Study design: This is a structured, evidence-based review of all available studies addressing the concept of nonorganic findings: Waddell signs (WSs).
Objectives: To determine what evidence, if any, exists for the various interpretations for the presence of WSs on physical examination.
Summary of background data: WSs are a group of eight physical findings divided into five categories, the presence of which has been alleged at times to have the following interpretations: Malingering/secondary gain, hysteria, psychological distress, magnified presentation, abnormal illness behavior, abnormal pain behavior, and somatic amplification. At the present time, there is, therefore, significant confusion as to what these findings mean.
Methods: A computer and manual literature search produced 61 studies and case series reports relating to WSs. These references were reviewed in detail, sorted, and placed into tabular form according to the following subject areas: 1) Reliability (test-retest); 2) Reliability (inter-rater); 3) Reliability (factor analysis); 4) Validity, psychological distress; 5) Validity, correlation Minnesota Multiphasic Pain Inventory (MMPI); 6) Validity, correlation abnormal illness behavior; 7) Validity, other behaviors; 8) Validity, as a nonorganic phenomenon; 9) Validity, correlation pain drawing; 10) Validity, functional performance; 11) Validity, treatment outcome; 12) Validity, predicting surgical treatment outcome; 13) Validity, return to work outcome; 14) Validity, secondary gain correlation; and 15) Validity, pain correlation. Each study in each topic area was classified according to the type of study it represented according to the type of evidence guidelines developed by the Agency for Health Care Policy and Research (AHCPR). In addition, a list of 14 study quality criteria was used to measure the quality of each study. Each study was categorized for each criterion as positive, (criterion filled), negative (criterion not filled), or not applicable independently by two of the authors. A percent quality score was obtained for each study by counting the total number of positives obtained, dividing by 14 minus the total number of not applicables, and multiplying by 100. Only studies having a quality score of 75% or greater were used to formulate the conclusions of this review. The strength and consistency of the evidence represented by the remaining studies in each topic area (above) was then categorized according to the strength and consistency AHCPR guidelines. Conclusions of this review for each topic area are based on these results.
Results of data synthesis: Of the 61 studies, four had quality scores below 75% and were not used to generate the results of this review. According to the AHCPR guidelines for strength and consistency of the reviewed data, the following results were obtained: 1) There was consistent evidence for WSs being associated with decreased functional performance, poor nonsurgical treatment outcome, and greater levels of pain; 2) There was generally consistent evidence for WSs not being associated with psychological distress, abnormal illness behavior, or secondary gain; 3) There was also generally consistent evidence that WSs are an organic phenomenon and that they cannot be used to discriminate organic from nonorganic problems; 4) There was inconsistent evidence that WSs do demonstrate inter-rater reliability, do not correlate with the neurotic triad of the MMPI, are associated with poorer surgical treatment outcome, and are associated with nonreturn to work; 5) There was little or no evidence that WSs demonstrate test-retest reliability, or reliable factors, and are associated with self-esteem problems, catastrophizing, or the nonorganic pain drawing.
Conclusions: Based on the above results, the following conclusions were made: 1) WSs do not correlate with psychological distress; 2) WSs do not discriminate organic from nonorganic problems; 3) WSs may represent an organic phenomenon; 4) WSs are associated with poorer treatment outcome; 5) WSs are associated with greater pain levels; 6) WSs are not associated with secondary gain; and 7) As a group, WS studies demonstrate some methodological problems.