How much does the Dallas Pain Questionnaire score have to improve to indicate that patients with chronic low back pain feel better or well?

PURPOSE: The Dallas Pain Questionnaire (DPQ) assesses the impact of low back pain (LBP) on four components (0-100) of daily life. We estimated the minimal clinically important improvement (MCII) and the patient acceptable symptom state (PASS) values of DPQ in LBP patients. METHODS: 142 patients with LBP lasting for at least 4 weeks completed a battery of questionnaires at baseline and 6 months later. Questions for MCII addressed patient-reported response to treatment at 6 months on a five-point Likert scale, while a yes/no question concerning satisfaction with present state was used to determine PASS. MCII was computed as the difference in mean DPQ scores between patients reporting treatment as effective vs. patients reporting treatment as not effective, and PASS was computed as the third quartile of the DPQ score among patients who reported being satisfied with their present state. RESULTS: MCII values were 22, 23, 2 and 10 for daily activities, work and leisure, social interest, and anxiety/depression, respectively. PASS values were 29, 23, 20 and 21 for the four components, respectively. The PASS total score threshold of 24 correctly classified 84.1 % of the patients who reported being unsatisfied with their present state, and 74.7 % of patients reported being satisfied. CONCLUSIONS: These values give information of paramount importance for clinicians in interpreting change in DPQ values over time. Authors should be encouraged to report the percentage of patients who reach MCII and PASS values in randomized clinical trials and cohort studies to help clinicians to interpret clinical results.

Core Outcome Measure Index for low back patients: do we miss anxiety and depression?

PURPOSE: The Core Outcome Measure Index (COMI) is a multidimensional questionnaire that investigates five dimensions in low back pain (LBP) patients, but does not address the psychological dimension. As the biopsychosocial perspective is recognized as important to capture the entire clinical picture of these patients, this multicenter prospective cohort study was designed to investigate the psychometric properties of a modified version of the COMI (COMIAD) which included 2 additional items, exploring anxiety and depression, respectively. METHODS: 168 subacute or chronic LBP patients recruited in spine clinics completed a set of questionnaires before and after treatment (follow-up at 6 months). Construct validity was explored by comparing each item of the COMIAD to validated full-length questionnaires. Thus two additional questionnaires were included to assess the construct validity of the anxiety and depression measures. The psychometric properties of the COMI and COMIAD were then compared. RESULTS: The two new items showed good internal consistency, high correlations with the corresponding full-length questionnaires, no floor or ceiling effect and good reproducibility (test-retest agreement kappa 0.68 for anxiety, 0.62 for depression). The addition of the 2 items did not alter internal validity (Cronbach's alpha = 0.88 and 0.87, respectively). The smallest detectable difference, the Minimal Clinically Important Improvement and the Patient Acceptable Symptom State were only minimally affected by the changes. CONCLUSION: The questions exploring anxiety and depression have good intrinsic and psychometric capacities (i.e., no floor or ceiling effects and high correlations with full-length scales) and did not significantly modify the psychometrics of the original COMI questionnaire. The COMIAD offers the possibility to include the psychological dimension in the multidimensional evaluation without significantly affecting questionnaire length.