Evaluation of sleep quality in subjects with chronic nononcologic pain

A survey conducted by the National Sleep Foundation found that 20% of Americans have sleep disorders and 45% experience chronic pain. Several authors evaluated the interrelationship between these functions using various instruments such the Pittsburgh Sleep Quality Index (PSQI) and identified that 34% of subjects in the general population have a poor quality of sleep, but there are few studies that assess the quality of sleep in patients with chronic pain of nonmalignant origin. We undertook this study to evaluate the quality of sleep using the PSQI in patients with chronic pain unrelated to cancer. We conducted a clinical, nonrandomized, uncontrolled, descriptive, and prospective study, applying the PSQI through a direct one-time interview to 311 subjects with chronic pain unrelated to cancer. According to the categorization of the PSQI between good and poor sleepers, 89% of the subjects were poor sleepers (n = 276). There are significant differences in pain intensity according to the categorization of the PSQI, with a higher intensity shown in the "poor sleepers" (analysis of variance [ANOVA], P = .030). Using a linear regression model to estimate the curve, a higher score is rated on the PSQI global score (ANOVA, P = .000, R(2) = .46) with the increase of the intensity of the pain. We conclude that "poor sleepers" or those who considered their sleep as "poor quality" have significantly higher pain intensity. This suggests that intensity of pain plays a role in evaluating the quality of sleep in the subjective perception of sleep and instruments that assess quality.