Table 1.
Baseline Demographic and Clinical Characteristics According to Study Group.*
| Characteristic | Trimethoprim–Sulfamethoxazole (N = 302) | Placebo (N = 305) | Overall (N = 607) |
|---|---|---|---|
| Age | |||
| Median — mo | 12 | 12 | 12 |
| Interquartile range — mo | 5–31 | 6–30 | 6–31 |
| Group — no. (%) | |||
| 2–11 mo | 151 (50.0) | 147 (48.2) | 298 (49.1) |
| 12–23 mo | 48 (15.9) | 59 (19.3) | 107 (17.6) |
| 24–35 mo | 43 (14.2) | 36 (11.8) | 79 (13.0) |
| 36–72 mo | 60 (19.9) | 63 (20.7) | 123 (20.3) |
| Sex — no. (%) | |||
| Male | |||
| Circumcised | 11 (3.6) | 7 (2.3) | 18 (3.0) |
| Uncircumcised | 14 (4.6) | 17 (5.6) | 31 (5.1) |
| Female | 277 (91.7) | 281 (92.1) | 558 (91.9) |
| Race — no./total no. (%)† | |||
| White | 245/298 (82.2) | 237/299 (79.3) | 482/597 (80.7) |
| Black | 10/298 (3.4) | 17/299 (5.7) | 27/597 (4.5) |
| Multiracial | 20/298 (6.7) | 20/299 (6.7) | 40/597 (6.7) |
| Other | 23/298 (7.7) | 25/299 (8.4) | 48/597 (8.0) |
| Hispanic ethnic group — no./total no. (%)† | 31/300 (10.3) | 46/304 (15.1) | 77/604 (12.7) |
| Educational level of primary caregiver — no./total no. (%) | |||
| High-school graduate or lower | 78/299 (26.1) | 80/303 (26.4) | 158/602 (26.2) |
| Some college or 2-yr degree | 78/299 (26.1) | 78/303 (25.7) | 156/602 (25.9) |
| College graduate or higher | 143/299 (47.8) | 145/303 (47.9) | 288/602 (47.8) |
| Health insurance — no./total no. (%) | |||
| Commercial | 228/299 (76.3) | 211/302 (69.9) | 439/601 (73.0) |
| Public‡ | 71/299 (23.7) | 91/302 (30.1) | 162/601 (27.0) |
| Index UTI — no. (%) | |||
| First episode | 275 (91.1) | 279 (91.5) | 554 (91.3) |
| Second episode | 27 (8.9) | 26 (8.5) | 53 (8.7) |
| Febrile only | 96 (31.8) | 100 (32.8) | 196 (32.3) |
| Symptomatic only | 49 (16.2) | 37 (12.1) | 86 (14.2) |
| Febrile and symptomatic | 157 (52.0) | 168 (55.1) | 325 (53.5) |
| Susceptibility of index UTI to trimethoprim–sulfamethoxazole— no./total no. (%) | |||
| Resistant§ | 55/278 (19.8) | 65/293 (22.2) | 120/571 (21.0) |
| Sensitive | 223/278 (80.2) | 228/293 (77.8) | 451/571 (79.0) |
| Bladder and bowel dysfunction — no./total no. (%)¶ | 34/63 (54.0) | 37/63 (58.7) | 71/126 (56.3) |
| Constipation — no./total no. (%)|| | 8/65 (12.3) | 8/64 (12.5) | 16/129 (12.4) |
| Ultrasound abnormalities — no./total no. (%) | |||
| Hydronephrosis** | 19/300 (6.3) | 13/302 (4.3) | 32/602 (5.3) |
| Ureter duplication | 18/300 (6.0) | 15/302 (5.0) | 33/602 (5.5) |
| Highest degree of vesicoureteral reflux — no./total no. (%)†† | |||
| Grade I | 35/301 (11.6) | 33/301 (11.0) | 68/602 (11.3) |
| Grade II | 123/301 (40.9) | 131/301 (43.5) | 254/602 (42.2) |
| Grade III | 118/301 (39.2) | 112/301 (37.2) | 230/602 (38.2) |
| Grade IV | 25/301 (8.3) | 25/301 (8.3) | 50/602 (8.3) |
| Bilateral vesicoureteral reflux — no./total no. (%) | 146/300 (48.7) | 141/300 (47.0) | 287/600 (47.8) |
| Renal scarring — no./total no. (%)‡‡ | |||
| None | 280/292 (95.9) | 281/290 (96.9) | 561/582 (96.4) |
| Mild | 1/292 (0.3) | 0/290 | 1/582 (0.2) |
| Moderate | 3/292 (1.0) | 2/290 (0.7) | 5/582 (0.9) |
| Severe | 4/292 (1.4) | 2/290 (0.7) | 6/582 (1.0) |
| Global atrophy | 4/292 (1.4) | 5/290 (1.7) | 9/582 (1.5) |
There were no significant differences between the study groups in any of the baseline characteristics (P>0.05). UTI denotes urinary tract infection.
Race and ethnic group were reported by the parent or guardian.
Four children with no insurance were classified as having public insurance.
Included in this category are children whose index infection was caused by enterococcus or pseudomonas, was not tested for susceptibility to trimethoprim–sulfamethoxazole, and was assumed to be resistant and children whose index infection was caused by bacteria that were resistant to trimethoprim but were not tested for susceptibility to sulfamethoxazole.
Bladder and bowel dysfunction was defined as a score of more than 6 for toilet-trained girls and more than 9 for toilet-trained boys on a modified Dysfunctional Voiding Scoring System.17 Scores range from 0 to 30, with higher scores indicating greater bladder and bowel dysfunction.
Constipation was defined as two or more conditions according to modified criteria of the Paris Consensus on Childhood Constipation Terminology Group18 (<3 bowel movements per week, >1 episode of fecal incontinence per week, passage of a large stool that obstructed the toilet, retentive posture and behavior, and pain during defecation).
All 32 children had hydronephrosis of less than grade 4 on the Society for Fetal Urology scale.
Seven children with central assessment of no vesicoureteral reflux were included in grade I, and one child with central assessment of grade V was included in grade IV (with enrollment based on local readings). Data on voiding cystourethrography for five children were missing because images were not available for central evaluation.
A total of 25 children did not undergo renal scanning with technetium-99m–labeled dimercaptosuccinic acid at baseline. Among 98 children (40 in the trimethoprim–sulfamethoxazole group and 58 in the placebo group) in whom scanning was performed less than 31 days after the index UTI, scarring was identified in 1 child in the trimethoprim–sulfamethoxazole group. All other instances of scarring were identified in the 484 children (252 in the trimethoprim–sulfamethoxazole group and 232 in the placebo group) in whom scanning was performed between 31 and 112 days after the index UTI.