Analysis of the Numeric Rating Scale (NRS) Used in Clinical Studies Based on Randomized Controlled Studies

Abstract

Objectives: The purpose of this study was to review the status of numeric rating scale (NRS) usage and suggest the potential for use in multicenter retrospective studies of various diseases.Methods: Articles published from 2011 to 2021 that used the keywords “NRS", “Multi-center", and “RCT" were identified in foreign databases, including EMBASE, PubMed, CENTRAL. The articles were analyzed according to their use of "NRS" by symptoms and by disease group using the major classifications of the Korean Standard Classification of Diseases (KCD-7).Results: Classification by symptom in a total of 288 articles illustrates that the NRS was not only commonly used in pain evaluation but also for non-pain symptoms. In usage with non-pain symptoms, chief complaint of patients was the most common at 79%, and other factors included treatment satisfaction, evaluation of daily life, and sleep quality. In disease classification according to the KCD-7, the NRS was commonly used in connection with musculoskeletal and connective tissue diseases but was also utilized in various other disease groups.Conclusions: This study confirms usage of the NRS in multi-center RCTs, as the NRS was widely used in all types of diseases and symptoms. Considering the result and the advantages of the NRS, it is recommended for use as a daily evaluation tool for the collection of common data in multicenter retrospective studies.