Completion and return of fall diaries varies with participants' level of education, first language, and baseline fall risk.

BACKGROUND Consensus guidelines recommend the use of prospective fall diaries in studies of fall rates. We sought to determine the characteristics associated with return and successful completion of a falls diary and whether characteristics such as gender, education level, native language, income, and falls risk influenced self-reported fall rates. METHODS Two hundred and seventy people aged 65 years and older participating in a randomized controlled trial evaluating two exercise programmes. Fall diaries were collected for 6 months, then evaluated for correct completion and falls reported. RESULTS An increasing risk of falls was associated with a reducing odds of returning diaries (odds ratio for a one unit increase in Falls Risk Assessment Tool score 0.71, 95% confidence interval 0.53-0.96). Native English speakers were more likely to complete more than half the diaries correctly (odds ratio 2.63, 95% confidence interval 1.20-5.75). CONCLUSIONS Problems arise in the correct completion of falls diaries among those for whom English is not their first language. Diaries may underreport the rate of falls as those at higher risk were less likely to return diaries but more likely to report falls. Careful consideration should be given to the analysis of falls diaries as missing data are unlikely to be missing completely at random. We recommend additional training in the use of falls diaries for these groups or the utilization of simpler instruments.