``` 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49``` ```*(Q) I would like syntax to calculate the Incremental AUC (area under the curve) ignoring the sub-baseline segments. * Numerical examples are given in http://www.fao.org/docrep/w8079e/w8079e0a.htm. * and in http://www.fao.org/docrep/w8079e/w8079e00.gif. *(A) Posted to SPSSX-L list by Raynald Levesque on 2002/06/19. * http://pages.infinit.net/rlevesqu/index.htm. * Next sample data come from the above web site. DATA LIST LIST /id meas0 meas15 meas30 meas45 meas60 meas90 meas120 iauc1 (9F8.1). BEGIN DATA 0 4.3 6.3 7.9 5.3 4.1 4.6 4.9 114 1 4 6 6.7 5.5 5.3 5 4.2 155 2 4.1 5.8 8 6.5 5.9 4.8 3.9 179 3 4 5 5.8 5.4 4.8 4.2 4.4 93 4 4.1 6.3 9 8.7 6.7 5.7 3.9 279 5 5 7.1 8.8 8 5.6 5.4 4.2 155 END DATA. LIST. * Set the time constants for the horizontal axis. DO REPEAT h = h0 h15 h30 h45 h60 h90 h120 / t = 0 15 30 45 60 90 120. COMPUTE h = t. END REPEAT. EXECUTE. * trapezoidal integration of glusose = f(time) curve . VECTOR time = h0 to h120. VECTOR gluc = meas0 to meas120 . COMPUTE iauc2 = 0. LOOP #k = 2 to 7. IF #k=2 inival = gluc(1). DO IF (NOT(MISSING(gluc(#k)))). COMPUTE minval=MIN(gluc(#k-1),gluc(#k)) - inival. COMPUTE maxval=MAX(gluc(#k-1),gluc(#k)) - inival. DO IF minval>0. COMPUTE iauc2 = iauc2 + (time(#k) - time(#k -1))*((gluc(#k -1) + gluc(#k))/2-inival) . ELSE IF maxval>0. COMPUTE iauc2 = iauc2 + (time(#k) - time(#k -1))*(maxval / (maxval - minval)*maxval/2) . END IF. END IF. END LOOP. * Clean up. MATCH FILES FILE=* /DROP=h0 h15 h30 h45 h60 h90 h120 minval maxval inival. EXECUTE. ```
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