Construction and verification of a model for predicting fall risk in patients with maintenance hemodialysis†

Comprehensively using literature research method, expert discussion method, etc., patients with self-compiled MHD fall questionnaire included the following 4 parts. (1) General information of patients: age and gender; (2) health status investigation: dialysis period (months), whether it is complicated with cardiovascular disease, whether hearing or vision is reduced, whether assistive devices are used, whether there is a fall in the past 1 year, whether it is weak (using the⁹ Fatigue, Resistance, Ambulation, Illness, Loss of Weight (FRAIL) weakness scale), and whether there is dialysis-related hypotension; (3) laboratory indicators (before the latest dialysis at enrollment): hemoglobin, serum albumin, serum phosphorus, serum calcium, and fasting blood glucose; and (4) physical function assessment: grip strength test¹⁰ and time up and go (TUG) test.

Systolic blood pressure decreased by ≥20 mmHg (or mean arterial pressure decreased by ≥10 mmHg) during dialysis, symptoms of hypotension were existed, or intervention was needed.¹¹ It was defined as IDH of the patient whose blood pressure was collected after each hemodialysis if the incidence of IDH was ≥1/10 during this study.

The subject’s legs should be naturally separated into an upright posture, and the arms are naturally drooping. It is necessary to take the maximum value from 2 times holding the grip dynamometer with full force. The grip dynamometer adopted Xiangshan EH101 grip dynamometer.

The criteria were as follows: sudden involuntary changes in position, causing any part of the body other than the feet to touch the ground accidentally, and excluding falls caused by disability, onset of disease, external violence, or environmental factors.

Frailty referred to a syndrome with increased vulnerability caused mainly by physical weakness, body degeneration, and a variety of chronic diseases.¹² FRAIL scale was adopted in this study to evaluate the frailty of the patients. Mcadams-Demarco et al.¹³ found that weakness combined with patients with MHD s is an independent risk factor for falls. It was the same as this study that showed that weakness combined with patients with MHD is positively correlated with falls in patients with MHD whose OR value (OR = 7.770) was higher than other influencing factors, indicating that weakness was the most important influencing factor for falls in patients with MHD. The main reason may be that FRAIL indicators in the FRAIL scale, such as fatigue, sense of resistance¹⁴, and low activity, could reflect patients’ impaired energy and physical strength, which could directly increase patients’ risk of falling.¹⁵ Liang¹⁵ found that frailty of patients with MHD was associated with no exercise and low pre-protein, which suggested that when formulating fall prevention measures for patients with MHD, nurses could arrange patients with MHD to enhance moderate impedance exercise and aerobic endurance exercise, routinely screen patients with MHD for frailty, and conduct health education on the prevention as well as treatment of frailty.

Gait instability had been recognized as a relatively stable risk factor for falls.¹⁰ The decline of the body’s function from patients with MHD due to the combined effects of their own diseases, drugs, and dialysis treatment led to the decline of gait stability and balance ability. St. Thomas Risk Assessment Tool in Falling Elderly Inpatients (Stratify), TUG, Berg Balance Scale (BBS), Short Physical Performance Battery (SPPB), etc. were commonly used for clinical gait and balance screening methods. Considering risk prediction tools requiring to be as simple and efficient as possible, this study chose the simplest and the most efficient TUG test among them. This study showed that the TUG test was associated with falls in patients with MHD, namely, the incidence of falls in patients with MHD was higher when the TUG test was ≥13.5 s than when the TUG test was <13.5 s,¹⁶ which were consistent with previous systematic reviews. The TUG test had good clinical efficacy in distinguishing between low- and high-fall risks, which was an ideal tool for evaluating gait and balance.

The results of this study showed that the risk of falling in patients with MHD who had fallen in the past year was 3.951 times than who had not fallen in the past year,⁶ which was basically consistent with previous studies. Fall history could be regarded as one of the high-risk factors for falling. However,² some experts believed that fall history was retrospective information, which may cause bias. Therefore, when collecting the fall history, nurses could conduct real-time inquiry weekly to record whether patients with MHD have fallen or not. On the one hand, the accuracy of information collection could be ensured; on the other hand, early detection and intervention could be realized to avoid patients with MHD from falling again and improve the life quality of the patients.

This study found that the serum albumin level was one of the independent factors affecting patients’ falls,¹⁷ which was basically consistent with Liu Anping’s study because serum albumin was an endogenous nutrient synthesized by the liver, whose level could reflect the nutritional status of the patient. When the serum albumin level was low, it meant that the patient’s nutritional intake is insufficient. Reservoir muscles would accelerate their own breakdown and consumption, leading to a decrease in muscle mass and limb function of patients, which would increase the risk of falls. Therefore, for patients with MHD with low serum albumin levels, nursing staff could pay attention to daily diet guidance for patients and suggest them to take more high-protein foods, such as beef, fish, eggs, milk, soybean, etc. Protein powder could be supplemented appropriately. For some patients who cannot eat, enteral and parenteral nutrition could also be implemented to improve the serum albumin level of patients.

This study showed that patients with MHD with higher fasting blood glucose concentrations had a higher risk of falls. Blood glucose concentration was an important indicator for judging whether patients had diabetes mellitus.^2,18 Previous studies believed that diabetes mellitus was a risk factor for falls in patients with MHD, which were similar as the results of this study. Diabetic patients often have microvascular and macrovascular complications, such as cardiovascular and cerebrovascular diseases, autonomic neuropathy, peripheral neuropathy, retinopathy, and vision loss. Besides, the persistent high blood sugar toxicity could cause arterial occlusion of the lower extremities, which reduced the motor function of the legs, leading to increase the risk of falls. Therefore, nurses needed to strengthen health education for patients with hyperglycemic MHD, guide them to avoid eating too much high-sugar and high-carbohydrate diet, and at the same time, conduct moderate aerobic exercises, such as Tai Chi, brisk walking, etc., so as to actively control blood sugar and delay diabetes progression of retinal and neuropathy to avoid the falls.

Roberts et al.¹⁹ found that orthostatic hypotension is a predictor of falls in patients with MHD, which is consistent with the results of this study. Orthostatic hypotension is one of the acute complications of patients with MHD, mainly due to the fact that the intravascular blood volume of patients with hemodialysis needed to be transferred to the outside of the body through ultrafiltration, and then, the fluid in the interstitial space was likely to be insufficiently compensated, resulting in insufficient effective circulating blood volume of the body and ischemia of important organs, such as insufficient blood supply to the brain. The attack was often accompanied with sweating, dizziness, vertigo, yawning, and desire to defecate or incontinence, and those with a significant drop in blood pressure might also have symptoms, such as angina, arrhythmia, vomiting, and lethargy, which often led to falls. Therefore, on the one hand,²⁰ medical staff could choose the appropriate hemodialysis method to avoid excessive dialysis; on the other hand, body position management and safety guidance should be conducted for patients with MHD with orthostatic hypotension, such as informing patients of the correct way to get up, avoiding standing up suddenly and standing for a long time, defecating hard, avoiding high temperature environment, etc.