Quality of life before intensive care unit admission is a strong predictor of survival

Objective

To examine whether health-related quality of life (HRQOL) before admission to the ICU can be used as a predictor of mortality

Design and methods

A prospective cohort study in an university-affiliated teaching hospital. Patients admitted to the ICU for >48 hours were included. Close relatives completed the Short-form 36 (SF-36) within the first 48 hours of admission to assess the pre-morbid HRQOL of the patient. Mortality was evaluated from ICU admittance until 6 months after ICU discharge. Logistic regression and ROC analysis were used to assess the predictive value for mortality of the first general health question of the SF-36 ('in general would you say the health of your relative is excellent, very good, good, fair or poor'), as well as HRQOL measured by the complete SF-36. The Acute Physiologic and Chronic Health Evaluation (APACHE) II score was used as an accepted mortality prediction model in ICU patients. Three models were constructed including the HRQOL (model A), APACHE II score (model B), or both (model C) to age and gender. Percentages of correct survival/death predictions were calculated.

Results

Four hundred and fifty-one patients were included at admission to the ICU. At 6 months follow-up, 159 patients had died and 40 patients were lost to follow-up. When the general health item was used as an estimate of HRQOL, the area under the curve (AUC) for model A (0.719) was comparable with model B (0.721), and slightly better in model C (0.760). The percentage of wrong predictions was lower in model C (survival 27%; death 37%) compared with model A (30% and 41%). Similar results were found when using the complete SF-36.

Conclusion

This study shows that the pre-admission HRQOL measured with either the one-item general health question or the complete SF-36 are as good in predicting survival/mortality in ICU patients as the APACHE II score and improves prediction slightly when combined. As the one-item general health question is easily and quickly obtained, assessment of HRQOL before admission to the ICU may facilitate the decision process in determining which patients will benefit from ICU treatment.