Obese and non-obese individuals with knee osteoarthritis: Association of quantitative sensory testing with the presence of drug-drug interaction, body composition, and physical function - A cross-sectional and prospective study

Abstract

Obesity is among the main comorbidities present in individuals with knee osteoarthritis (KOA). These conditions, respected or not, tend to present reduced physical function, resulting from changes in their body composition, factors that can influence a significant increase in musculoskeletal pain. Pain is the main complaint of these individuals. Thus, the use of drugs for their relief, added to the use of drugs for coexisting chronic diseases, can lead to medication, thus modifying pain processing. Thus, the aim of the present study is to analyze the association of quantitative sensory tests with the presence of drug interaction, body composition, and physical function between obese and non-obese subjects with KOA. 100 participants with KOA, with grades II, III, and IV (Kellgren & Lawrence) will be divided into 2 groups: (1) Obese (n=50), with BMI e 30, and (2) Non-obese (n=50), with a BMI < 30. All subjects will be submitted to bilateral inheritance x-rays and blood collection from the antecubital vein, for analysis of the lipid and glycemic profile. All subjects will answer tests to evaluate catastrophizing, kinesiophobia, KOA symptoms by WOMAC, and symptoms similar to neuropathic pain by NPSI. The use of medication for pain and other coexisting chronic diseases will be recorded using a specific instrument. The body composition of all participants will be evaluated by the Dual Energy X-Ray Absorptiometry (DXA) examination, and subsequently, physical function tests will be performed (30 seconds Sit and Stand, 40-meter quick walk and climb up and descend stairs, and assessment of pain related to physical activity). For quantitative pain analysis, Quantitative Sensory Tests (TSQ) will be performed in a standardized sequence: 1- Pressure pain threshold 2- Temporal summation of pain; and 3- Conditioned pain modulation. During the follow-up period, participants will receive a log book so that they can record the medications used, pain symptoms and physical activities performed during the study period on a weekly basis. For data analysis, descriptive analysis of the variables will be performed and the normality and homogeneity of variances will be verified. According to the data distribution, the corresponding independent or non-parametric t-test will be applied, especially for cross-sectional analyses. For the analysis of prospective data, mixed model ANOVA will be applied, if the data are parametric and repeated measures ANOVA for non-parametric data. Finally, a linear regression model will be performed for the dependent variable pain, including the other variables as independent. For all analyses, a significance level of 5% (p<0.05) will be adopted.