Chronic Pain Prevalence and Associated Factors in a Segment of the Population of Sao Paulo City

A cross-sectional epidemiologic survey was performed to determine the prevalence of chronic pain (CP) and to identify associated factors in a random sample of persons 15 years or older from a segment of the population of Sao Paulo City, Brazil. A total of 1,108 eligible participants were randomly selected, and face-to-face interviews were performed with 826 individuals (74.5%) between December 2011 and February 2012. Chronic Pain Grade, Hospital Anxiety and Depression Scale, and EuroQol-5D were used to verify pain characteristics and the associated signs of psychological distress. A prevalence of 42% (95% confidence interval, 38.6-45.4) was observed for CP, and the participants with CP had an average pain intensity of 5.9 (standard deviation = 1.9) and a pain-related disability of 4.1 (standard deviation = 3.2) on a 0 to 10 scale. Persistent pain was present in 68.6% of those with CP, and 32.8% of the population sample had high-intensity or high-interference pain (Chronic Pain Grade II, III, and IV). Quality of life was significantly worse among the CP individuals. The following factors were independently associated with CP: female gender, age 30 years or older, <= 4 years of education, symptoms consistent with anxiety, and intense physical strain. Indicators of pain severity increased with pain grades. Perspective: CP is highly prevalent in the city of Sao Paulo and has a considerable impact on health-related quality of life. Demographic, socioeconomic, and psychological factors are independently associated with this condition. (C) 2014 by the American Pain Society