Accuracy of the pain numeric rating scale as a screening test in primary care.
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.


METHODS
Prospective diagnostic accuracy study


METHODS
275 adult clinic patients were enrolled from September 2005 to March 2006.


METHODS
We operationalized clinically important pain using two alternate definitions: (1) pain that interferes with functioning (Brief Pain Inventory interference scale > or = 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.
Center on Implementing Evidence-Based Practice, Roudebush Veterans Affairs Medical Center, Indianapolis, IN, USA. krebse@iupui.edu
Erin E
EE
Krebs
Timothy S
TS
Carey
Morris
M
Weinberger
D000328:Adult; D000367:Age Factors; D000368:Aged; D002908:Chronic Disease; D015331:Cohort Studies; D016001:Confidence Intervals; D005260:Female; D006801:Humans; D008297:Male; D008403:Mass Screening / Q000592:standards*; D008875:Middle Aged; D010146:Pain / Q000175:diagnosis*; D010147:Pain Measurement / Q000592:standards*; D011320:Primary Health Care / Q000592:standards*; D011336:Probability; D011446:Prospective Studies; D012372:ROC Curve; D012307:Risk Factors; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D012737:Sex Factors