Study Highlights

• Included were consecutive patients presenting to 1 outpatient clinic who consented to completing a face-to-face interview after the clinician visit.
• Excluded were patients who did not speak English.
• As a routine, the NRS was completed with the vital signs for all patients, and a nurse documented the answers in the electronic medical record.
• Patients with an NRS score of 1 or higher were oversampled for analysis.
• 20% of the sample had an NRS score of 0.
• Participants were interviewed after the clinician visit.
• Nursing notes, dictated physician notes, and problem lists were abstracted from the medical records after the interview.
• The BPI was administered.
• The BPI measures 7 domains: general activity, mood, walking ability, normal work, relationships with other people, sleep, and enjoyment of life.
• Possible BPI scores ranged from 0 ("does not interfere") to 10 ("interferes completely"), and a lead-in question was used to define pain as other than "everyday pains such as minor headaches, sprains, and toothaches."
• 2 questions were used to elicit the reason for the visit: "What is the main reason for your visit?" and "What other concerns would you like to talk to your doctor about today?"
• Responses were classified as pain symptom, nonpain symptom, or other.
• Because there is no criterion standard definition of clinically important pain, the investigators operationalized the definition as pain that interferes with functioning and pain that motivates a clinician visit.
• A score of 5 or greater on the BPI interference scale was used as the reference standard for pain interfering with function.
• The ROC curves for the NRS were compared with the reference standards for function and motivation.
• Of 548 patients approached, 357 consented and 77% were included in the analysis.
• Mean age of the patients was 55 years, each patient had an average of 1.9 conditions, 80% saw their regular physician, and 46% saw a resident physician.
• 40% of patients reported a pain symptom as the reason for the visit, with 22% reporting the pain as a primary and 18% as a secondary concern.
• Among participants with an NRS screening score of 1 or greater, the mean score was 6.0.
• Most patients reported musculoskeletal pain, with the most common locations in the lower extremity (21%) and back or neck (18%).
• 55% of patients overall and 77% with at least 1 pain symptom reported persistent pain for 6 months or longer.
• The area under the ROC curve for the NRS vs the BPI (for a score of ≥ 5) was 0.76.
• The lowest possible cut-off point (an NRS score of 1) was 69% sensitive and 78% specific for functional interference.
• Thus, nearly one third of patients with pain-related functional interference had an NRS score of 0.
• At the NRS score of 4, sensitivity was 64% and specificity was 83%.
• If the pretest probability of pain-related functional interference was 40%, the post-test probabilities corresponding to scores of 0, 1 to 3, 4 to 6, and 7 to 10 would be 21%, 40%, 64%, and 79%, respectively.
• The area under the ROC curve for the NRS vs the motivation for a clinician visit was 0.78.
• 21% of patients who reported pain as the primary reason for the visit and 28% of those who reported pain as any reason for the visit had a NRS score of 0.
• The sensitivity of an NRS score of 1 was 71%, and the specificity was 81%.
• An NRS score of 4 had a sensitivity of 63% and a specificity of 83%.
• The study authors concluded that the NRS had only moderate accuracy for identifying patients with clinically important pain.