaxation exercises (mindfulness concepts were excluded). Any participant experiencing any adverse effects was taken care of by a neuro-psychiatrist.Table 1: Mindfulness (and usual care) intervention details and demographic profileThe demographic characteristics were noted. The outcome variables were assessed using a self-assessment questionnaire at three time points: pre-programme, post-programme and six months from the start of the programme. The primary outcome parameters were pain intensity, disability and quality of life. The pain intensity was measured using the 11-point NRS, disability by the 10-item Oswestry Disability Index (ODI) and quality of life with 26 items World Health Organization (WHO) quality of life (WHO QOL 100) scales. The secondary parameters stress, anxiety and depression were measured using the Depression Anxiety and Stress Scale-21 items (DASS 21) and pain acceptance was measured by the Chronic Pain Acceptance Questionnaire-8 (CPAQ 8). Pain catastrophising was measured by a 13-item pain catastrophising scale (PCS), and different aspects of mindfulness were measured by the 14-item Freiburg Mindfulness Inventory (FMI). Sample size calculation was made with a standard deviation (SD) of 1.86 for the difference in pain intensity (from a study by Carrie E Brintz et al.)[5] With a power of 80% to find the difference using repeated measures analysis of variance (RM ANOVA) with a type I error (α) of 5%, the calculated minimum total sample size was 184 (or 184/2 = 92 in each group). Initially, 200 patients were screened (anticipated attrition of 10%). SPSS statistics software version 18.0 (IBM Corporation, Armonk, NY, USA) was used. The statistical test used for age [expressed as mean (SD)] was an unpaired t-test, and for gender (expressed as a percentage) was a Chi-square of independence. For the other outcome parameters, the statistical test was RM ANOVA (Bonferroni model). The normality of data was tested using the Shapiro–Wilk Test and results were presented in mean (SD) and percentage format. P < 0.05 was considered statistically significant for RM ANOVA results, and P < 0.0167 was statistically significant with Bonferroni correction. The F distribution (named after Ronald Fisher) derived from the quotient of two Chi-square distributions was used to interpret RM ANOVA results. RESULTS The flow diagram is summarised [Figure 1]. The baseline demography were comparable between the groups [Table 1]. The primary outcome parameters showed a significant difference both between Group M and Group U and between treatments (pre-session vs. post-session vs. follow-up) in NRS (F = 56.193, P = 4.851e-14), ODI (F = 65.625, P = 8.993e-15) and WHO QOL domain 1 and 2. Regarding the secondary outcome parameters, results of RM ANOVA showed a significant difference between Group M and Group U and between treatments (pre-session vs. post-session vs. follow-up) in almost all the parameters. Participants reported no adverse effects during sessions [Table 2].Figure 1: Consolidated Standards of Reporting Trials flow diagramTable 2: Comparison of study parametersDISCUSSION In Group M (mindfulness), pain intensity (NRS), disability index and quality of life (in domain 1,2) significantly improved post-session and were mainly sustained in follow-up. Stress, anxiety, depression, pain acceptance and pain catastrophising (effect size medium) showed significant improvement post-session and were mainly sustained in follow-up. Our study’s findings were congruent with those of previous studies. Anheyer et al.[6] found mindfulness to decrease pain intensity. An RCT by Morone et al.[7] showed it to reduce disability in the elderly with CLBP. A systemic review found MBIs to reduce pain intensity,[8] while another found it to improve depression and quality of life (along with pain).[9] A systemic review found mindfulness to improve pain acceptance,[10] while a study found it to decrease pain catastrophising.[11] In the Indian context Patil[12] mentioned its use in CLBP, and Banth and Ardebil[13] used mindfulness in Iranian female patients and found it to reduce pain severity and improve quality of life. Limitations include the study being a single-centre trial, the outcome variables being self-reported, the per-protocol format of analysis, significant loss of participants in follow-up, heterogeneity of received medical treatment and non-calculation of cost-effectiveness of the therapy. CONCLUSION Mindfulness had a positive impact on pain intensity, disability and quality of life of Indian chronic low back pain patients. Study data availability De-identified data may be requested with reasonable justification from the authors (email to the corresponding author) and shall be shared upon request. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.