Measurement properties of painDETECT by average pain severity

Abstract

BackgroundSince the burden of neuropathic pain (NeP) increases with pain severity, it is important to characterize and quantify pain severity when identifying NeP patients. This study evaluated whether painDETECT, a screening questionnaire to identify patients with NeP, can distinguish pain severity.Materials and methodsSubjects (n=614, 55.4% male, 71.8% white, mean age 55.5 years) with confirmed NeP were identified during office visits to US community-based physicians. The Brief Pain Inventory – Short Form stratified subjects by mild (score 0–3, n=110), moderate (score 4–6, n=297), and severe (score 7–10, n=207) average pain. Scores on the nine-item painDETECT (seven pain-symptom items, one pain-course item, one pain-irradiation item) range from −1 to 38 (worst NeP); the seven-item painDETECT scores (only pain symptoms) range from 0 to 35. The ability of painDETECT to discriminate average pain-severity levels, based on the average pain item from the Brief Pain Inventory – Short Form (0–10 scale), was evaluated using analysis of variance or covariance models to obtain unadjusted and adjusted (age, sex, race, ethnicity, time since NeP diagnosis, number of comorbidities) mean painDETECT scores. Cumulative distribution functions on painDETECT scores by average pain severity were compared (Kolmogorov–Smirnov test). Cronbach’s alpha assessed internal consistency reliability.ResultsUnadjusted mean scores were 15.2 for mild, 19.8 for moderate, and 24.0 for severe pain for the nine items, and 14.3, 18.6, and 22.7, respectively, for the seven items. Adjusted nine-item mean scores for mild, moderate, and severe pain were 17.3, 21.3, and 25.3, respectively; adjusted seven-item mean scores were 16.4, 20.1, and 24.0, respectively. All pair-wise comparisons of scores between pain-severity groups showed sizable and statistically significant differences (P<0.0001). Cumulative distribution functions showed distinct separation between severity (P<0.0001). Cronbach’s alphas were 0.76 and 0.80 for the nine- and seven-item scales, respectively.ConclusionThis study provides strong psychometric evidence on the validity and reliability of painDETECT for distinguishing average pain severity in patients with NeP.

A cross-sectional study examining the psychometric properties of the painDETECT measure in neuropathic pain

“…As previously shown, 18 corrected item-to-total correlations showed adequate item discrimination (≥0.4) for pain symptom items on the nine- and seven-item painDETECT versions, but the correlations were low (<0.3) for the two non-sensory items on the nine-item version. Similar to what was observed for the combined conditions, each of the NeP conditions showed adequate discrimination (≥0.4) for all pain symptom items on both versions of painDETECT, and most of the pain sensory items had slightly higher item-to-total correlations on the seven-item version relative to the nine-item version ( Table 4 ).…”

“…A previous analysis demonstrated the ability of painDETECT to discriminate among average pain severity levels, enhancing its ability to characterize NeP. 18 The results of the current analysis expand upon the measurement properties of painDETECT, and confirm that this instrument shows further evidence of validity and reliability useful for screening of NeP across a range of NeP conditions. Adjusted mean scores on painDETECT were of similar magnitude for each NeP condition and were within the range (≥19) considered indicative of a high probability of NeP, which would be expected in this population of patients with confirmed NeP diagnoses.…”

“…These higher values on the seven-item version relative to the nine-item version were also observed when painDETECT was evaluated for its ability to distinguish between pain severity levels. 18 Although both versions showed good psychometric properties, the consistently higher values on the seven-item version suggest that the nonsensory items may be more useful for characterizing NeP than screening for it.…”

“… 16 , 17 Data from this study were used to demonstrate the ability of painDETECT to discriminate among average pain severity levels of mild, moderate, and severe pain. 18 The same study also affords the opportunity to evaluate measurement properties of painDETECT across the six conditions overall and individually. Therefore, the objective of the present analysis was to garner evidence on similarities and differences between the nine-item and seven-item versions of the painDETECT measure for six different NeP conditions by psychometrically assessing the scoring, internal consistency reliability, and item-level discrimination of painDETECT for identifying NeP components.…”

Efficacy and tolerability balance of oxycodone/naloxone and tapentadol in chronic low back pain with a neuropathic component: a blinded end point analysis of randomly selected routine data from 12-week prospective open-label observations

“…The NC of these cLBP patients was evaluated using the modified seven-item version of the painDetect questionnaire (PDQ 7 ),52 and patients were required to have a PDQ 7 score of ≥11 at baseline (with scores of 11–18 classified as “mixed” and scores of 19–35 classified as “neuropathic”) to qualify their data set for this analysis.…”