Assessing the specific needs of the growing number of older ER users is a priority, if we wish to reduce the occurrence of the short-term age-related adverse ER outcomes. Screening individuals with a high risk for adverse outcomes is the first step of an effective care plan. ER² is a standardized and validated tool which screens inpatients at risk for age-related adverse events which may arise during their hospitalization. The item answers of ER² depend on objective information, except for factors which relate to any history of falls. Obtaining valid information for this item may be difficult due to the high prevalence of cognitive impairment in older inpatients. History of falls was chosen because it is a good marker of mobility impairment and dependence. The use of a walking aid is a similar marker, which is more objective and easier to collect. Thus, we theorized that the use of a walking aid instead of history of falls would not change the predictive value of the 6-item BGA for long length of hospital stay.

• To examine whether the modified ER² tool (i.e.; substituting the history of falls item for the use of walking aid item) successfully predicted the long length of hospital stay in geriatric patients admitted to the geriatric assessment unit

The modified 6-item BGA risk stratification predicted length of hospital stay at a better rate, when compared to a priori risk stratification using history of falls as an item. Recall bias relative to the history of falls may be considered a limitation when using the a priori BGA. Falls are usually underreported because of the cognitive decline of fallers, who forget to report them. This bias may underestimate their predictive value for length of hospital stay. The use of a walking aid, which has similar value in terms of gait and/or balance impairment marking, is more objective when compared to history of falls and, thus, may more efficiently detect the highest-risk inpatients, as suggested by our results.