Factors Associated with Increased Risk for Clinical Insomnia in Patients with Chronic Neck Pain.

BACKGROUND Insomnia is highly prevalent among people with chronic pain conditions. Because insomnia has been shown to worsen pain, mood, and physical functioning, it could negatively impact the clinical outcomes of patients with chronic pain. OBJECTIVE To determine the risk factors associated with clinical insomnia in chronic neck pain (CNP) patients. STUDY DESIGN Retrospective analysis. SETTING Outpatient department for interventional pain management at a university hospital. METHODS Data from 218 CNP patients were analyzed in this study. The Insomnia Severity Index (ISI) was used to determine the presence of clinical insomnia (ISI score ≥ 15). Patient demographics and pain-related factors were evaluated with logistic regression analysis to identify risk factors of clinical insomnia in CNP. RESULTS In total, 53.7% of patients reported mild to severe insomnia after neck pain development; 22.9% of patients met the criteria for clinically significant insomnia (ISI score ≥ 15). In multivariate analysis, high pain intensity, the presence of comorbid musculoskeletal pain, and a high level of depression were strongly associated with clinical insomnia in patients with CNP. Among these factors, a greater level of depression was the strongest predictor of clinical insomnia, with the highest odds ratio of 3.689 (95% CI 1.570-8.667). LIMITATIONS This study was conducted in a single clinical setting including a selected study population with a homogeneous racial background. The ISI does not include several sleep-related variables, the roles of which are unknown in determining insomnia severity. CONCLUSIONS Insomnia should be addressed as an indispensable part of pain management in CNP patients with these risk factors, especially depression. CLINICAL TRIAL This study is a retrospective analysis. IRB No: 4-2014-0801.