Another Myth Debunked

Abstract & Commentary

Synopsis: Medium-firm mattresses are better for patients with low back pain than are firm mattresses.

Source: Kovacs FM, et al. Lancet. 2003;362:1599-1604.

This report results from a larger study on prevalence and risk factors for low back pain. Participants in this study were patients who had low back pain for at least 3 months. Those with referred pain, systemic disease, cancer, pregnancy, fibromyalgia, multiple beds, and chronic pain medicine or hypnotic ingestion were excluded. Kovacs and colleagues randomized 313 adults who had chronic, nonspecific low back pain to either a medium-firm or firm mattresses. In Europe, mattresses are rated by the European Committee for Standardization (good work if you can get it!) on a 1 to 10 scale. For this study, the firm mattresses were 2.3, and the medium firm ones were 5.6. Mattresses were installed in the participants’ homes free of charge; patients and investigators were blinded to the type of mattress each patient received (although patients were fairly accurate in their judgment of the hardness of their new mattresses).

Patients were assessed at baseline and at 90 days. Primary outcomes were self-assessed intensity of pain while in bed and upon rising, as well as degree of disability. Pain was rated on a visual analogue scale, and disability was rated by a Spanish version of the Roland Morris questionnaire.1 Kovacs et al collected data on a variety of lifestyle and anthropomorphic variables. Overall, 158 patients were assigned firm mattresses, and 155 were assigned to medium-firm mattresses; these groups did not differ from each other. Also, 73% were women, with a medium age of about 44 years. Average duration of pain was 9 or 10 years.

At 90 days, both groups showed improvement in symptoms. Pain intensity while lying in bed improved 70% and 80% for the firm and medium-firm groups, respectively. There was 57% improvement in intensity of pain on rising in both groups, and 30% and 50% improvement in disability in the firm and medium-firm groups, respectively. The improvements in disability and pain on rising were statistically significant for the medium-firm group compared with baseline. Seventeen percent and 9% of those with firm and medium-firm mattresses, respectively, had worsening of pain while lying in bed after the new mattresses were installed, but no one requested a mattress change.

Comment by Barbara A. Phillips, MD, MSPH

The fact that a study about mattresses and back pain was published in The Lancet is a testimony to the prevalence of back pain and the dearth of real science about how to deal with it. Chronic low back pain is extraordinarily common, with an estimated prevalence of 20%, yet there remains no consensus regarding workup or treatment of patients who have it.2 Kovacs et al note that orthopedic surgeons strongly believe that mattresses play a role in managing low back pain and that a majority of them recommend a firm mattress, apparently on the basis of anecdotes.

In the vast majority of cases, no organic cause can be identified, although manual labor is clearly implicated in many patients.3 Back pain is the second only to headache as a chronic pain condition causing absenteeism and reduced work productivity.4 Thus, the condition is common and costly, and it is about time that management of patients with back pain be based in science rather than dogma. 

Dr. Phillips, Professor of Medicine, University of Kentucky; Director, Sleep Disorders Center, Samaritan Hospital, Lexington, KY, is Associate Editor of Internal Medicine Alert.

References

1. Kovacs FM, et al. Spine. 2002;27:538-542.

2. Erlich GE. J Rheumatol Suppl. 2003;67:26-31.

3. Cole MH, et al. Work. 2003;21:173-184.

4. Steward WF, et al. JAMA. 2003;290:2443-2454.