Table 2. Secondary data and baseline covariates of patients included in DISCOVER CKD.
| Overall | TriNetX | Explorys (LCED) | DOPPS | CPRD | JMDV | |
|---|---|---|---|---|---|---|
| Secondary data | ||||||
| Database size,a GB | 76.8 | 53.1 | 16.9 | 7.1 | 15.4 | 8.1 |
| Total records, n | 1,042,035,868b | 417,339,825 | 181,577,200 | 3,852,045 | 250,747,268 | 46,344,726 |
| Procedure events | 22,756,095b | 10,962,854 | 5,129,753 | 16,626 | 3,512,078 | 4,143,808 |
| Coded outcomes, n | 21 | 20 | 19 | 1 | 18 | 14 |
| Diagnosis events | 168,815,184 | 84,116,926 | 73,572,637 | 108,890 | 7,865,001 | 3,151,730 |
| Coded outcomes, n | 63 | 57 | 57 | 18 | 60 | 56 |
| Drug prescription events | 364,318,203b | 46,335,922 | 25,870,962 | 452,163 | 124,011,918 | 23,449,842 |
| Medication classes, n | 57 | 42 | 46 | 20 | 46 | 38 |
| Laboratory/biochemistry measurements | 458,706,628 | 271,238,863 | 68,540,692 | 3,209,992 | 102,051,746 | 15,104,149 |
| Classes, n | 44 | 31 | 33 | 21 | 35 | 19 |
| Baseline covariatesc | ||||||
| Mean age at index, years (SD) | 68.5 (13.69) | 65.87 (13.41) | 69.93 (13.98) | - | 72.03 (12.76) | 75.99 (12.76) |
| Female, n (%) | 417,512 (55.7) | 264,633 (56.3) | 49,845 (54.7) | 8109 (42.7) | 104,650 (58.0) | 40,120 (50.0) |
| Mean BMI, kg/m2 (SD) | 28.89 (5.67) | 28.88 (5.37) | 30.19 (7.24) | - | 28.91 (6.26) | - |
| Mean baseline eGFR, mL/min/1.73 m2 (SD) | 49.45 (15.56) | 48.3 (16.48) | 52.07 (14.75) | - | 53.7 (11.08) | 49.16 (14.76) |
| CKD stage 2 or functional decline, n (%) | 139,973 (18.7) | 99,497 (21.2) | 31,458 (34.6) | - | 4683 (2.6) | 35,793 (44.6) |
| CKD stages 3–5, n (%) | 273,092 (36.4) | 13,4612 (28.6) | 49,579 (54.5) | 18,982 (100.0) | 80,650 (44.7) | 38,848 (48.4) |
| Diabetes mellitus, type 2, n (%) | 224,656 (30.0) | 162,293 (34.5) | 36,232 (39.8) | 18 (0.1) | 33,771 (18.7) | 28,574 (35.6) |
| Hypertension, n (%) | 483,061 (64.4) | 311,769 (66.3) | 76,185 (83.7) | 15,058 (79.3) | 98,554 (54.6) | 57,680 (71.9) |
| Heart failure, n (%) | 138,400 (18.5) | 71,987 (15.3) | 18,287 (20.1) | 4588 (24.2) | 12,528 (6.9) | 49,297 (61.5) |
aOverall database size is smaller than the sum of contributing sources due to data compression inside the Amazon Redshift cloud data warehouse.
bOverall events contain additional composite events generated following harmonization of data sources into the DISCOVER CKD retrospective cohort.
cOverall baseline covariates exclude LCED, which could not be pooled due to data privacy restrictions.
BMI, body mass index; CKD, chronic kidney disease; CPRD, Clinical Practice Research Datalink; DOPPS, Dialysis Outcomes and Practice Patterns Study; eGFR, estimated glomerular filtration rate; JMDV, Japan Medical Data Vision; LCED, Limited Claims and Electronic Health Record Dataset; SD, standard deviation.