Background

The the Brief Pain Inventory (BPI) measures the severity of pain and the degree to which the pain interferes with common activities of daily living. Pain severity questions are rated on a scale of 0 to 10, where 0 = ‘No pain’ and 10 = ‘Pain as bad as you can imagine’, with patients asked to rate their pain in four items including, average, worst and least pain over the last week, and their pain right now. Pain severity is then calculated as an average of these four items. Whereas the benchmark for average pain is based on the single average pain item only.

The interference questions are rated on a scale of 0 to 10, where 0 = ‘Does not interfere’ and 10 = ‘Completely interferes’. The interference subscale is an average of the seven interference questions. At least 4 of 7 questions must be completed for this subscale to be valid. The IMMPACT recommendation for assessment of clinically significant change on the BPI interference scale is a change of 1 point over the average of the 7 items.

Severity bands for these items are:
• 0-4 = mild pain
• 5-6 = moderate pain
• 7-10 = severe pain

The IMMPACT group’s recommendations for assessing clinical significance for 0-10 numeric pain scales are that a change of:
≥ 10% represents minimally important change
≥ 30% represents moderate clinically important change (ePPOC uses this category to identify clinically significant improvement for average and worst pain)
≥ 50% represents substantial clinically important change.

Pain severity

Pain interference

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