The frequency of sleep disturbances was found to be significantly higher in patients with CLBP, suggesting a significant association between both of them.

Chronic low back pain (CLBP) patients might suffer from sleep disorders. Adequate sleep hygiene is essential for the normal functioning of the body. Sleep disorders bring psychological and physiological changes in the body, which in the long-term may lead to serious health problems like hypertension, diabetes, coronary artery disease (CAD) and obesity. The pain restricted below the 12th rib and over inferior folds of the gluteal area posteriorly in the absence or presence of leg pain is termed as LBP. CLBP is when LBP lasts for more than three months. The cause of more than 90% of LBP cases remains unidentified (non-specific LBP) while the remaining 10% is associated with some pathological reason. Almost 20% of people may experience LBP at some point of time in their life.

The lifetime incidence of LBP has been estimated to be around 80%. The physically exerting jobs like heavy-weight lifting, whole body-vibration, lousy posture, forward bending and some psychosocial exertions like low control and high demand may exaggerate the LBP. All this significantly impacts work-related QoL and causes overall disability and depression. The understanding of the mechanism and management of CLBP has gained worldwide attention over the past few years. The percentage of LBP patients reporting sleep disturbances has been increasing at a drastic rate. The research indicates that inadequate sleep results in decreased mental capacity to endure pain. There have been few assumptions that sleep improvement may aid in better pain control. CLBP patients have arousal disturbance in brain waves at the time of sleep and during wake-up unrested.  LBP may cause structural and functional changes in the peripheral as well as the central nervous system known to adjust sleep and pain. There is still a great necessity to explore various exciting features of CLBP and sleep disorder.

Rationale behind research: Irrespective of the numerous studies depicting the positive association between LBP and sleep disorders, there is still a lack of concrete evidence regarding the same. 

Objective: The present study was conducted with two objectives:

• to estimate the frequency of sleep disturbances in patients with LBP
• to explore the association between self-reported functional disabilities and sleep disorder in CLBP patients

Study Outcomes:

• Severity of sleep disorder: This was estimated using the insomnia severity index (ISI). The seven enquires regarding sleep were included; upkeep of rest, the onset of sleep, degree of fulfilment with present sleep pattern, interference of sleep in the day to day functioning, worried about sleep disturbances and perceptible to others in relations of affecting the quality of life. 5-point Likert scale was used for scoring each factor from 0 to 4. The scores range from 0 to 28; where 0-7 means no clinically significant insomnia, 8-14 signifies sub-threshold insomnia, 15-21 means moderate severity insomnia and 22-28 signifies insomnia of severe nature.

• Functional disability: This was assessed using RMDQ, which contained 24 questions with total score=24. A score of less than 15 indicated low-level disability while a score of more than 15 stated the high-level disability.

Outcomes:

• The mean functional disability score was found to be 13.66±2.44. Eighty-four patients were found to have a sleep disorder (78 had sub threshold insomnia, and 6 had moderately severe clinical insomnia).

• A positive intermediate correlation was found between functional disability and sleep disorder. There was a moderate, but linear increase noted in the correlation, suggesting a significant association between sleep disturbance and functional disability in CLBP patients.

The present study demonstrated a significantly high level of sleep disturbances in CLBP patients. Also, the study reported a positive association between functional disability and sleep disturbances.

The researchers found that 70% of patients had non-specific CLBP, while 33% of patients found to have discogenic cause. The findings of this study are not in lines with the previous research study. The contradictory findings may also be a result of their sample size, a greater number of females and higher mean age. The incidence of sleep disorder reported in the present study was less than reported in the previous research, mainly due to lower mean age, different gender majority and use of varying outcome tool.

In the present study, the mean ISI score was 8.89, which is comparable to the previously reported values. Previous research has indicated a weak relationship between sleep disturbances and CLBP while our study reported a significant positive association. The earlier study has used the Pittsburgh Sleep Quality Index (PSQI) for assessing sleep disturbances while the present study utilized ISI tool. Overall results recommend a strong association between RMDQ and ISI in CLBP patients, but there could be other factors influencing the severity of sleep disorders. Further research with a larger sample size is needed to evaluate other causes and factors affecting sleep disturbances in CLBP patients.