Objectives: To assess the reliability of symptom reports in 3-day vs 7-day bladder diaries used in clinical trials of patients with overactive bladder (OAB) and to compare those results and related issues with previous reports.
Materials and methods: We analysed two large-scale, randomized, phase 3 clinical trials of the use of transdermal oxybutynin for treating patients with OAB. The first trial (Trial A, 520 patients) compared three doses of transdermal oxybutynin (1.3, 2.6 and 3.9 mg/day) with placebo. Patients documented their OAB symptoms in a 7-day diary. The second clinical study (Trial B, 361 patients) compared the efficacy of 3.9 mg/day transdermal oxybutynin with 4 mg/day extended-release tolterodine and with placebo; this trial required symptom recording for only 3 days. The internal consistency of the data from the 7-day trial was determined and then compared with the 3-day trial results.
Results: Patients on transdermal oxybutynin or long-acting tolterodine for their OAB symptoms showed a clinically and statistically significant improvement, results that were documented in both 3-day and 7-day bladder diaries. However, compared with 7-day symptom records, 3-day diaries were associated with significantly better compliance with record-keeping (P < 0.001).
Conclusions: Seven-day diaries used in clinical trials supply accurate and reproducible data on clinical manifestations of OAB, but 3-day diaries are equally effective and have the potential for better accuracy through increased patient convenience. Three-day diaries may also reduce the tendency for patients to complete gaps in record-keeping from memory.