An observational study of agreement between percentage pain reduction calculated from visual analog or numerical rating scales versus that reported by parturients during labor epidural analgesia

E Pratici; S Nebout; N Merbai; J Filippova; D Hajage; H Keita

doi:10.1016/j.ijoa.2017.02.001

An observational study of agreement between percentage pain reduction calculated from visual analog or numerical rating scales versus that reported by parturients during labor epidural analgesia

Int J Obstet Anesth. 2017 May:30:39-43. doi: 10.1016/j.ijoa.2017.02.001. Epub 2017 Feb 10.

Authors

E Pratici¹, S Nebout¹, N Merbai¹, J Filippova¹, D Hajage², H Keita³

Affiliations

¹ Service d'Anesthésie, CHU Louis Mourier, AP-HP, Université Paris 7, Paris, France.
² Unité de Recherche Clinique - GH HUPNVS - Site Louis Mourier, AP-HP, Université Paris, Paris, France.
³ Service d'Anesthésie, CHU Louis Mourier, AP-HP, Université Paris 7, Paris, France; Université Paris Diderot, Sorbonne Paris Cité, EA Recherche Clinique Coordonnée Ville-Hôpital, Méthodologies et Société (REMES), Paris, France. Electronic address: hawa.keita@aphp.fr.

PMID: 28284462
DOI: 10.1016/j.ijoa.2017.02.001

Abstract

Background: This study aimed to determine the level of agreement between calculated percentage pain reduction, derived from visual analog or numerical rating scales, and patient-reported percentage pain reduction in patients having labor epidural analgesia.

Methods: In a prospective observational study, parturients were asked to rate their pain intensity on a visual analog scale and numerical rating scale, before and 30min after initiation of epidural analgesia. The percentage pain reduction 30min after epidural analgesia was calculated by the formula: 100×(score before epidural analgesia-score 30min after epidural analgesia)/score before epidural analgesia. To evaluate agreement between calculated percentage pain reduction and patient-reported percentage pain reduction, we computed the concordance correlation coefficient and performed Bland-Altman analysis.

Results: Ninety-seven women in labor were enrolled in the study, most of whom were nulliparous, with a singleton fetus and in spontaneous labor. The concordance correlation coefficient with patient-reported percentage pain reduction was 0.76 (95% CI 0.6 to 0.8) and 0.77 (95% CI 0.6 to 0.8) for the visual analog and numerical rating scale, respectively. The Bland-Altman mean difference between calculated percentage pain reduction and patient-reported percentage pain reduction for the visual analog and numerical rating scales was -2.0% (limits of agreement at 29.8%) and 0 (limits of agreement at 28.2%), respectively.

Conclusion: The agreement between calculated percentage pain reduction from a visual analog or numerical rating scale and patient-reported percentage pain reduction in the context of labor epidural analgesia was moderate. The difference could range up to 30%. Patient-reported percentage pain reduction has advantages as a measurement tool for assessing pain management for childbirth but differences compared with other assessment methods should be taken into account.

Keywords: Concordance correlation coefficient; Epidural analgesia; Labor pain; Pain scales.

Publication types

Comparative Study
Observational Study

MeSH terms

Adult
Analgesia, Epidural / methods*
Analgesia, Obstetrical / methods*
Delivery, Obstetric
Female
Humans
Labor, Obstetric
Pain Measurement / methods*
Pregnancy
Prospective Studies
Reproducibility of Results