Figure 1.
Generation of the patient–feature matrix.
(1) The workflow downloads ∼5.6 M strings from the 22 clinically relevant ontologies as well as trigger terms from NegEx and ConText for negation detection. (2) It uses term frequency and syntactic type information (e.g., predominant noun phrases) from MedLine to prune the set of strings into a clean lexicon, and (3) then applies the lexicon directly against the textual clinical notes using exact string matching. (4) The workflow furthermore uses NegEx and ConText rules to filter negated terms and terms within family history contexts. (5) Next, UMLS and BioPortal mappings and semantic type information are used to normalize terms into concepts, which are furthermore grouped into the semantic groups “drug”, “disease”, “device”, or “procedure”. (6) Finally, the annotations of the clinical notes are used to construct the patient–feature matrix, where each row of the matrix represents a patient and the columns are the clinical concepts annotated in the patients clinical notes; here the time stamps of the clinical notes induce a temporal ordering of the annotations over the entire patient–feature matrix.
Table 1.
Peripheral artery disease definition.
Table 2.
Balance in variables before and after propensity score matching in STRIDE.
Figure 2.
Outcomes in PAD patients taking Cilostazol compared to the matched control group.
Odds ratios and 95% confidence intervals are plotted; upper limits of the confidence intervals are clipped at 4. There are no statistically significant differences in major adverse cardiovascular events (A), there is an increased risk for several major adverse limb events (B), and there are no differences for arrhythmias and arrhythmic symptoms (C). MACE and MALE are pooled variables combining all other variables listed below.
Figure 3.
Outcome analysis in the CHF subgroup comparing patients with a history of CHF and taking Cilostazol to a matched control of CHF patients not taking Cilostazol.
Odds ratios and 95% confidence intervals are plotted; upper limits of the confidence intervals are clipped at 4. There is no statistically increased risk for any major adverse cardiovascular events (A), there is an increased odds ratio for several major adverse limb events (B), and there are no differences for arrhythmias and arrhythmic symptoms (C). MACE and MALE are pooled variables combining all other variables listed below.
Table 3.
Outcomes in the CHF-subgroup in the PAMF dataset comparing Cilostazol patients with their matched controls.