Learning from Pain Scales: Patient Perspective

PATRICIA CLARK, PILAR LAVIELLE, and HOMERO MARTÍNEZ

ABSTRACT.

Objective. Rheumatologists often deal with patients' pain, as commonly measured by clinical scales. However, no published study in the last 25 years has explored patient preferences for the 2 most frequently used clinical scales — the verbal rating scale (VRS) and the visual analog scale (VAS). We (1) evaluated patient preferences for the 10 cm horizontal VAS versus the 5 point VRS and identified associated reasons for their preferences; and (2) validated the test-retest reliability and construct validity of these scales.

Methods. Patients with painful rheumatological conditions rated the VAS and the VRS to assess pain intensity and stated which scale they preferred and why. Exploration of tender points and dolorimetry was performed in all cases.

Results. Of 113 patients in the sample, 93% were women, 85% of whom had rheumatoid arthritis. In this sample, 52.8% preferred the VRS, 28.3% the VAS, and 18.9% expressed no preference. Patients who preferred the VRS said it was easier than the VAS to understand and rate. They also reported being more comfortable using words than numbers. Patients who preferred the VAS said that numbers classified pain better and that this allowed them to be objective and precise. Patients with 0–6 years of schooling preferred the VRS, while those with > 6 years preferred the VAS. There was a significant association between the number of tender points and pain intensity with both scales, as well as between threshold and tolerance with the VAS. High correlations were found between the VAS and the VRS (r = 0.79) and between tolerance and threshold (r = 0.96). Test-retest showed a high correlation for both scales: VAS = 0.97 and VRS = 0.89.

Conclusion. Both scales are valid measures of pain intensity. The choice should depend on the setting, the clinician's goal, and the patient's level of education. Patient preference is central to better physician-patient communication. (J Rheumatol 2003;30:1584-8)

Key Indexing Terms:

PAIN
PAIN SCALES
PATIENT PREFERENCE
DOLORIMETRY
ARTHRITIS

---

From the Clinical Epidemiology Unit, Hospital de Especialidades, Centro Médico Nacional Siglo XXI, Instituto Mexicano del Seguro Social, Hospital General de México, OD, Mexico City, Mexico.

Supported by a grant from CONACYT (Grant 29169-M) to Dr. Patricia Clark.

P. Clark, MD, MSc, Clinical Epidemiology Unit, Hospital de Especialidades Bernardo Sepúlveda and Faculty of Medicine, Universidad Nacional Autónoma de México; P. Lavielle, MSc, Clinical Epidemiology Unit, Hospital de Especialidades Bernardo Sepúlveda Centro Medico Nacional Siglo XXI IMMS, Hospital General de México; H. Martínez, MD, PhD, Head, Medical Research Council, Centro Medico Nacional Siglo XXI IMMS.

Address reprint requests to Dr. P. Clark, Blvd. Virreyes 1010, Lomas de Chapultepec, CP 11000, Mexico City. E-mail: pclark@att.net.mx

Submitted November 19, 2001; revision accepted December 5, 2002.

---