“Yoga may work better for lower back pain than conventional treatments,” The Guardian reported. It said that a trial has found that people with back pain had greater improvements in everyday physical tasks if they did weekly yoga sessions.
This trial enrolled 313 people with chronic low back pain and gave them either a three-month yoga programme or usual care for back pain. They completed questionnaires on the level of disability they had from their low back pain at the start of the study, and three, six and twelve months later. While there was minimal change in disability scores in the usual care group, those in the yoga group reported a lower disability score on all three subsequent questionnaires.
The study has some strengths, but also several limitations including the possibility that both groups were biased towards perceiving that yoga had an effect.
Current treatment of chronic low back pain involves advising people to remain active. They are then referred for an exercise programme or physiotherapy if there is no improvement in their condition. The trial results do not demonstrate that this standard care approach is ineffective or inappropriate. Rather, they lend support to the fact that physical activity can be beneficial. However, yoga itself may not necessarily be the most appropriate form of exercise for everyone, and people with back pain should continue to follow the advice given to them by their GP or physical therapist.
Where did the story come from?
The trial was carried out by researchers from the Universities of Manchester and York and yoga clinics in York and Cornwall. The study was funded by Arthritis Research UK and was published in the peer-reviewed journal Annals of Internal Medicine .
In general, the news stories correctly reflected the main findings of this trial. However, the papers did not mention some important limitations of the study.
What kind of research was this?
This randomised controlled trial investigated the effectiveness of yoga compared to usual care (details of which are not given in the research paper) for chronic or recurrent low back pain.
The type of low back pain investigated in this trial is what would sometimes be medically called “non-specific” low back pain. This means that the cause of pain, tension or stiffness of the lower back is unclear. Non-specific back pain is not associated with any disease cause such as cancer, fracture, inflammatory conditions, infections or spinal cord compression.
This sort of low back pain is a chronic health problem that places a considerable burden on the health care system. It also causes a high level of persistent disability among sufferers, reduces capacity to work, and significantly reduces quality of life. The benefits of remaining active for people with this type of pain are well established. Some previous studies have suggested that yoga can be beneficial, and this study aimed to further assess this.
What did the research involve?
Thirty-nine general practices took part in this study and mailed invitations to patients who had low back pain over the past 18 months. The participants were asked to fill out a questionnaire evaluating the extent of their disability from back pain called the Roland–Morris Disability Questionnaire (RMDQ). This is a 24-item questionnaire with scores ranging from 0 (best) to 24 (worst). To be eligible, back pain sufferers had to have an initial RMDQ score over four, had not done yoga in the past six months, did not have a serious cause of their back pain, and did not have any other significant medical or mental health condition.
A total of 313 eligible participants (average age 46 years and mainly women) were randomly assigned by computer to receive either a yoga intervention (156 participants) or usual care (157). The yoga intervention was a gradually progressive 12-class yoga programme delivered by experienced yoga teachers over three months. All participants received a back pain education booklet. Other aspects of usual care were not specified. The usual care group was offered a one-off yoga session after the final follow-up.
The participants were sent questionnaires again by post at three months, six months and twelve months. The primary outcome was the RMDQ score at three months. Other secondary outcomes assessed by questionnaires were pain, self-efficacy (a measure of the participants’ belief in their competence), and general health and quality of life.
What were the basic results?
Around 87% of both the yoga group and usual care group completed the follow-up to 12 months, and 60% of the yoga group attended at least three of the first six yoga sessions and at least three other sessions.
Mean RMDQ score in both groups at the study's start was 7.8 points. At each follow-up point, the yoga group had better back function on the RMDQ than the usual care group:
- The mean (average) RMDQ score at three months (the main outcome) was 2.17 points lower in the yoga group than in the usual care group (95% confidence interval [CI] 1.03 to 3.31 points).
- At six months, the RMDQ score was 1.48 points lower in the yoga group (95% CI 0.33 to 2.62 points).
- At 12 months, the RMDQ score was 1.57 points lower (95% CI 0.42 to 2.71 points).
There were no differences between the yoga and usual care groups in secondary outcomes of back pain and general health scores at three, six or twelve months. Also, though the yoga group had higher pain self-efficacy scores at three and six months, the difference between the groups was not maintained at twelve months. Twelve of the 156 yoga participants (8%) reported adverse events, mostly increased pain, compared with two of the 157 usual care participants (1%). In the yoga group, one adverse event was classified as serious and possibly or probably related to the yoga. This participant reported a previous history of severe pain after physical activity.
How did the researchers interpret the results?
The researchers concluded that offering a 12-week yoga programme to adults with chronic or recurrent low back pain leads to greater improvement in back function than usual care alone.
This well-conducted randomised controlled trial enrolled a reasonably large sample of people with low back pain, analysed them over one year with validated back pain questionnaires, and used a carefully designed yoga programme provided by qualified yoga practitioners.
The trial found that yoga led to a clear improvement in back function compared to usual care. However, there are some important points to note:
- Though this was a randomised controlled trial, participants were aware of the trial’s purpose. Those who chose to take part in the trial may have been more likely to believe that yoga could work for them than people who declined to participate. This means that the trial population may not have been fully representative of all back pain sufferers.
- Participants were not blinded to the treatment that they received (they knew whether they were doing yoga or not). At the start of the trial when the researchers questioned participants’ beliefs about yoga, roughly equal proportions of both trial arms expected that yoga would work for them (57% of the yoga and 55% of the usual care groups). As the primary outcome was a subjective report (a self-completed disability questionnaire), and as the participants knew whether they had received yoga or not, it is possible that the responses of some of the people in both groups could have been biased (albeit unknowingly).
- As the researchers highlight, 13% of the yoga group and 11% of the usual care group did not complete the assessment at three months (though this could be considered an acceptable drop-out rate that should not reduce the strength of the analysis too much).
- Most of the participants (approximately two-thirds) were women. It is not clear whether the study would have had similar results if there had been equal numbers of men and women.
Usual care was not described in this study. Treatment for this type of non-specific (without disease cause) lower back pain, as currently recommended by NICE, follows a step-by-step approach. The initial focus of lower back pain management tends to be on encouraging the person to remain as active as possible, with the use of short-term painkillers (paracetamol or an anti-inflammatory drug) to control pain if required. If the person does not improve, the GP may then refer them for physical therapy, such as physiotherapy or an exercise programme.
The trial results do not demonstrate that the current standard care approach is ineffective or inappropriate. Rather, they lend support to the fact that physical activity can be beneficial for people with chronic low back pain. However, yoga itself may not necessarily be the most appropriate form of exercise for everyone, and people with back pain should continue to follow the advice given to them by their GP or physical therapist.