External validation of a COPD prediction model using population-based primary care data: a nested case-control study Bright I Nwaru,1,2 Colin R Simpson,1 Aziz Sheikh,1,3 Daniel Kotz,1,3,4* 1
Asthma UK Centre for Applied Research, Centre for Medical Informatics, Usher Institute of Population Health Sciences, The University of Edinburgh, UK 2
School of Health Sciences, University of Tampere, Finland
3
Department of Family Medicine, CAPHRI School for Public Health and Primary Care, Maastricht University Medical Centre, Maastricht, The Netherlands 4
Institute of General Practice, Medical Faculty of the Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany
Correspondence: Prof. Dr. Daniel Kotz Institute of General Practice Medical Faculty of the Heinrich-Heine-University Moorenstr. 5 40225 Düsseldorf, Germany Email:
[email protected] Tel: 0049-211-81-16019 Web: www.daniel-kotz.de
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Supplementary File 1: External validation of a COPD prediction model using population-based primary care data: a nested case-control study Read codes used to define smoking status Read code and definition 1372: Trivial smoker - < 1 cig/day$$$ 1374: Moderate smoker - 10-19 cigs/d$$$ 1376: Very heavy smoker - 40+cigs/d$$$ 137G: Trying to give up smoking$$$ 137J: Cigar smoker$$$ 137P: Cigarette smoker$$$ 137R: Current smoker$$$ 137X: Cigarette consumption$$$ 137Z: Tobacco consumption NOS$$$ 137b: Ready to stop smoking$$$ 137d: Not interested in stopping smoking$$$ 137f: Reason for restarting smoking$$$ 137h: Minutes from waking to first tobacco consumption$$$ 1373: Light smoker - 1-9 cigs/day$$$ 1375: Heavy smoker - 20-39 cigs/day$$$ 137C: Keeps trying to stop smoking$$$ 137H: Pipe smoker$$$ 137M: Rolls own cigarettes$$$ 137Q: Smoking started$$$ 137V: Smoking reduced$$$ 137Y: Cigar consumption$$$ 137a: Pipe tobacco consumption$$$ 137c: Thinking about stopping smoking$$$ 137e: Smoking restarted$$$ 137g: Cigarette pack-years$$$ 1377: Ex-trivial smoker (= 0 100.00% >= .31 98.41% >= .47 96.29% >= .65 94.30% >= .93 92.34% >= 1.21 90.66% >= 1.52 90.43% >= 1.68 90.22% >= 1.86 89.99% >= 1.90 89.83% >= 2.14 76.24% >= 2.21 76.08% >= 2.37 58.47% >= 2.55 42.26% >= 2.83 23.41% >= 3.12 5.35% >= 3.43 4.56% >= 3.59 3.37% >= 3.77 2.36% >= 4.05 1.10% > 4.05 0.00% *PI=Prognostic index
Specificity 0.00% 9.34% 19.03% 27.02% 34.18% 39.39% 39.54% 39.65% 39.76% 39.84% 51.20% 51.28% 64.78% 76.53% 88.49% 99.09% 99.28% 99.47% 99.72% 99.87% 100.00%
Correctly classified 50.01% 53.89% 57.67% 60.67% 63.27% 65.03% 64.99% 64.94% 64.88% 64.84% 63.72% 63.68% 61.62% 59.39% 55.94% 52.21% 51.91% 51.41% 51.03% 50.47% 49.99%
Negative likelihood ratio 1,00 1,09 1,19 1,29 1,40 1,50 1,50 1,49 1,49 1,49 1,56 1,56 1,66 1,80 2,03 5,85 6,34 6,33 8,32 8,29
Positive likelihood ratio 0,17 0,19 0,21 0,22 0,24 0,24 0,25 0,25 0,26 0,46 0,47 0,64 0,75 0,87 0,96 0,96 0,97 0,98 0,99 1,00
Cut-point on PI* >= 0 >= .22 >= .49 >= .67 >= .95 >= 1.02 >= 1.25 >= 1.52 >= 1.69 >= 1.97 >= 2.26 >= 2.48 >= 2.76 >= 2.93 >= 3.21 >= 3.29 >= 3.51 >= 3.79 >= 3.95 >= 4.23 > 4.23
FEMALES Sensitivity 100.00% 97.30% 93.92% 90.97% 87.97% 85.23% 84.77% 84.24% 83.64% 83.08% 82.67% 73.05% 59.07% 45.06% 27.06% 8.28% 7.31% 5.84% 4.20% 2.23% 0.00%
Specificity 0.00% 12.02% 25.94% 37.66% 47.90% 56.31% 56.52% 56.89% 57.22% 57.50% 57.74% 64.01% 72.56% 80.55% 89.40% 98.72% 98.89% 99.17% 99.45% 99.69% 100.00%
Correctly classified 50.01% 54.67% 59.94% 64.32% 67.94% 70.77% 70.65% 70.56% 70.43% 70.30% 70.21% 68.53% 65.81% 62.80% 58.22% 53.49% 53.09% 52.50% 51.81% 50.95% 49.99%
Negative likelihood ratio 1,00 1,11 1,27 1,46 1,69 1,95 1,95 1,95 1,96 1,96 1,96 2,03 2,15 2,32 2,55 6,47 6,57 7,08 7,59 7,19
Positive likelihood ratio 0,22 0,23 0,24 0,25 0,26 0,27 0,28 0,29 0,29 0,30 0,42 0,56 0,68 0,82 0,93 0,94 0,95 0,96 0,98 1,00
Prognostic scores derived from the CPRD data
0.50 0.25 0.00
Sensitivity
0.75
1.00
Supplementary File 5:
0.00
0.25
0.50 1 - Specificity
0.75
1.00
Area under ROC curve = 0.7363
Figure S1 ROC curves for the prognostic scores derived using solely the CPRD data
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Prognostic scores derived from the CPRD data
0.50 0.25 0.00
Sensitivity
0.75
1.00
Supplementary File 5:
0.00
0.25
0.50 1 - Specificity
0.75
1.00
Area under ROC curve = 0.7363
Figure S1 ROC curves for the prognostic scores derived using solely the CPRD data
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