Table 2.
Enrollment and endpoint classification
| Subset Comparison | ||||
|---|---|---|---|---|
| Trial Attribute | Nephrology (n=1054) | Cardiologya (n=2264) | P-value | Otherb (n=37,652) |
| Enrollment | n=1041 | n=2240 | <0.001 | n=37,085 |
| Mean | 178 ±621 | 557±2143 | 451 ± 14,582 | |
| Median | 68 [30–156] | 112 [50–300] | 61 [30–172] | |
| Patient enrollment | n=1041 | n=2240 | <0.001 | n=37,085 |
| 0 | 4 (0.4) | 0 (0.0) | 82 (0.2) | |
| 1–10 | 58 (5.6) | 62 (2.8) | 1555 (4.2) | |
| 11–50 | 376 (36.1) | 564 (25.2) | 14,329 (38.6) | |
| 51–100 | 233 (22.4) | 449 (20.0) | 7760 (20.9) | |
| 101–500 | 310 (29.8) | 818 (36.5) | 10,310 (27.8) | |
| 501–1000 | 42 (4.0) | 150 (6.7) | 1796 (4.8) | |
| >1000 | 18 (1.7) | 197 (8.8) | 1253 (3.4) | |
| Study duration | n=970 | n=2129 | 0.002 | n=34,803 |
| Mean (mo) | 26 ± 20 | 28 ± 23 | 25 ± 24 | |
| Median (mo) | 21 [12–34] | 24 [13–36] | 20 [11–34] | |
| Endpoint classification | n=906 | n=1869 | <0.001 | n=30,060 |
| Safety | 54 (6.0) | 139 (7.4) | 2721 (9.1) | |
| Efficacy | 302 (33.3) | 747 (40.0) | 10,164 (33.8) | |
| Safety/efficacy | 450 (49.7) | 918 (49.1) | 13,871 (46.1) | |
| Bio-equivalence | 9 (1.0) | 3 (0.2) | 935 (3.1) | |
| Bio-availability | 3 (0.3) | 0 (0.0) | 242 (0.8) | |
| Pharmacokinetics | 58 (6.4) | 15 (0.8) | 1112 (3.7) | |
| Pharmacodynamics | 12 (1.3) | 28 (1.5) | 425 (1.4) | |
| Pharmacokinetics/dynamics | 18 (2.0) | 19 (1.0) | 590 (2.0) | |
| Missing | 148 (14.0) | 395 (17.4) | 0.01 | 7592 (20.2) |
| No. of primary outcomes measured | n=1039 | n=2230 | 0.3 | n=36,982 |
| Mean | 1.2 ± 0.75 | 1.2 ± 0.87 | 1.3 ± 1.06 | |
| Median | 1 [1.0–1.0] | 1 [1.0–1.0] | 1 [1.0–1.0] | |
| A primary outcome measures safety | 338/996 (33.9) | 785/2153 (36.5) | 0.2 | 10,106/35,421 (28.5) |
| No. of secondary outcomes measured | n=1040 | n=2232 | <0.001 | n=36989 |
| Mean | 2.2 ± 2.88 | 2.9 ± 5.33 | 2.4 ± 3.29 | |
| Median | 1 [1.0–3.0] | 1 [1.0–4.0] | 1 [1.0–3.0] | |
| A secondary outcome measures safety | 363/815 (44.5) | 836/1765 (47.4) | 0.2 | 113,07/35,646 (31.7) |
Note: Values for categorical variables are given as number (percentage) or n/N (percentage); values for continuous variables are given as mean ± standard deviation or median [interquartile range]. Differences in missing data between trials were not significant unless specified in the table. Chi-squared test used for class variables, Wilcoxon rank sum test used for continuous variables.
Abbreviations: IQR, interquartile range; SD, standard deviation.
a
Excludes studies classified as both nephrology and cardiology.
b
Excludes studies classified as nephrology or cardiology.