Table 4.
Performance characteristics of LASSO to classify patients with dementia using primary care electronic medical record notes written before and after dementia case ascertainment in Ontario, Canada
| Days relative to index* | F1 score | Sens | Spec | PPV | NPV | E50 | E90 | EMax | ICI |
|---|---|---|---|---|---|---|---|---|---|
| Before index date | |||||||||
| − 730 | 12.2 | 6.9 | 99.9 | 54.6 | 98.9 | 0.008 | 0.01 | 0.56 | 0.01 |
| − 365 | 18.8 | 11.5 | 99.9 | 55.4 | 99.0 | 0.007 | 0.01 | 0.49 | 0.01 |
| − 120 | 26.6 | 18.3 | 99.8 | 54.2 | 99.0 | – | – | – | – |
| − 60 | 28.6 | 19.9 | 99.8 | 54.9 | 99.0 | – | – | – | – |
| − 30 | 20.1 | 13.2 | 99.8 | 52.0 | 98.7 | – | – | – | – |
| − 14 | 23.1 | 15.0 | 99.8 | 57.6 | 98.6 | – | – | – | – |
| − 7 | 29.4 | 19.3 | 99.9 | 70.2 | 98.6 | 0.003 | 0.01 | 0.998 | 0.01 |
| After index date | |||||||||
| 0 | 14.4 | 8.3 | 99.9 | 65.0 | 98.9 | 0.008 | 0.01 | 0.44 | 0.01 |
| + 7 | 34.5 | 24.3 | 99.8 | 60.0 | 99.1 | 0.01 | 0.01 | 0.26 | 0.01 |
| + 14 | 34.4 | 24.0 | 99.8 | 62.2 | 99.1 | 0.01 | 0.01 | 0.23 | 0.01 |
| + 30 | 40.7 | 31.4 | 99.8 | 61.7 | 99.2 | 0.01 | 0.01 | 0.26 | 0.01 |
| + 60 | 46.5 | 36.7 | 99.8 | 67.6 | 99.3 | 0.01 | 0.01 | 0.23 | 0.01 |
| + 120 | 54.6 | 44.7 | 99.8 | 71.8 | 99.3 | 0.001 | 0.003 | 0.21 | 0.004 |
| + 365 | 62.8 | 53.8 | 99.8 | 77.7 | 99.5 | 0.002 | 0.003 | 0.21 | 0.005 |
| + 730 | 71.8 | 66.2 | 99.8 | 78.8 | 99.6 | 0.001 | 0.003 | 0.23 | 0.004 |
Key: Sens sensitivity; Spec specificity; PPV positive predictive value; NPV negative predictive value; F1 score harmonic mean of sensitivity and PPV; “–” value could not be estimated
*Patients’ index dates represent the date of dementia case ascertainment for patients with dementia or the date of the latest note in the EMR for patients without dementia. For dates prior to index, only notes taken from the prespecified date to the index date were included (e.g., 730 days prior to the index date to but not including the index date). For dates after index, all notes from the first note in the EMR to the prespecified date after the index date were included (e.g., first note in the EMR to 730 days after the index date)