[Patient perspectives in outcome research : Development of a focus group concept for collating patient perspectives on determination of effectiveness of multimodal pain therapy - A pilot study]

Validation of a core patient-reported-outcome measure set for operationalizing success in multimodal pain therapy: useful for depicting long-term success?

Background

The study aims to validate a previously developed and published combined success criterion for patients after multimodal pain therapy (Donath et al., BMC Health Serv Res 15:272, 2015). The criterion classifies treated patients as successful in the long term on the basis of pain severity, disability through pain, depressiveness, and health-related quality of life.

Methods

Routine longitudinal data of 135 pain patients treated with multimodal pain therapy in 2014–2015 at the Interdisciplinary Pain Center of the University Clinic Erlangen were available at baseline, therapy start, therapy end, and 12 months after treatment. Patients were, on average, 51.0 (SD 11.1) years old and to 63.7% female, two thirds were employed (66.7%). We conducted an analysis of concurrent validity (with: pain severity, disability through pain, depressiveness, mental and physical quality of life), criterion validity (with disability days, self-rated success), convergent validity (with stress, anxiety, well-being), and discriminant validity (with chronicity of pain, comorbidity), objectivity, and reliability. Statistically, descriptive and inference statistics, graphical methods and MANOVAs were used.

Results

Patients classified as successful had significantly better values on the 5 variables demonstrating concurrent validity (all p < .001), significantly fewer Disability days (M = 15.31 (SD = 23.15) vs. M = 26.75 (SD = 29.15)); t (133) = 2.308; p = .024, less Anxiety (Pillai-Spur: F (3, 131) = 2.972, p = .034), less Stress (Pillai-Spur: F (3, 131) = 9.907, p < .001), and better Well-being (Pillai-Spur: F (3, 131) = 9.594, p < .001) 12 months after treatment than patients classified as not successful. The Spearman correlation between success classification and Chronicity stage was .094 (p = .280).

Conclusion

We demonstrated the validity of the combined success criterion with long-term data in addition to confirming the reliability and objectivity of the criterion. Future research might consider identifying predictors of success in multi-modal pain therapy.

Electronic supplementary material

The online version of this article (10.1186/s12913-018-2911-6) contains supplementary material, which is available to authorized users.

[Patient first - The impact of characteristics of target populations on decisions about therapy effectiveness of complex interventions: Psychological variables to assess effectiveness in interdisciplinary multimodal pain therapy]

INTRODUCTION

The assessment of treatment effectiveness in public health settings is ensured by indicators that reflect the changes caused by specific interventions. These indicators are also applied in benchmarking systems. The selection of constructs should be guided by their relevance for affected patients (patient reported outcomes). The interdisciplinary multimodal pain therapy (IMPT) is a complex intervention based on a biopsychosocial understanding of chronic pain. For quality assurance purposes, psychological parameters (depression, general anxiety, health-related quality of life) are included in standardized therapy assessment in pain medicine (KEDOQ), which can also be used for comparative analyses in a benchmarking system. The aim of the present study was to investigate the relevance of depressive symptoms, general anxiety and mental quality of life in patients undergoing IMPT under real life conditions.

METHODS

In this retrospective, one-armed and exploratory observational study we used secondary data of a routine documentation of IMST in routine care, applying several variables of the German Pain Questionnaire and the facility's comprehensive basic documentation. 352 participants with IMPT (from 2006 to 2010) were included, and the follow-up was performed over two years with six assessments. Because of statistically heterogeneous characteristics a complex analysis consisting of factor and cluster analyses was applied to build subgroups. These subgroups were explored to identify differences in depressive symptoms (HADS-D), general anxiety (HADS-A), and mental quality of life (SF 36 PSK) at the time of therapy admission and their development estimated by means of effect sizes. Analyses were performed using SPSS 21.0®.

RESULTS

Six subgroups were derived and mainly proved to be clinically and psychologically normal, with the exception of one subgroup that consistently showed psychological impairment for all three parameters. The follow-up of the total study population revealed medium or large effects; changes in the subgroups were consistently caused by two subgroups, while the other four showed little or no change. In summary, only a small proportion of the target population (20 %) demonstrated clinically relevant scores in the psychological parameters applied.

DISCUSSION

When selecting indicators for quality assurance, the heterogeneity of the target populations as well as conceptual and methodological aspects should be considered. The characteristics of the parameters intended, along with clinical and personal relevance of indicators for patients, should be investigated by specific procedures such as patient surveys and statistical analyses.