Background: Pain is costly and a major reason for seeking medical care. Our aim was to assess the proportion of people experiencing pain, and the severity of pain, at randomly selected times in a representative sample of individuals in the USA.
Methods: A community-based telephone survey was designed that attempted to contact about 10 700 individuals by random-digit dialling. After collecting diary information for one 24-h period, ratings of pain on a 0-6 anchored scale for three randomly selected 15-min intervals of the day were obtained. Outcome measures were the proportion of intervals with non-zero pain, the proportion of intervals with pain above 3 (the scale midpoint), and the average pain rating. Activities of those individuals who reported substantial pain were also examined. To make the results representative of the US population, sample data were adjusted with sample weights developed by the Gallup Organisation.
Findings: 3982 individuals were interviewed (response rate 37%). After adjustment for weighting, 28.8% of men and 26.6% of women reported feeling some pain at sampled times. Those with lower income or less education spent a higher proportion of time in pain and reported higher average pain than did those with higher income or more education. The average pain rating increased with age, although it reached a plateau between the ages of about 45 years and 75 years, with little difference between men and women. Satisfaction with life or health and the pain indicators tended to move in opposite directions.
Interpretation: The diary-survey methods described here could be used to study pain at the population level, and will enable the combination of pain assessments with information about activities of daily living.