Published in:
01-10-2007 | Original Article
Accuracy of the Pain Numeric Rating Scale as a Screening Test in Primary Care
Published in: Journal of General Internal Medicine | Issue 10/2007
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BACKGROUND
Universal pain screening with a 0–10 pain intensity numeric rating scale (NRS) has been widely implemented in primary care.
OBJECTIVE
To evaluate the accuracy of the NRS as a screening test to identify primary care patients with clinically important pain.
DESIGN
Prospective diagnostic accuracy study
PARTICIPANTS
275 adult clinic patients were enrolled from September 2005 to March 2006.
MEASUREMENTS
We operationalized clinically important pain using two alternate definitions: (1) pain that interferes with functioning (Brief Pain Inventory interference scale ≥ 5) and (2) pain that motivates a physician visit (patient-reported reason for the visit).
RESULTS
22% of patients reported a pain symptom as the main reason for the visit. The most common pain locations were lower extremity (21%) and back/neck (18%). The area under the receiver operator characteristic curve for the NRS as a test for pain that interferes with functioning was 0.76, indicating fair accuracy. A pain screening NRS score of 1 was 69% sensitive (95% CI 60–78) for pain that interferes with functioning. Multilevel likelihood ratios for scores of 0, 1–3, 4–6, and 7–10 were 0.39 (0.29–0.53), 0.99 (0.38–2.60), 2.67 (1.56–4.57), and 5.60 (3.06–10.26), respectively. Results were similar when NRS scores were evaluated against the alternate definition of clinically important pain (pain that motivates a physician visit).
CONCLUSIONS
The most commonly used measure for pain screening may have only modest accuracy for identifying patients with clinically important pain in primary care. Further research is needed to evaluate whether pain screening improves patient outcomes in primary care.