Introduction:
Data regarding the effect of pre-admission dietary patterns on length of hospital stay (LOS) are sparse.

Aim:
The aim was to explore potential associations between recent dietary habits (last three months) of inpatients and LOS.

Methods:
Data from 151 hospitalized adult patients (72 women, 121 patients admitted due to cardiovascular disease or stroke) participating in the nutritionDay project were included (years 2013, 2014 and 2016). A 11-item food frequency questionnaire was used to assess dietary habits and then Principal Component Analysis (PCA) was used to derive dietary patterns. The Nutrition Risk Screening 2002 (NRS-2002) was used for the identification of patients at nutritional risk. Multiple linear regression was performed to examine the associations between LOS, dietary patterns, and other covariates.

Results:
Three of the dietary patterns derived by PCA explaining the 55.7% of the total variance were: a) high consumption of vegetables, animal protein and potatoes b) high consumption of alcohol and low consumption of olive oil c) high consumption of legumes, fruits and whole grains. In women, the third pattern was inversely correlated with LOS (B= -1.74, p=0.024) after adjustment for age, risk for malnutrition and underlying diseases. In the same model, age was positively associated with LOS (B= 2.13, p=0.037) (R2 =24.7).

Conclusions:
Adherence to a dietary pattern characterized by high consumption of legumes, fruits and whole grains, for the previous three months before admission, was related to lower LOS, only in women, regardless of nutritional status.