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Table 2 Anchor-based method to determine the minimal important difference of the HADS

From: The minimal important difference of the hospital anxiety and depression scale in patients with chronic obstructive pulmonary disease

  Regression equation Corresponding to 0.5 change in CRQ score (95% confidence interval*)
Change in HADS 0.73 + 1.35*CRQemotional function, r2 = 0.30 1.41 (1.18–1.63)
anxiety score 1.04 + 1.05*CRQmastery, r2 = 0.26 1.57 (1.37–1.76)
Change in HADS total score 1.07 + 1.21*CRQemotional function, r2 = 0.31 1.68 (1.48–1.87)
  1.00 + 1.20*CRQtotal, R2 = 0.26 1.60 (1.38–1.82)
  1. Constant and coefficients correlations multiplied by -1 to facilitate interpretation.
  2. * The 95% confidence intervals around the minimal important difference should not be used to make treatment decisions or develop trials without the understanding that the point estimate is the best estimate of the minimal important difference and that the limits of the 95% confidence intervals are sample size dependent. Since this sample is relatively small, the 95% confidence intervals are wide and, thus, attention must be paid to this issue. The point estimate should be used as best estimate.