Table 2.
Comparison of electronically defined new users of an antidepressant medication versus manual review of medical records
| Classification | Electronically defined (N) | Manual medical records abstraction (N) | PPV (95% CI) | ||
|---|---|---|---|---|---|
| New AD user | Prevalent AD user | No AD prescription | |||
| Total | 198 | 161 | 36 | 1 | 81.3 (76.4 to 87.0) |
| Standardized dose ratio ≤1.0 | 165 | 150 | 15 | 0 | 90.9 (85.5 to 94.4) |
| Expanded time windows* (years) | |||||
| 1 | 180 | 147 | 32 | 1 | 81.7 (75.4 to 86.6) |
| 1.5 | 167 | 138 | 28 | 1 | 82.6 (76.2 to 87.6) |
| 2 | 160 | 132 | 27 | 1 | 82.5 (75.9 to 87.6) |
| Olmsted County residence >1 year† | 192 | 155 | 36 | 1 | 81.3 (74.6 to 85.7) |
| By sex‡ | |||||
| Male | 98 | 77 | 21 | 0 | 78.6 (69.5 to 85.5) |
| Female | 100 | 84 | 15 | 1 | 84.0 (75.6 to 89.9) |
| By age strata§ (years) | |||||
| <18 | 55 | 47 | 8 | 0 | 85.5 (73.8 to 92.4) |
| 18–64 | 93 | 76 | 17 | 0 | 81.7 (72.7 to 88.3) |
| 65+ | 50 | 38 | 11 | 1 | 76.0 (62.6 to 85.7) |
*Time periods (1, 1.5, or 2 years) refer to the period of days immediately preceding the index date for which there was no evidence of antidepressant exposure. Further restriction to participants with standardized antidepressant dose ratio ≤1.0 improved PPV estimates to 90.8% (95% CI 85.1% to 94.4%) for the 1-year window, to 90.8% (95% CI 85.0% to 94.6%) for the 1.5-year window, and to 90.8% (95% CI 85.0% to 94.6%) for the 2-year window.
†Requiring a minimum of 1 year of Olmsted County residence prior to the index date and further restriction to participants with standardized antidepressant dose ratio ≤1.0 improved the PPV estimate to 90.6% (95% CI 85.1% to 94.2%).
‡Restriction to participants with standardized antidepressant dose ratio ≤1.0 improved the PPV estimate to 89.5% (95% CI 80.6% to 94.6%) for males and to 93.2% (95% CI 85.9% to 96.8%) for females.
§Restriction to participants with standardized antidepressant dose ratio ≤1.0 improved the PPV estimate to 93.9% (95% CI 83.5% to 97.9%) for subjects aged <18 years, to 92.0% (95% CI 83.6% to 96.3%) for subjects aged 18–64 years, and to 85.4% (95% CI 71.6% to 93.1%) for subjects aged 65+ years.
AD, antidepressant; PPV, positive predictive value.