Abstract
BackgroundChiropractic Maintenance Care (MC) has been found to be effective for patients classified as dysfunctional (high pain severity, marked interference with everyday life due to pain, high affective distress, low perception of life control, and low activity levels) by the Swedish equivalent of the West Haven-Yale Multidimensional Pain Inventory (MPI-S). Although displaying good psychometric properties such as validity and reliability, the instrument was not designed to be used in clinical practice to screen patients for stratified care pathways. To effectively be able to screen for individuals suitable for MC, the aim was to develop a clinical instrument with the intent of identifying dysfunctional patients with acceptable sensitivity, specificity, and discriminant ability.MethodsData from 249 patients with a complete MPI dataset from an RCT that investigated the effect and cost-effectiveness of MC with a 12-month follow-up was used in this cross-sectional analysis. The MPI’s data was used to develop a short screening instrument to identify dysfunctional patients, with a summary measure, based on the original instrument. Different cutoffs were considered with regards to sensitivity, specificity, and discriminant ability and compared to the original instrument’s classification of dysfunctional patients. The instrument was then tested in 3 other existing datasets to assess validity across populations.ResultsUsing an explorative approach, the MAINTAIN instrument with 10 questions (0-6 Likert responses) with 5 dimensions (pain severity, interference, life control, affective distress, and support) was developed, generating an algorithm-based score ranging from -12 to 48. Reporting a MAINTAIN score of 18 or higher, 146 out of the 249 patients were classified as dysfunctional with 95.8% sensitivity and 64.3% specificity. At a score of 22 or higher, 109/249 were classified as dysfunctional with 81.1% sensitivity and 79.2% specificity. Discriminant ability (area under the curve (AUC)) was estimated to 0.87 (95% CI: 0.83, 0.92; p <0.001) and Youden’s index was highest (0.70) at a score of 20. The discriminant ability is similar and acceptable across populations with minor differences in optimal thresholds for identifying dysfunctional individuals.ConclusionThe MAINTAIN instrument had an acceptable performance with regards to identifying dysfunctional patients and may be used as a decision aid in clinical practice. By using 2 thresholds, patients can be categorized into “low probability (-12 to 17)”, “moderate probability (18 to 21)”, and “high probability (22 to 48)” of having a good outcome from maintenance care for Low Back Pain (LBP).Trial registrationClinical trials.gov; NCT01539863; registered February 28, 2012; https://clinicaltrials.gov/ct2/show/NCT01539863