Predicting treatment outcomes of pain patients attending tertiary multidisciplinary pain treatment centers: A pain trajectory approach.

Background: Though multidisciplinary pain treatment (MPT) is considered the gold standard for managing chronic pain, it is unclear which patients benefit most from this high-cost treatment approach. Aims: The goals were to identify subgroups of patients sharing similar pain severity trajectories over time and predictors of MPT responsiveness. Methods: Participants were 1894 patients (mean age = 53.18 years [SD = 14.0]; female = 60.3%) enrolled in the Quebec Pain Registry with moderate to severe baseline pain severity. Patients completed validated questionnaires on pain and related constructs before initiating treatment and 6, 12, and 24 months later. Results: Trajectory analyses of pain severity (intensity and interference) showed that a three-class model best fit the data. Two of the trajectories, which included 24.5% of patients, showed significant improvement in pain severity levels over time (improvers). Compared to patients in the nonimproving trajectory (non-improvers), improvers were younger and more likely to suffer from neuropathic pain and had pain of shorter duration, lower worst pain intensity, lower sleep disturbances and depression scores at baseline, a lower tendency to catastrophize, and better physical health-related quality of life (QOL). This predictive model had a specificity of 96.2% and a sensitivity of 23.6%. Conclusions: Only a minority of patients exhibited an improvement in their pain severity with MPT. Several patients' characteristics were significantly associated with pain trajectory membership. Early identification of nonimprovers, through examination of baseline characteristics and rates of change in pain scores, can provide valuable information about prognosis and open the doors for evaluation of different cost-effective treatment approaches. Abbreviations: CP = chronic pain; MPT = multidisciplinary pain treatment; QPR = Quebec Pain Registry; QOL = quality of life.

Distinguishing problematic from nonproblematic postsurgical pain: a pain trajectory analysis after total knee arthroplasty.

The goal of this study was to follow a cohort of patients undergoing total knee arthroplasty over time to: (1) identify and describe the various pain trajectories beginning preoperatively and for up to 12 months after surgery, (2) identify baseline predictors of trajectory group membership, and (3) identify trajectory groups associated with poor psychosocial outcomes 12 months after surgery. One hundred seventy-three participants (female = 85 [49%]; mean age [years] = 62.9, SD = 6.8) completed pain and psychological questionnaires and functional performance tests preoperatively and 4 days, 6 weeks, and 3 and 12 months after total knee arthroplasty. Using growth mixture modeling, results showed that a 4-group model, with a quadratic slope and baseline pain data predicting trajectory group membership, best fit the data (Akaike information criterion = 2772.27). The first 3 pain trajectories represent various rates of recovery ending with relatively low levels of pain 12 months after surgery. Group 4, the constant high pain group, comprises patients who have a neutral or positive pain slope and do not show improvement in their pain experience over the first year after surgery. This model suggests that preoperative pain levels are predictive of pain trajectory group membership and moderate preoperative pain, as opposed to low or high pain, is a risk factor for a neutral or positive pain trajectory postoperatively. Consistent with previous studies, these results show that postoperative pain is not a homogeneous condition and point to the importance of examining intraindividual pain fluctuations as they relate to pain interventions and prevention strategies.

Validation of the Reintegration to Normal Living Index for community-dwelling persons with chronic spinal cord injury.

OBJECTIVE: To determine the validity (construct, concurrent) of the Reintegration to Normal Living (RNL) Index for measurement of community participation in adults with chronic spinal cord injury (SCI). DESIGN: Cross-sectional telephone survey. SETTING: Rehabilitation institute. PARTICIPANTS: Community-dwelling adult men and women (N=617) with SCI who were at least 1 year postinjury. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: RNL Index and Satisfaction With Life Scale (SWLS). RESULTS: Reliability of the RNL Index was determined by using Cronbach α, and construct validity was established through confirmatory factor analysis (CFA). In addition, general linear models to predict RNL Index scores were conducted to establish concurrent validity. The RNL Index is a reliable measure of community participation (α=.87). CFA analyses suggested that the RNL Index loads onto a 2-factor solution and is distinct from the SWLS. Significant predictors of RNL Index score included years post-injury, impairment, ambulatory status, employment, and poor health, which yielded R(2)=.26 (P<.001). CONCLUSIONS: The RNL Index is a valid and reliable measure of community participation for persons with chronic SCI of traumatic cause.