Malnutrition is a common complication in acute care hospital patients and is related to poor outcomes. Therefore, the evaluation of nutritional status on admission to hospital is necessary to identify the patients at risk of malnutrition. A high prevalence of malnutrition in the hospital setting between 20% and 50% (
2,
14,
19), a range of 19% - 60% in inpatients (
20,
21), and 30% in outpatients has been documented in the literature (
20). These differences could be related to the definition and criteria used for malnutrition diagnosis (
14). Thus, the implementation of nutrition care programs in hospitals for identifying risk and diagnosis of malnutrition and its treatment has been recommended (
15). In Iran, nutrition screening upon admission in the hospital is recently compulsory. However, few reports have been published on the prevalence of malnutrition at admission to hospital (
6-
8). Some studies suggest a high prevalence of malnutrition with different tools (
4-
9). MUST, as a simple screening tool with good validity (sensitivity 80.6%, specificity 98.7%) and almost perfect agreement (k = 0.81) (
22) with a combined index (BMI and weight-loss), was considered in some studies (
2,
5,
16,
22).
In the present study, nutritional screening using MUST criteria showed that about two-fifths of patients had malnutrition, in which the majority of them were identified at high risk. This rate was greater than the rate reported in the Garcia et al. (
17) study, and other studies that had used a diverse tool for evaluation of malnutrition in hospitalized patients (
19). Stratton et al. (
16) also reported that according to the MUST criteria, more than half of the hospitalized patients were at risk of malnutrition.
The rate of malnutrition was markedly higher according to BMI and history of unintentional weight loss in the previous three to six months alone. This rate was similar to the results of Foadoddini et al. (
5), which was more than the rates reported by the study of Edington et al. (
23).
Physiologically, malnutrition leads to decreased whole body protein concentrations and muscle and fat mass (
24). Since, BMI alone is not a sensitive indicator to determine the fat and protein depletion, the measurement of mid-upper arm circumference “as a nutritional assessment tool to check for signs of muscle wasting” and serum albumin levels along with BMI accurately estimates body muscle mass and can increase the accuracy of malnutrition diagnosis (
4,
24).
Therefore, in this study, in addition to the evaluation of BMI and history of unintentional weight loss, to determine the malnutrition, mid-upper arm circumference (MUAC) and serum albumin levels were also assessed. The findings showed that half of the patients with MUAC < 5th and more than two thirds of those with serum levels of albumin < 3 g/dL were at a high risk of malnutrition. This represents an alarming situation, which malnutrition is common among hospitalized patients on admission, especially in the elderly, and in the absence of diagnosis, it can influence the treatment of patients, medical costs, the longer hospital stay, and mortality (
11). .
It was observed that between factors investigated, MUAC < 5th and hospitalized readmission ≥ 1, with a risk more than 2.5 fold, were more powerful predictors of malnutrition risk. In some studies, gender was a factor correlated to malnutrition, and the frequency observed in men was more than women (
4,
5,
11). The other studies revealed that weight loss during hospitalization was higher in women than in men (
6,
25). However, there was no significant gender difference in the risk of malnutrition in the present study. It was in agreement to the previous studies (
19,
26).
Some studies have shown that the prevalence of malnutrition increases with age (
5,
14,
27). In a study, the prevalence in age group < 30 years was more than other age groups, which might be related to the indicator of nutritional status in different studies (
4). Our findings showed that nearly half of the patients older than 50 years were at a high risk of malnutrition. The high prevalence of malnutrition in elderly patients can be related to an underlying disease, depression, inadequate nutrients intake, economic problems, and dental or chewing disorders (
28). It has been reported that gastrointestinal disorders may cause loss of appetite or impaired food intake, and increase the risk of malnutrition (
4,
11,
29). In addition, a significant relationship between malnutrition, with difficulty chewing and deglutition disorders, decreased appetite, nausea, and vomiting was shown in previous studies (
11,
29). In the present study, more than half of the patients had some gastrointestinal disorders. Among the disorders investigated (nausea and vomiting, diarrhea, constipation, difficulty chewing, and deglutition disorder), the most common ones were nausea, vomiting, and diarrhea. Of the total patients with gastrointestinal complaints, almost one third of them were at high risk of malnutrition, however, it was not statistically significant. The decreased appetite is also considered as an important variable associated with malnutrition (
11,
30), which may indirectly evaluate dietary intake (
11). The findings of our study showed that the patients with decreased appetite had nearly 1.2 fold higher risk of malnutrition. With regard to the findings, an adequate nutritional support in order to improve clinical outcome in these patients is recommended. Our findings demonstrated that the malnutrition risk was higher among patients admitted in the nephrology, surgery, and gastroenterology wards. In a study carried out by Foadoddini et al. (
5), high prevalence was shown in the surgery, infectious, and CCU wards. In another study, the highest prevalence of malnutrition was observed in geriatric, oncology, and gastroenterology departments (
14). The greater prevalence in surgery compared to oncology ward was reported in the study of Garcia et al. (
17). The prevalence of malnutrition in hospital admissions in different wards varies according to the criteria used, however, based on MUST, it is estimated that 20% - 60% of patients in the medical, surgical, geriatric, and orthopedic wards are to be affected (
5). The rates reported in our research and previous studies (
5,
14,
17) were in the same range. However, in the absence of appropriate screening procedures, the patients at risk of malnutrition in various wards of hospital do not seem to be recognized and/or are not referred for treatment (
5,
31).
In the present study, the chance of high risk of malnutrition in the patients with hospitalized readmission ≥ 1 was significantly higher than 2.5- fold compared to those not hospitalized. Similarly, a study conducted in Tehran showed that hospitalized readmission increased the malnutrition (
4), suggesting the hospitalized readmission could be considered as a main contributor to malnutrition.
In our study, the levels of education did not have an association with malnutrition. However, in several studies (
14,
28), the low level of education has been reported as a factor associated with malnutrition. In addition, several studies have also revealed that although the prevalence of moderate (
4) and severe (
4,
5) malnutrition in patients with a high level of education were less than those with low education, no association was found between malnutrition and education. The high rate of malnutrition in people with low education levels can be linked to an inadequate awareness about the nutritional needs during disease, improper food habits, and culture. Further studies are needed to determine whether socioeconomic factors such as education levels are effective in malnutrition.
This study has some limitations including non-compliance of patients; lack of measurement of other anthropometric parameters (such as triceps skinfold (TSF), mid-arm muscle circumference (MAMC), and biochemical data (such as prealbumin, C-reactive protein (CRP), creatinine height index (CHI)); limited the number of hospital wards; thus the results could not be representative of patients information in other hospitals.
The strength of the study was the use of MUST’ as a nutrition screening tool, which has predictive validity in elderly hospitalized patients, even in those who can't be weighted.
5.1. Conclusions
Overall, findings revealed that almost half of the patients admitted need nutritional supports. Since, nutritional status may be deteriorated during hospital stay, it is suggested that nutritional screening, by a simple procedure, are applied at admission to hospital.