Syndemic and syndemogenesis of low back pain in Latin-American population: a network and cluster analysis.

INTRODUCTION: Although low back pain (LBP) is a high-impact health condition, its burden has not been examined from the syndemic perspective. OBJECTIVE: To compare and assess clinical, socioeconomic, and geographic factors associated with LBP prevalence in low-income and upper-middle-income countries using syndemic and syndemogenesis frameworks based on network and cluster analyses. METHODS: Analyses were performed by adopting network and cluster design, whereby interrelations among the individual and social variables and their combinations were established. The required data was sourced from the databases pertaining to the six Latin-American countries. RESULTS: Database searches yielded a sample of 55,724 individuals (mean age 43.38 years, SD = 17.93), 24.12% of whom were indigenous, and 60.61% were women. The diagnosed with LBP comprised 6.59% of the total population. Network analysis showed higher relationship individuals' variables such as comorbidities, unhealthy habits, low educational level, living in rural areas, and indigenous status were found to be significantly associated with LBP. Cluster analysis showed significant association between LBP prevalence and social variables (e.g. Gender inequality Index, Human Development Index, Income Inequality). CONCLUSIONS: LBP is a highly prevalent condition in Latin-American populations with a high impact on the quality of life of young adults. It is particularly debilitating for women, indigenous individuals, and those with low educational level, and is further exacerbated by the presence of comorbidities, especially those in the mental health domain. Thus, the study findings demonstrate that syndemic and syndemogenesis have the potential to widen the health inequities stemming from LBP in vulnerable populations. Key points • Syndemic and syndemogenesis evidence health disparities in Latin-American populations, documenting the complexity of suffering from a disease such as low back pain that is associated with comorbidities, unhealthy habits, and the social and regional context where they live. • The use of network and cluster analyses are useful tools for documenting the complexity and the multifaceted impact in health in large populations as well as the differences between countries. • The variability and impact of socioeconomic indicators (e.g., Gini index) related to low back pain and comorbidities could be felt through the use of cluster analysis, which generates evidence of regional inequality in Latin America. • Populations can be studied from different models (network and cluster analysis) and grouping, presenting new interpretations beyond geographical groupings, such as syndemic and inequity in health.

Comparison of an interferon-gamma assay with tuberculin skin testing for detection of tuberculosis (TB) infection in patients with rheumatoid arthritis in a TB-endemic population.

OBJECTIVE: Tuberculosis (TB) in patients with rheumatoid arthritis (RA) undergoing treatment with anti-tumor necrosis factor (TNF) agents is commonly the result of reactivation of latent TB infection (LTBI); detection and treatment of LTBI is essential before treatment with anti-TNF agents. We reported previously that the tuberculin skin test (TST) is inaccurate for diagnosis of LTBI in patients with RA. Here, we compare the prevalence of LTBI in RA patients and matched controls according to positive TST and QuantiFeron-TB Gold In-Tube version (QFT) results and determine their agreement. METHODS: A cross-sectional study of 101 RA patients and 93 controls was conducted in Lima, Perú, where the prevalence of LTBI in the general population has been estimated to be 68%. Blood was drawn for QFT assay followed by TST using 2-TU of RT 23 purified protein derivative. TST was deemed positive at >or= 5 mm for RA patients and >or= 10 mm for controls. RESULTS: There were no significant differences between RA patients and controls for age, sex, bacillus Calmette-Guérin vaccination, or history of or contact with TB. 88% of patients had active RA disease and 2 (1.9%) patients had indeterminate QFT results. The number of subjects testing positive with the QuantiFeron assay was comparable between patients and controls (44.6% vs 59.1%, respectively), whereas the TST detected significantly less LTBI among RA patients (26.7%) than controls (65.6%). Thus, the rate of LTBI in RA patients represented 75% and 41% of the rate in their controls using QFT or TST, respectively (p = 0.008). Poor agreement between TST and QFT was seen in RA patients, but in controls, good agreement was observed between these tests. CONCLUSION: In a TB-endemic population, the QuantiFeron-TB Gold In-Tube assay seemed to be a more accurate test for detection of LTBI in RA patients compared with the TST, and may potentially improve the targeting of prophylactic therapy before treatment with anti-TNF agents.