Prevalence and social burden of active chronic low back pain in the adult Portuguese population: results from a national survey.

To determine the prevalence of active chronic low back pain (CLBP) in the adult Portuguese population; to compare the active CLBP population with the population without CLBP; and to explore factors associated with active CLBP. The present study was conducted under the scope of EpiReumaPt a population-based study. Active CLBP was self-reported and considered if present on the day of the interview and for ≥90 days. Prevalence estimates were calculated. Association of active CLBP with quality of life, functional ability and healthcare consumption were evaluated. Factors associated with active CLBP were identified through logistic regression. Among 10.661 EpiReumaPt subjects, 1487 self-reported active CLBP. The prevalence of active CLBP was 10.4 % (95 % CI 9.6; 11.9 %). After adjustment, active CLBP subjects had a higher likelihood for anxiety symptoms (OR 2.77), early retirement due to disease (OR 1.88) and more physician visits (β = 2.65). Factors significantly and independently associated with the presence of active CLBP were: female gender (OR 1.34), overweight/obesity (OR 1.27), presence of self-reported rheumatic musculoskeletal disease (RMD) (OR 2.93), anxiety symptoms (OR 2.67), age (OR 1.02) and higher number of self-reported comorbidities (OR 1.12). Active CLBP is highly prevalent in the Portuguese population and is associated with disability and with a high consumption of healthcare resources. Female gender, older age, anxiety symptoms, overweight/obesity, the presence of other RMD and the number of comorbidities were independently associated with the presence of active CLBP. These factors should be taken into account when new cohort prospective studies will be developed.