Chronic back pain (CBP) is a worldwide public health problem. CBP generates negative impacts on the lives of individuals and costly expenses for the health system, including those directed at treatments for CBP. However, the impact of multimorbidity on the treatment of CBP is still unclear.

To identify the types of treatments commonly reported by adults with CBP with and without multimorbidity.

Cross-sectional study with data from Brazilian adults (≥18 year) who self-reported CBP (n=18930) in the National Health Survey 2019. Treatments for CBP were identified through the dichotomous yes/no answer: physical therapy; exercises regularly; uses medication or injections; makes use of acupuncture, medicinal plants and phytotherapy, homeopathy, meditation, yoga, tai chi chuan or some other integrative and complementary practice; and regular follow-up with a health professional. Descriptive statistics were reported and associations between the two groups were confirmed using adjusted logistic regression models and confidence intervals (95% CI). Sociodemographic variables such as age, sex, schooling, income and health insurance were used as covariates in the analysis.

Adults with CBP and multimorbidity (69.4%) had higher prevalence and association for physical therapy (14.2% vs.7.9%; adjusted OR (ORa)= 1.61, 95%CI: 1.33- 1.94), use of medication or injections (47.8% vs.36.5%; ORa= 1.38, 95%CI: 1.22-1.56), and follow-up with a health professional (29% vs. 17.5%; ORa= 1.51, 95%CI: 1.29-1.78) compared with adults without multimorbidity. There was no difference between groups for use of acupuncture, medicinal plants and phytotherapy, homeopathy, meditation, yoga, tai chi chuan or some other integrative and complementary practice and regular exercise due to CBP.

The study revealed that most adults with CBP do not undergo physical therapy or regular exercise, with the use of medication or injections being the most used intervention, especially among adults with multimorbidity. Health education strategies, encouraging the practice of regular exercise and greater access to physiotherapy are fundamental for changing this scenario.

The study reinforces the need for health education strategies, encouraging the practice of regular exercise and greater access to physical therapy.