Pre-admission functional status and outcome in medical intensive care

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Introduction

Guidelines for intensive care unit (ICU) admission recommend taking the premorbid functional status and comorbidity of patients into consideration when selecting those who are likely to benefit from ICU care [1]. We analyzed the prognostic value of pre-admission functional status, comorbidity and daily APACHE II scores in medical ICU patients.

Patients and methods

All patients ≥ 18 years of age who stayed >24 h in our non-coronary medical ICU were eligible for inclusion. Functional status referred to the two months prior to admission and was assessed using the domains of basic physiologic activities and activities of daily life of the PAEEC quality of life questionnaire [2]. Comorbidity was categorized using the Charlson Index (CI) [3]. ICU, hospital and six-month follow-up mortality rates were documented. Statistical analysis used the cox model for censored data.

Results

During the 12-month study period, 325 patients were included. 55% were male, mean age was 58± 17 (± SD) years, range 19-95 years. Mean ICU length of stay was 10.4± 15 days, range 2-127 days. Mean APACHE II score (first 24 h) was 23± 10, range 0-51. 75% of our patients had one or more chronic diseases, mean CI was 2.4± 1.9, range 0-11. Functional status was reduced in 80% of our patients, with 40% of them demonstrating severe impairments. Cumulative mortality rates were: ICU 24%, hospital 34.5%, six-month follow-up 40.3%. One patient was lost to follow-up. Multivariate analysis showed that pre-admission functional status (ICU/hospital mortality: P=0.008/P=0.0009), CI (P=0.003/P=0.0005) and APACHE II score (P=0.012/P=0.012) had an highly significant association with ICU and hospital mortality.

Conclusion

In our population of critically ill medical patients with a high rate of preexisting chronic diseases, pre-admission functional status and comorbidity are independent variables with a highly significant association with on-unit and hospital mortality.