抄録
The speed of change in pain intensity as measured by the visual analog scale (VAS) was investigated in patients with acute low back pain (LBP). Each patient was initially treated with oral nonsteroidal anti–inflammatory drugs (NSAIDs). Clinical outcome was determined by patient self–assessment on the day of the last visit and classified into four groups: healed, improved, marginal, and unidentified. Data were analyzed for 131 cases in the healed (n=55), improved (n=62), and marginal (n=14) groups. VAS values at the first and last visits were denoted as VAS–f and VAS–l, respectively. ∆VAS, the speed of change in the VAS value per day was calculated by dividing the change in the VAS value by the number of days elapsed. The initial ∆VAS (∆VAS–i) and the ∆VAS throughout the study (∆VAS–t) were calculated between the first and second visits and between the first and last visits, respectively. VAS–f was not relevant to outcome, while VAS–l was strongly correlated with outcome, as expected. Both ∆VAS–i and ∆VAS–t were significantly correlated with outcome. Patients in the healed and improved groups showed higher ∆VAS–i values as compared with those in the marginal group. A ∆VAS–i over 5 mm/day predicted favorable outcomes. The ∆VAS–i can be regarded as a predictor of outcome in acute LBP. Speedy pain relief should be planned for patients with acute LBP with a low ∆VAS–i to prevent a change to chronic LBP.
