All four systematic reviews determined that impaired mental status and a history of falls are common factors associated with accidental falls in acute settings. See below for other risk factors.

Summary:

Arch Phys Med Rehabil. 2014 Jan;95(1):50-57.
After conducting a systematic review of the literature to identify risk factors, researchers linked the 88 factors to 66 International Classification of Functioning, Disability, and Health (ICF) categories and 5 personal factors (see Appendix 1). Twenty multidisciplinary participants from different institutions completed three rounds of rating the importance of each category and factor regarding falls in acute rehabilitation settings using a 5-point Likert scale.
RESULTS: Thirty-four ICF categories and two personal factors achived threshold values of importance, and their scores are listed in Table 1. Of these, items scored 4.9 or 5.0 include four body functions (consciousness fuctions (i.e. confusion/disorientation), sensations association with hearing and vestibular function (i.e. dizziness/vertigo), muscle power functions (i.e. motor status related to stroke), and gait pattern functions (i.e. gait stability)), one activity (walking), and one personal factor (previous falls).

Arch Gerontol Geriatr. 2013 May-Jun;56(3):407-415.
Systematic review with ten studies that met the inclusion criteria for studies on older hospital patients. When there were at least 3 studies investigating a factor in a comparable way in a specific setting, researchers computed the pooled odds ratio (OR) using random effect models.
RESULTS: Six risk factors for older hospital inpatients (HI) were considered, and the strongest association was a history of falls (OR=2.85). Other risk factors that were significantly associated with falls were cognitive impairment (OR = 1.52 overall, OR = 1.65 multivariate), use of sedatives (OR = 1.89 overall and multivariate), and use of antidepressants (OR = 1.98 overall and multivariate).

Age Ageing. 2004 Mar;33(2):122-30.
This is a systematic review of thirteen studies that described risk factors in a variety of inpatient settings.
RESULTS: A small number of factors were repeatedly found to be significant: gait instability, lower limb weakness, previous fall history, medications, toileting factors (urinary incontinence/frequency or need for assistance), and agitation/confusion or impaired judgement. See Table 3 for odds ratios and confidence intervals for all risk factors.

Int J Nurs Pract. 2001 Feb;7(1):38-45
This is a systematic review of 13 case-control and 5 cohort studies of patient falls in hospitals.
RESULTS: Factors associated with increased risk of falling included special toileting needs (incontinence, needing assistance, having diarrhea), impaired mobility or use of mobility aid, impaired mental status, and history of falling. Doesn’t provide any numerical risk data.

Reviewed and updated 4/10/2014 ldt