Chronic migraine (CM) is a highly prevalent neurological condition and a leading cause of disability, particularly among women. Pain assessment is crucial for managing this condition, and scales such as the Numerical Pain Scale (NPS), which evaluates pain on a scale from 0 to 10, and the Visual Analog Scale (VAS), consisting of a 100-mm line ranging from "no pain" to "worst possible pain," are widely used for this purpose.

To compare the VAS and NPS and correlate them with a functional disability scale in patients with chronic migraine.

This was a cross-sectional observational study with a non-probabilistic convenience sample. Subjects included were those diagnosed with CM by a neurologist, on stable CM medication for at least three months, and without other associated headaches. Pain levels were assessed using the VAS, NPS, and the Migraine Disability Assessment Scale (MIDAS). Upon inclusion, participants were asked, "What is the intensity of your headache during a migraine attack?", which was quantified using the NPS. Next, the second part of the assessment was conducted, where the MIDAS and VAS were applied. Data were analyzed descriptively and inferentially using SPSS software, version 20. The Kolmogorov-Smirnov test was used to assess data normality; the Wilcoxon test was applied to compare NPS and VAS scores; and Spearman’s correlation was used to evaluate the relationship between the variables and the MIDAS scale. A 95% confidence interval and a p-value < 0.05 were considered statistically significant.

The sample comprised 80 women, with a mean age of 35.99 ± 2.17 years. The median NPS pain score was 10 (2.00), while the median VAS score was 8.35 (2.78). The MIDAS median score was 81.5 (88.75), indicating a significant functional impact of migraine. A statistically significant difference (p < 0.05) was observed in the comparison between the scales, with a positive correlation (rS = 0.27; p < 0.05). The NPS showed a stronger correlation with the MIDAS scale (rS = 0.33; p < 0.01) compared to the VAS (rS = 0.27; p < 0.05), though both correlations were significant.

The NPS demonstrated a stronger correlation with pain-related functional impairment, suggesting it may be a more sensitive tool for this purpose.

The stronger correlation between the NPS and MIDAS suggests that the NPS may be more effective in monitoring the impact of pain on patients&apos; functionality, aiding in therapeutic decision-making. Further studies are needed to confirm these findings and expand the understanding of the clinical applicability of pain assessment scales.