Table 2.
The follow-up rate at each annual interval after subjects (N = 610) in a retrospective cohort study of 3-year and 5-year prostate cancer (PrCa) recurrence risk based on electronic medical record (EMR) data
| Follow-upb | Nc | Percentage Method η percentage |
Estimated follow-up using the formal method η FPT | Clark’s completeness index η CCI |
Simplified Person-time Method η SPT |
|---|---|---|---|---|---|
| 1 Year | 558 | 91.4% | 95.7% | 95.5% | 95.7% |
| 2 Year | 472 | 86.2% | 95.0% | 94.5% | 95.0% |
| 3 Year | 383 | 80.9% | 93.6% | 92.9% | 93.8% |
| 4 Year | 295 | 75.6% | 92.5% | 92.3% | 93.3% |
| 5 Year | 197 | 67.5% | 91.8% | 91.8% | 93.0% |
Follow-up rates were estimated using four methods, namely, (i) the standard Percentage Method (Eq. 1 a), (ii) the formal Method (FPT, Eq. 4), (iii) the Clark’s completeness index (CCI, Eq. 2), and (iv) the Simplified Person-Time Method (SPT, Eq. 5)
aEquations are shown in the next
bA retrospective cohort study was conducted among incident PrCa patients who underwent robotic assisted laparoscopic prostatectomy (RALP) by a single surgeon at Montefiore Medical Center (MMC) in the Bronx from 10/2005 through 12/2012. These subjects were followed for disease recurrence or progression through December 2012. A total of N = 610 PrCa patients who underwent RALP and had their follow-up at MMC were included in this analysis
cWe calculated the follow-up rate at each year among the subset of the patients who had RALP early enough to be eligible for such length of follow-up. For example, to estimate the three year follow-up rate, we calculated this rate among the subjects who had RALP at least before 12/31/2009