Introduction: malnourishment, dehydration and dysphagia are common in hospitalized patients both in
Acute and Sub-acute care settings. However, the relationships among these conditions have been poorly
studied and with divergent results. In the absence of these information it appears very difficult to appropriate
manage health-care resources in order to early identify the population at risk of developing negative
outcomes and to develop a prevention program.
This research project was design in order to improve the clinical management of dysphagic, malnourished
and dehydrated patients admitted to the Acute and Sub-acute care Units. In particular, the project was
structured into 3 different phases. In the first one the prevalence of malnutrition, dysphagia and dehydration
at admission in Acute and Sub-acute care settings was analyzed. In the second phase the association between
malnutrition, critical weight loss, dysphagia and dehydration and negative clinical outcomes was studied.
Finally, in the third phase a statistically-based exploratory analysis (using an unsupervised clustering method)
was used in order to identify the presence of similar phenotypic subgroups of patients according to objective
criteria. In addition, the ability of this classification in predicting negative clinical outcomes was also assessed.
Materials and methods: a total of 686 patients were recruited, 483 of them were admitted to the Acute care
Unit (Stroke-Unit), while 203 were admitted to the Sub-acute care Unit. Information regarding age, gender,
weight, height, presence of aphasia and dysarthria, severity of stroke (only in patients admitted to the Acute
care Unit), data on functional status activity of daily living, data on oral intake, data on serum analysis (known
or suspected to be related to the presence of dysphagia, dehydration and malnutrition), presence of
swallowing disorders, data on hydration level, presence of undernutrition were collected at admission in all
the patients.
Student t test and Chi-square test were used to compare the distribution of continuous and categorical data
among patients according to gender and presence of dysphagia. Correlation analysis was performed in order
to evaluate the presence of significant correlations among the collected variables. Kaplan-Meier curves and
Cox\u2019s proportional hazard models were used to assess the impact of malnutrition, critical weight loss,
dysphagia and dehydration on clinical outcomes. Finally, Ward\u2019s minimum-variance hierarchical method was
used in order to generate clusters by placing subjects into groups not defined a priori but according to the
similarity of clinical characteristics.
Results: Patients admitted to the Acute care Unit were found malnourished in 16.2% of cases. Dysphagia was
detected in 24.2% of patients while dehydration was found in 49.7% of cases. As far as it is concerned the
Sub-acute care Unit, dysphagia was reported in 22.2% of cases, malnutrition in 22.2% of cases and
dehydration in 45.8% of cases. A total of 114 patients died during the follow-up period. One-hundred-two
were admitted to the Acute care Unit, while 12 were admitted to the Sub-acute care Unit. In both group no
significant association between malnutrition and dehydration and mortality or pulmonary complications was
found. On the other hand, dysphagia significantly affected survival. In the Acute care Unit 33 out of the 117
patients with dysphagia died during the 6 months follow-up; while in the Sub-acute care Unit 8 out of the 45
patients with dysphagia died during the 6 months follow-up. In addition, the presence of dysphagia
significantly increased the risk of developing pulmonary complications (Odds Ratio = 5.493; p = 0.007 in Acute
care settings and Odds Ratio = 2.809; p = 0.029 in Sub-acute care settings). Also critical weight loss
significantly affected survival and increased the risk of develop pulmonary complications both in Acute and
in Sub-acute care settings. Patients with both critical weight loss and dysphagia had a higher mortality risk
than patients with critical weight loss but without dysphagia or patients with dysphagia but without critical
weight loss (Odds Ratio = 4.943; p = 0.019 in Acute care settings and Odds Ratio = 2.732; p = 0.032 in Subacute
care settings). Using the clustering approach, a dendrogram was generated and a 4-cluster reduction
was chosen to describe the results. Patients in different clusters demonstrated significant differences both
in the results of continuous and categorical data. In addition, significant differences among clusters were also
found in survival and in the risk to develop pulmonary complications. In particular, patients of cluster 2 died
more frequently than patients in the other clusters (p = 0.019), while pulmonary complications were more
frequently in patients of cluster 1 and 2 (p = 0.021).
Discussion: the prevalence of malnutrition, dehydration and dysphagia was high, both in Acute and Subacute
care settings. Interestingly, malnutrition and dehydration did not influence the occurrence of negative
clinical outcomes. On the other hand, dysphagia and critical weight loss significantly affected survival and
occurrence of pulmonary complications. In particular, dysphagic patients who experienced a critical weight
loss had the poorest prognosis. The unsupervised statistical methods based upon hierarchical clustering was
able to classify patients into 4 clusters which described patients who shared common clinical features. Even
if it is unlikely that these clusters represent distinct pathophysiologies, patients in different clusters have
significantly different prognoses. It is possible that the application of unsupervised clustering method in the
classification of hospitalized patients could provide interesting prognostic information