Balance dysfunction the most significant cause of in-hospital falls in patients taking hypnotic drugs: A retrospective study

Abstract

Purpose: Preventing falls in patients is one of the most important concerns in acute hospitals. Balance disorder and hypnotic drugs lead to falls. The Standing Test for Imbalance and Disequilibrium (SIDE) is developed for the evaluation of static standing balance ability. There have been no reports of a comprehensive assessment of falls risk including hypnotic drugs and SIDE. The purpose of this study was to investigate the fall rate of each patient who took the hypnotic drug and the factor associated with falls.

Methods: Fall rates for each hypnotic drug were calculated as follows (number of patients who fell/number of patients prescribed hypnotic drug x 100). We investigated the hypnotic drugs as follows; benzodiazepine drugs, Z-drugs, melatonin receptor agonists, and orexin receptor antagonists. Hypnotic drug fall rate was analyzed using Pearson's chi-square test. Decision tree analysis is the method we used to discover the most influential factors associated with falls.

Results: This study included 2840 patients taking hypnotic drugs. Accidents involving falls were reported for 211 of inpatients taking hypnotic drugs. Z-drug recipients had the lowest fall rate among the hypnotic drugs. We analyzed to identify independent factors for falls, a decision tree algorithm was created using two divergence variables. The SIDE levels indicating balance disorder were the initial divergence variable. The rate of falls in patients at SIDE level ≦ 2a was 14.7%. On the other hand, the rate of falls in patients at SIDE level ≧ 2b was 2.9%. Gender was the variable for the second classification. In this analysis, drugs weren't identified as divergence variables for falls.

Conclusion: The SIDE balance assessment was the initial divergence variable by decision tree analysis. In order to prevent falls, it seems important not only to select appropriate hypnotic drugs but also to assess patients for balance and implement preventive measures.

Fig 1. Diagram of patient’s inclusion and exclusion criteria in this study.

All patients admitted to our hospital from July to December 2020 who were prescribed hypnotic drugs were included in the study. Finally, 2840 patients were included in the analysis.

Fig 2. Standing Test for Imbalance and Disequilibrium (SIDE).

The patients perform the static balance test in the following order, standing with feet apart, standing with feet together, tandem standing, and standing on one foot. After checking which movements are possible or impossible for the patient, the medical staff assesses the patients into six levels: Level 0, 1, 2a, 2b, 3, and 4. Level 0: The patient can’t stand with feet apart without assistance. Level 1: The patient can stand with feet apart without assistance. However, the patients can’t stand with feet together for more than 5 s. Level 2a: The patient can stand with feet together for more than 5 s. However, the patients can’t stand in a tandem position with either foot forward. Level 2b: The patient can stand tandem with one but not the other foot in the leading position for more than 5 s. Level 3: The patient can stand tandem standing with each foot forward for more than 5 s. However, the patient can’t stand on one foot more than 30 s. Level 4: The patient can stand on one foot more than 30 s with either foot.

Fig 3. Fall rate for each hypnotic drug.

Fall rate for z-drugs was significantly lower than those for benzodiazepine drugs and orexin receptor antagonists. *: means statistically significant.

Fig 4. Age and ratio of balance disorder and each patient who was prescribed hypnotic drugs.

The patients taking z-drugs were significantly younger than those taking melatonin receptor agonists and orexin receptor antagonists. The ratio balance disorder in the patients taking z-drugs was significantly smaller than that of melatonin receptor agonists and orexin receptor antagonists. *: means statistically significant.

Fig 5. Decision-tree algorithm for falls in hospitalized patients taking hypnotic drugs.

The pie indicates the proportion of patients with falls (black) and without falls (white). The falls rate in patients at SIDE level 2a or lower was five times the falls rate in patients at SIDE level 2b or higher. In addition, the falls rate in males was higher than in females for SIDE level 2a or lower.