Influence of interpretation of pain scores on patients’ perception of pain: A prospective study

BACKGROUND AND AIMS: Assessment of pain using pain scales is essential. In the Numeric Rating Scale (NRS), patients are asked to score their pain intensity on a scale from 0 to 10 (10- worst pain). This requires some abstract thinking by the patient, also the pain scores (PS) may not essentially communicate the patients’ need for more analgesia. We planned a study to evaluate the change in patients’ self-assessed PS after understanding clinical interpretation of the NRS. METHODS: This prospective study was registered after approval from our hospital ethics board. Sample size estimated for the trial was 360 patients. All postoperative patients were recruited after informed consent. Patients having prolonged stay in Intensive Care Unit (more than 48 h), or those who underwent emergency surgeries were excluded. During Acute Pain Service (APS) rounds, patients were asked to rate their PS on the NRS. This was followed by a briefing about the clinical interpretation of the scale, and the patients were asked to re score their pain using the same scale. The change in pain severity was compared using Chi-square test. RESULTS: Following explanation, a change in severity was seen for PS at rest [X(2) (9, N- 360) = 441, P < 0.001] and at movement [X(2) (9, N- 360) = 508, P < 0.001]. Overall, a change in PS severity was seen in 162 patients (45%). A decrease and an increase in the severity of pain was seen in 119 and 41 patients respectively. CONCLUSION: Explaining the clinical interpretation of PS on a NRS does lead to a change in patients’ self-assessed PS.