Risk factors of reduced functional capacity of ICU patients at hospital discharge

Introduction

Increasing interest has been focused on survival beyond the ICU stay. Functional capacity, as described by simple everyday activities, can be severely compromised after ICU and hospital stay. Our aim was to identify patients' risk factors for reduced functional capacity at hospital discharge on the first 2 days after ICU admission.

Methods

A prospective cohort of medical and surgical patients admitted to a private ICU from September to December 2008 was studied. The analyzed demographic data were age, gender, height and weight (body mass index (BMI)). Functional capacity was measured by the Barthel Index (BI), described as totally dependent, partially dependent or independent capacity for feeding, bath, self-care, dressing, urinary and fecal continence, bathroom use, bed to chair transference, short walking, and climbing stairs. The BI was scored from 0 to 100 points, and was calculated on ICU admission and immediately before hospital discharge. A reduced BI was defined as less than 80 points. The admission diagnosis was classified by organ/tissue systems (respiratory, cardiovascular, neurological, gastrointestinal, renal, orthopedic, gynecologic, head/neck surgery, trauma, and infection/sepsis). Acute severity of illness was calculated (SAPS II and SOFA scores) on day 1 of admission. Comorbidities were classified as the Charlson Index, and recent (<5 years) neoplasm was separately analyzed. Use of mechanical ventilation (MV) was considered a unique risk factor. Numeric data were described as median (interquartile 25 to 75 interval) or absolute values and percentage. Univariate analysis was conducted initially for all research variables according to a BI cutoff of 80 points. Logistic regression was performed with inclusion of variables with P < 0.10 in bivariate analysis.

Results

A total of 374 patients were admitted to the ICU in the study period. The median age was 68.5 years (57 to 79), 47% were male. BMI was 25 (22 to 28). The ICU length of stay was 2 days (1 to 3), with 2% ICU mortality. There was a predominance of surgical patients (69%). The most common causes of ICU admission were respiratory, cardiovascular, gastrointestinal and orthopedic diseases. The SAPS II score was 22 points (15 to 28), and SOFA on day 1 was 1 (0 to 2). Any comorbidity was present in 194 (52%) patients, with a Charlson Index of 1 point (0 to 2). Recent neoplasm was present in 97 (26%) cases. MV was necessary for 30 (8%) patients. The BI was calculated for 318 patients who were discharged from hospital: ICU admission index 80 (70 to 100) and discharge 100 (80 to 100). The most common disabilities on ICU admission were dressing (19%), bathroom use (18%), bed to chair transference (54%), short walking (55%), and climbing stairs (99%). At hospital discharge, disabilities remained significant for bathroom use (19%), bed to chair transference (42%), short walking (41%), and climbing stairs (39%). Risk factors for a BI at discharge less than 80 points were: age >65 years (odds = 3.18; 95% CI = 1.75 to 5.79), SAPS II >22 points (2.15; 1.25 to 3.67), use of MV (2.67; 1.03 to 6.91), medical type of admission (1.76; 0.99 to 3.11), orthopedic admission (2.59; 1.34 to 5.04), and initial BI <80 points (24.11; 11.76 to 49.42). After logistic regression, the initial BI, age, and orthopedic admission diagnosis were significant predictors for reduced discharge BI.

Conclusion

An initial worse functional capacity, age and orthopedic diagnosis are strong predictors for a reduced BI at hospital discharge.