These CHMs are prescribed by licensed and experienced traditional Chinese medicine doctors in Taiwan, and they are served as traditional Chinese medicine in health care systems in Taiwan. CHMs include single herbs and herbal formulae. A single herb is made from the flower, root, stem, or leaf of a given plant. It is also made from an organ of an animal, insect, or mineral source. The herbal formulae are mixtures of a minimum of two single herbs. The CHM composition, frequency, and usage patterns are shown in
Supplementary Table S1. CHMs are produced by pharmaceutical Good Manufacturing Practice companies with in Taiwan.
Association rule mining was performed, as previously described, using SAS software (version 9.4; SAS Institute, Cary, NC, United States). This association rule mining has been applied to discover studies in the relationships of these CHM prescriptions (Chen et al., 2014 (
link); Cheng et al., 2019b (
link); Tsai et al., 2019 (
link)). Chinese herbal medicine (CHM) product X (CHM_X) and CHM product Y (CHM_Y) were shown as the “items,” respectively. The CHM prescriptions were used as the “transactions,” with co-occurrences of CHM_X and CHM_Y (
Table 3). This expression shows the relationship between the occurrences of CHM_X and CHM_Y. The strength of the association using this technique was expressed as support, confidence, and lift. Support is a measure of whether an association between CHM_X and CHM_Y happened by chance. The support (X) (%) value is the calculated joint probability of having both of CHM_X and CHM_Y, which is (the frequency of CHM_X and CHM_Y/total number of prescription) × 100%. Confidence is an indicator of how often CHM_Y appeared in transactions that contained CHM_X. The confidence value (CHM_X → CHM_Y; %) is the calculated conditional probability of having a prescription of CHM_Y among those who already have the prescription of CHM_X, which is given as (frequency of CHM_X and CHM_Y/frequency of CHM_X) x 100%. Lift is the ratio of observed support to expected support when X and Y are independent. The lift value is the confidence (CHM_X → CHM_Y) (%)/P (Y) (%) or confidence (CHM_Y → CHM_X) (%)/P (X) (%). A lift value greater than 1 indicates that the occurrences between the two CHM products are dependent and suggests a strong co-occurrence relationship between CHM_X and CHM_Y.
Network analysis was performed as previously described (Cheng et al., 2019a (
link); Cheng et al., 2019b (
link)) (
Figure 3). The single herb is expressed as a green circle, and the herbal formula is shown as a red circle. The prescription frequency of the single herb or herbal formula is shown (
Supplementary Table S2) and is denoted as the circle size. The support value (%) (between CHM_X and CHM_Y) is shown in
Table 3 and is expressed as the line size. The lift value is also shown in
Table 3 and is represented as the line color. The connection strength between the paired CHM products is shown as the line size and line color. All data were employed using Cytoscape software (
https://cytoscape.org/, version 3.7.0).