The results of this retrospective cohort study revealed two aspects concerning nutritional status in patients with OVCF. First, this study suggested that malnutrition was a risk factor for reduced ADL in OVCF. Second, malnutrition may increase the risk of falling after OVCF. This study supports the hypothesis that better nutritional status is associated with improved ADL and functional status after OVCF. There are no reports describing the relationship between nutritional assessment using GNRI and functional prognosis of OVCF, to our knowledge, this is the first study to show the impact of nutritional status on ADL in patients with OVCF.
First, we found that malnutrition may lower ADL after OVCF. Some reports have described the relationship between nutritional status and ADL, and suggested that ADL is lower in cases of malnutrition. Bakker et al.  reported that malnutrition is associated with lower ADL, QoL, and longer hospital stay and rehabilitation. Moreover, Bakker et al.  and Osta et al.  reported malnutrition in 4.8% and 13.5% of elderly patients, respectively. In our study, the prevalence of malnutrition was higher than in other studies. For this reason, Bakker et al.  and Osta et al.  reported that weight loss was included in nutritional assessment. Since the item of weight loss was not included in GNRI which we used as an index for nutritional status, it was considered that there was a case in which nutrition disorder was considered even in the absence of weight loss. In addition, since the subjects were patients with OVCF, undernutrition itself was considered to be a risk for fracture, which may have resulted in a high proportion of malnutrition. Nutritional assessment using GNRI and appropriate nutritional assessment may improve ADL.
Second, low GNRI was associated with a higher risk of falls after OVCF. In a previous study on fall risk, Hong et al.  noted age, gender, marital status, self-rated health, number of chronic diseases, number of disability items, ADL, and physical functioning as risk factors for falls in the elderly. Galet et al.  reported that the rate of readmission due to falls increased from 15.6% in 2010 to 17.4% in 2014, necessitating a fall prevention program. In this current study, falls after OVCF were negatively correlated with GNRI, serum albumin, and JOA scores, and the total number of drugs on admission was positively correlated. These results suggest that malnutrition, functional decline, and polypharmacy are associated with falls after OVCF. Furthermore, a logistic regression analysis using propensity score matching for the probability of falls after OVCF showed that GNRI had an influence on the probability of falls after OVCF. Malnutrition reduces body weight and skeletal muscle mass by breaking down muscle and fat for energy; as a result, it was considered that balance ability and walking ability decreased, and fall risk increased.
Bonafede et al.  described the risk factors for falls in OVCF as osteoporosis and no recent fracture, falls, older age, poor health status, and comorbidities, but did not mention motor function or nutritional assessment. However, in our study, age, comorbidities were not correlated with BI gain and falls after OVCF, and JOA scores for motor function assessment and nutritional assessment influenced falls and ADL acquisition after OVCF. These results suggest that better motor function and nutritional status may reduce falls after OVCF. From these results, it was considered that nutrition assessment and preparation of fall prevention programs were necessary in order to prevent falls after OVCF. In addition, GNRI is a simple and accurate tool for predicting the risk of mortality in hospitalized elderly patients. In this study, low GNRI on admission in OVCF patients may increase the risk of falls.
Regarding the relationship between GNRI and BMD, this study showed a positive correlation between GNRI and BMD. There are several reports on the relationship between osteoporosis and nutrition [30, 31]. As for the relationship between nutritional status and bone density, Chen et al.  found that when GNRI was high, bone density and grip strength were high. The nutritional evaluation using GNRI is important for the motor function improvement.
This study had a few limitations. First, detailed assessment of sarcopenia and muscle strength, balance assessment, and pain assessment were insufficient for the retrospective study. Second, the assessment of living conditions, such as family members living together, employment, and the presence or absence of stairs in the house, was insufficient. It is necessary to carry out the evaluation of such life situation in future.