Factors predicting mortality in elderly patients admitted to a Moroccan medical intensive care unit

Introduction. There has been a notable increase in the incidence of elderly patients being admitted to intensive care units (ICUs), globally and in Morocco. Studies on the diagnosis and management of ICU patients often exclude subjects with multiple co-morbidities or those older than 80 years. However, as the world's population becomes increasingly old and ill, this subset will require ICU admission more frequently and their management will pose a serious challenge to the intensivists treating them. There are no studies in the current medical literature from low- or middle-income countries assessing the outcome of elderly patients admitted to ICUs. Specifically, little is known about the outcome of elderly patients admitted to ICUs in Morocco. Aims. The aims of the present study were to analyse the characteristics of elderly Moroccan patients ( aged >= 65 years) admitted to a medical ICU, and to identify factors predicting ICU mortality. Methods. This was a retrospective study conducted in the medical ICU of a Moroccan university hospital. All elderly patients (>= 65 years) with complete records were included, whatever their length of stay. Baseline characteristics, clinical parameters and severity of illness were recorded at admission. Patients were grouped according to their survival status using logistic regression analysis. Results. During the study period, 1 072 patients were admitted to the ICU, of whom 16.6% (n=179) were aged >65 years and had complete records. Fifty-five per cent (n=98) were men. The median age was 70 years (interquartile range 67 - 75 years). The overall ICU mortality was 44.7%, and 64% of deaths occurred within 5 days of admission. On univariate analysis, the factors predicting mortality were alcohol misuse (p=0.09), pneumonia (p <= 0.001), shock (p=0.001), dehydration (p=0.007), urine output <= 0.5 ml/kg/h (p=0.003), serum urea level >16.6 mmol/l (p=0.01), serum creatinine level >159 mu mol/l (p=0.005), and an abnormality on the chest radiograph (p=0.01). The Sequential Organ Failure Assessment (SOFA) score was the most accurate predictor of ICU mortality in this group of elderly patients, with an area under the curve (AUC) of 0.775 (standard deviation (SD) +/- 0.036). The Acute Physiology and Chronic Health Evaluation II (APACHE II) score also performed adequately (AUC 0.757; SD +/- 0.037), but the Simplified Acute Physiology Score II (SAPS II) and Logistic Organ Dysfunction System (LODS) scores were not useful in this group. Two parameters significantly associated with mortality risk were shock (odds ratio (OR) 11.5, 95% confidence interval (CI) 3.7 - 35.7; p<0.001) and pneumonia (OR 3.13, 95% CI 1.5 - 6.2; p<0.001). Conclusion. Admission of aged patients to the ICU raises important medical, ethical, sociological and economic questions. Our findings suggest that severity of illness, shock and pneumonia on ICU admission were the independent risk factors associated with raised mortality, 64% of which occurred within 5 days of ICU admission.