Prevalence of Thai People with Lumbar Instability and Associated Factors: A Cross-Sectional Study

BACKGROUND: Lumbar instability has been extensively reported; however, the risk factors for lumbar instability remain poorly defined, and understanding this condition better would help health professionals and their patients. PROPOSAL: To determine the prevalence of lumbar instability in Thai people with chronic low back pain (CLBP) and explore the factors associated with lumbar instability in these patients. PATIENTS AND METHODS: Using multistage random sampling methods, 1762 participants with CLBP were enrolled in the study from six regions of Thailand. Data were collected using a paper-based questionnaire. Participants were interviewed by physical therapists in the hospital they attended. They were classified as having lumbar instability when they attained ≥7/14 items on the lumbar instability screening tool. Univariate and multivariate regression analysese were used to determine the possible factors associated with lumbar instability. RESULTS: There were 961 (54.54%) participants with lumbar instability and 801 (45.46%) participants without. The eight factors associated with lumbar instability were: (i) age ≥40 years (AOR: 1.36; 95% CI: 1.09–1.69); (ii) body mass index ≥25 kg/m(2) (AOR: 1.42; 95% CI: 1.16–1.74); (iii) having an underlying disease (AOR: 1.32; 95% CI: 1.06–1.65); (iv) frequent lifting ≥5 kg in occupational habits (AOR: 1.69; 95% CI: 1.36–2.09); (v) prolonged walking ≥4 hours per day (AOR: 1.31; 95% CI: 1.04–1.64); (vi) gardening in leisure time (AOR: 1.37; 95% CI: 1.10–1.71); (vii) other area of pain (AOR: 1.24; 95% CI: 1.01–2.52): and (viii) other area of numbness (AOR: 1.85; 95% CI: 1.50–2.27). When considering only women, prior pregnancy was associated with lumbar instability with OR of 1.76 (95% CI: 1.36–2.22), p-value <0.0001. CONCLUSION: When treating patients with CLBP who are suspected to have lumbar instability, healthcare professionals should consider associated factors that might be modifiable targets for interventions to improve outcomes.