The Clinical Importance of Changes in the 0 to 10 Numeric Rating Scale for Worst, Least, and Average Pain Intensity: Analyses of Data from Clinical Trials of Duloxetine in Pain Disorders

JOURNAL OF PAIN

卷:11

Article

Farrar, John T.¹  Pritchett, Yili L.²  Robinson, Michael³  Prakash, Apurva⁴  Chappell, Amy⁴ 

[1] Univ Penn, Sch Med, Dept Biostat & Epidemiol, Philadelphia, PA 19041 USA

[2] Global Pharmaceut R&D, Abbott Labs, Abbott Pk, IL USA

[3] Lilly USA LLC, Indianapolis, IN USA

[4] Eli Lilly & Co, Lilly Res Labs, Indianapolis, IN 46285 USA

关键词: Duloxetine;    fibromyalgia;    diabetic peripheral neuropathic pain;    pain measurement;    standards;   

DOI  :  10.1016/j.jpain.2009.06.007

来源: Elsevier

【 摘 要 】

Data on 1,700 patients pooled from 5 randomized, placebo-controlled duloxetine studies (3 in diabetic peripheral neuropathic pain and 2 in fibromyalgia) were analyzed to determine clinically important differences (CIDs) in the 0 to 10 Numeric Rating Scale-Pain Intensity (NRS-PI) for patient-reported worst and least pain intensity while validating the previously published level for average pain. The correspondence between the baseline-to-endpoint raw and percentage change in the NRS-PI for the worst, least, and average pain were compared to patients' perceived improvements at endpoint as measured by the 7-point Patient Global Impression of Improvement (PGI-I) scales. Stratification by baseline pain separated the raw but not the percent change scores. The PGI-I category of much better or above was our a priori definition of a CID. Cutoff points for the NRS-PI change scores were determined using a receiver operator curve analysis. A consistent relationship between the worst and average NRS-PI percent change and the PGI-I was demonstrated regardless of the study, pain type, age, sex, or treatment group with a reduction of approximately 34%. The least pain item CID was slightly higher at 41%. Raw change CID cutoff points were approximately 2, 2.5 and 3 for least, average, and worst pain respectively. Perspective: We determined an anchor-based value for the change in the worst, least, and average pain intensity items of the Brief Pain Inventory that best represents a clinically important difference. Our findings support a standard definition of a clinically important difference in clinical trials of chronic-pain therapies. (C) 2010 by the American Pain Society

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