The relationship between chronic pain pattern, interference with life and health-related quality of life in a nationwide community sample.

To establish the scope of the problem of chronic pain in the population, we need to extend the focus on prevalence, the most frequently studied factor. Among other important factors is the complex relationship between the temporal characteristics of pain and their impact on peoples' lives. The purpose of the present study was to describe the characteristics of chronic pain, including pattern, severity, location, spread, and duration, in a population-based sample and to investigate the relationships between pain pattern and impact on the individual's life measured by interference with life and health-related quality of life (HRQoL). In this cross-sectional study, a postal questionnaire measuring pain characteristics, life interference (Brief Pain Inventory), and HRQoL (Short Form 36 Health Survey), was sent to a sample of 4,500 individuals, randomly drawn from the Icelandic National Register. The total response rate was 36.9% and was significantly higher among native Icelanders (40.6%) than individuals of non-Icelandic origin (8.6%).The prevalence of chronic pain (≥3 months) was 47.5% with mean duration of 9.3 years, and 31.9% reported constant pain. Participants with constant pain reported higher life interference scores and less HRQoL than participants with intermittent or periodic pain. Hierarchical stepwise regression analyses showed that pain pattern and severity accounted for 44.4% variance for life interference. The range of the variances for these variables for the five domains of HRQoL was from 7.3% (mental health) to 53.3% (bodily pain). Pain pattern and severity are the most significant predictors of the impact of chronic pain on individual's daily life.