Table 1.
Baseline characteristics. Data are number (%) of participants unless stated otherwise
| Intention-to-treat population | Modified intention-to-treat population | ||||
|---|---|---|---|---|---|
| Antibiotic prophylaxis (n=120) | Methenamine hippurate (n=120) | Antibiotic prophylaxis (n=102) | Methenamine hippurate (n=103) | ||
| Mean (standard deviation) age (years) | 50.3 (18.1) | 49.9 (19.1) | 51.1 (17.7) | 51.1 (18.9) | |
| Mean (standard deviation) weight (kg) | 70.1 (15.3) | 75.1 (18.5) | 69.4 (14.6) | 75.5 (18.5) | |
| Menopausal status | |||||
| Pre-menopausal | 49 (41) | 50 (42) | 40 (39) | 41 (40) | |
| Peri-menopausal/post-menopausal | 71 (59) | 70 (58) | 62 (61) | 62 (60) | |
| No (%) of self-reported urinary tract infections in previous 12 months before trial entry | |||||
| <4 | 14 (12) | 16 (13) | 12 (12) | 16 (16) | |
| ≥4 | 106 (88) | 104 (87) | 90 (88) | 87 (84) | |
| Median (interquartile range) | 6 (4-8) | 6 (4-8) | 6 (4-8) | 6 (4-8) | |
| Mean (standard deviation) | 6.8 (3.8) | 7.0 (3.4) | 6.6 (3.8) | 6.7 (3.3) | |
| No of positive urine culture reports in previous 12 months before trial entry* | |||||
| Median (interquartile range) | 2 (1-4) | 3 (1-5) | 2 (1-4) | 3 (1-5) | |
| Previous use of antibiotic prophylaxis | 28 (23) | 27 (23) | 23 (23) | 22 (21) | |
| Nitrofurantoin | 20 (17) | 20 (17) | 17 (17) | 17 (17) | |
| Trimethoprim | 16 (13) | 11 (9) | 13 (13) | 9 (9) | |
| Cefalexin | 6 (5) | 13 (11) | 2 (2) | 9 (9) | |
| Co-amoxyclav | 2 (2) | 5 (4) | 0 (0) | 4 (4) | |
| Amoxycillin | 3 (3) | 3 (3) | 0 (0) | 2 (2) | |
| Ciprofloxacin | 1 (1) | 4 (3) | 0 (0) | 3 (3) | |
| Pivmecillinam | 1 (1) | 3 (3) | 1 (1) | 3 (3) | |
| Three month washout period required before randomisation | 16 (13) | 16 (13) | 15 (15) | 14 (14) | |
| Previously taken methenamine hippurate | 2 (2) | 4 (3) | 2 (2) | 3 (3) | |
| Results of central laboratory urine culture at baseline | |||||
| No growth | 93 (78) | 98 (82) | 82 (80) | 84 (82) | |
| Growth of one or two isolates | 18 (15) | 13 (11) | 16 (16) | 13 (13) | |
| No sample | 9 (8) | 9 (8) | 4 (4) | 6 (6) | |
| Isolates identified from central laboratory urine culture at baseline | |||||
| Escherichia coli | 15 (13) | 7 (6) | 14 (14) | 7 (7) | |
| Coliform—other | 1 (1) | 2 (2) | 1 (1) | 2 (2) | |
| Enterobacter cloacae group | 1 (1) | 0 | 0 | 0 | |
| Pseudomonas aeruginosa | 0 | 1 (1) | 0 | 1 (1) | |
| Enterococcus faecalis | 1 (1) | 0 | 1 (1) | 0 | |
| Staphylococcus aureus | 0 | 1 (1) | 0 | 1 (1) | |
| Streptococcus agalactiae | 1 (1) | 2 (2) | 1 (1) | 2 (2) | |
| Resistance in any isolate identified from central laboratory urine culture at baseline | |||||
| Amoxicillin | 9 (8) | 6 (5) | 8 (8) | 6 (6) | |
| Co-amoxiclav | 3 (3) | 1 (1) | 2 (2) | 1 (1) | |
| Trimethoprim | 9 (8) | 3 (3) | 8 (8) | 3 (3) | |
| Co-trimoxazole | 3 (3) | 1 (1) | 2 (2) | 1 (1) | |
| Cefalexin | 4 (3) | 3 (3) | 3 (3) | 3 (3) | |
| Cefuroxime | 2 (2) | 2 (2) | 1 (1) | 2 (2) | |
| Cephalosporins—other | 1 (1) | 1 (1) | 1 (1) | 1 (1) | |
| Ciprofloxacin | 0 | 3 (3) | 0 | 3 (3) | |
| Gentamicin | 1 (1) | 1 (1) | 1 (1) | 1 (1) | |
| Nitrofurantoin | 1 (1) | 1 (1) | 0 | 1 (1) | |
*
Data missing for three participants allocated to receive antibiotic prophylaxis and for three participants allocated to receive methenamine hippurate.