Effect of firmness of mattress on chronic non-specific low-back pain: randomised, double-blind, controlled, multicentre trial

A firm mattress is commonly believed to be beneficial for low-back pain, although evidence supporting this recommendation is lacking. We assessed the effect of different firmnesses of mattresses on the clinical course of patients with chronic non-specific low-back pain. In a randomised, double-blind, controlled, multicentre trial, we assessed 313 adults who had chronic non-specific low-back pain, but no referred pain, who complained of backache while lying in bed and on rising. Mattress firmness is rated on a scale developed by the European Committee for Standardisation. The Hs scale starts at 1·0 (firmest) and stops at 10·0 (softest). We randomly assigned participants firm mattresses (Hs=2·3) or medium- firm mattresses (Hs=5·6). We did clinical assessments at baseline and at 90 days. Primary endpoints were improvements in pain while lying in bed, pain on rising, and disability. At 90 days, patients with medium-firm mattresses had better outcomes for pain in bed (odds ratio 2·36 [95% Cl 1·13–4·93]), pain on rising (1·93 [0·97–3·86]), and disability (2·10 [1·24–3·56]) than did patients with firm mattresses. Throughout the study period, patients with medium-firm mattresses also had less daytime low-back pain (p=0·059), pain while lying in bed (p=0·064), and pain on rising (p=0·008) than did patients with firm mattresses. A mattress of medium firmness improves pain and disability among patients with chronic non-specific low- back pain.