title: Skew-symmetric Random Effect Models with Application to a Preventive Cohort Study: Improving Outcomes in Low Back Pain Patients.
abstract: BACKGROUND
  To investigate the respective contribution of various biologic and psychosocial factors, especially Health Related Quality of Life (HRQOL) as a main outcome, in the natural history of acute low back pain (LBP) and to evaluate the impact of this condition on HRQOL.
  
  
  METHODS
  In a prospective cohort study For 24 weeks, 150 patients were assessed at an outpatient clinic in Korea consulting for low back and confirmed disc herniation duration at inclusion and treated with treatment package comprised of herbal medicines, acupuncture, bee venom acupuncture, and a Korean version of spinal manipulation (Chuna). Study participants were evaluated at baseline and every 4 weeks for 24 weeks. Low back intensity levels were measured on a visual analog scale (0-10), back function was evaluated with the Oswestry Disability Index (0-100), disability assessed by HRQOL assessed by the short form 36 health survey (0-100 in 8 different sub-categories).
  
  
  RESULTS
  Out of 150 patients, 128 completed the 24 weeks of traditional therapy. Patients reported improvements SF-36 outcome measures. At the completion of the study, low back pain scores improved by a mean of 3.3 (95% CI = 2.8 to 3.8). According to the results of our modeling, low back intensity level, back function and BMI measures had significant effects on quality of life during study. Interpreting the coefficients of modeling, the impact of the decreasing acute LBP episode on HRQOL by VAS and ODI outcomes, was high and important.
  
  
  CONCLUSIONS
  This study highlights the large contribution of integrative package therapy as an effective preventive method for improving LBP patient's HRQOL.
authors.affiliation: Department of Biostatistics and Epidemiology, Health School, and Child Growth and Development Research Center, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Marjan
authors.initials: M
authors.lastname: Mansourian
authors.forename: Zahra
authors.initials: Z
authors.lastname: Mahdiyeh
authors.forename: Jongbae J
authors.initials: JJ
authors.lastname: Park
authors.forename: Shaghayegh
authors.initials: S
authors.lastname: Haghjooyejavanmard
keywords: Low back pain; health related quality of life; oswestry disability index