Effects of Mattress Firmness on Pain in Patients With Chronic Low-Back Pain

A Latin-Square Crossover Study of the Effects of Mattress Firmness on Pain in Patients With Chronic Low-Back Pain

The primary study objective is to determine whether mattress firmness affects pain in patients with chronic low-back pain. We hypothesize that mattresses that differ in their firmness and support should have a varying effect on low-back pain patients' level of pain and pain-related disability. We also seek to test the hypothesis that the optimal mattress might vary from person to person.

In this regard, we will test:

1. Whether there is a single mattress that is superior to the others in terms of reducing low-back pain and pain related disability.
2. Whether the optimal mattress for reducing pain varies in the observed population.

Few treatments are effective for chronic low-back pain, a disorder that causes marked social costs in developed countries. A "comfortable" mattress is commonly assumed to play an essential role, both on a preventive and on a therapeutic basis on chronic low-back pain. However, evidence supporting the beneficial effects of different levels of mattress support on pain is lacking.

The primary study objective is to determine whether mattress firmness affects pain in patients with chronic low-back pain. We hypothesize that mattresses that differ in their firmness and support should have a varying effects on LBP patients' level of pain and pain-related disability. We also seek to test the hypothesis that the optimal mattress might vary from person to person. In this regard, we will test:

1. whether there is a single mattress that is superior to the others in terms of reducing low-back pain and pain-related disability and
2. whether the optimal mattress for reducing pain varies in the observed population.

The secondary objectives are:

1. to determine whether there is a relationship between mattress firmness and sleep in this population;
2. to determine whether there is a relationship between pain and sleep in this population;
3. to determine whether key sleep variables (subjective or objective) are mediating or moderating factors of the relationship between mattress and level of low-back pain (LBP) and disability;
4. to determine if different sleep surfaces have differential effects on measures of daily function among patients with chronic LBP;
5. to evaluate if Kingsdown's proprietary algorithm for selecting optimal mattress "fits" with the subject's best mattress for reducing pain and improving sleep and measures of daytime functioning;
6. to conduct exploratory regression analyses using variables included in the proprietary algorithm and other demographics and measures of physical characteristics to predict the optimal "fit" mattress (i.e., the mattress associated with lowest morning pain ratings, best sleep measures and optimal levels of daytime function);
7. to determine if different sleep surfaces have differential effects on measures of partner sleep disturbance;
8. to determine if there is a relationship between partner pain level and partner sleep disturbances.

Please see "Eligibility Criteria" for inclusion and exclusion information.

Inclusion Criteria:

• Low back pain location must be inferior to T12 and superior to the gluteal fold and chronic (greater than 3 months)
• Patient Global Impression for Pain of at least 3 on a 1-5 scale (moderate severity)
• Visual Analog Scale for Pain of at least 40 on a 100 point scale (0 = no pain; 100 = worst pain)
• Presence of normal motor strength on exam
• English speaking and reading man/woman between the ages of 21-64

Exclusion Criteria:

• Neurologic or medical illness that is directly responsible for back pain
• Psychiatric disease
• Back related surgery
• Substance abuse
• Pregnancy (self or partner)
• Sleep-affecting medications
• Recent surgery
• Recent physical trauma
• Fibromyalgia
• Spinal Stenosis
• Sciatica
• Spondylolisthesis
• Spondyloarthropathy
• Sciatica
• Spinal Stenosis
• Vertebral Fractures
• Rheumatoid Arthritis
• Inability to comply
• Untreated sleep disorders
• Night-shift worker
• Frequent travel
• Parent of child under 2
• Pending litigation for pain issue
• Corticosteroid use in the last 90 days