The following is a summary of “Comparison of measures of pain Intensity during Sickle cell disease Vaso-occlusive episodes,” published in the August 2024 issue of Pain by Knisely et al.

Researchers conducted a retrospective study to analyze the minimal clinically significant difference (MCID) in pain severity and agreement between the visual analog scale (VAS) and the verbal numeric rating scale (NRS) in patients with sickle cell experiencing an acute vaso-occlusive episode in the emergency department (ED). 

They observed participants administered the VAS (0-100), NRS (0-100), and descriptor scale every 30 minutes while in the ED, 100 participants (mean age 30.2 years; 61% female) data was analyzed by calculating the mean differences, 95% CI between current and preceding scores when the participant reported a little worse or a little better pain for each scale (255 VAS and 150 NRS observations) to assess the MCID for the VAS & NRS. Pearson correlation and the Bland-Altmann method measured 411 paired VAS & NRS observations. 

The results showed  MCID 8.77 mm (95% CI: 7.43 mm to 10.83 mm) for VAS and 8.29 (95% CI: 6.47 to 11.60) for NRS. The VAS and NRS scales were highly correlated, with a coefficient of 0.88 (P< 0.001). The Bland-Altman analysis showed a mean difference of -4.6 ± 1.96, with 95% limits of agreement ranging from -20 to 29. Despite the high correlation, there was substantial variability in agreement between the VAS and NRS scales, suggesting they are not interchangeable for assessing pain during a vaso-occlusive event.

They concluded the average MCID for pain severity during a vaso-occlusive event (VOE) in individuals with sickle cell disease, as measured by VAS (8.77 mm), was lower than previously reported. The MCID for NRS was 8.29, and the agreement between the VAS and NRS was assessed, indicating that these scales cannot be used interchangeably to measure pain intensity in sickle cell disease.

Source: jpain.org/article/S1526-5900(24)00613-8/abstract#%20