Validation of two quality of life questionnaires suitable for intensive care patients

Objective: To validate two instruments measuring quality of life (QOL) suitable for patients admitted to the intensive care unit (ICU): QOL-IT and QOL-SP. Design: Prospective study using patient interviews. Setting: Two four-bed surgical-medical ICUs in a 960-bed teaching hospital. Patients and methods: One hundred seventy-two adult, co-operative patients consecutively admitted to ICU for more than 24 h were interviewed. One year after hospital discharge, 84 survivors were interviewed again. Inter-observer reproducibility was investigated in 36 patients. To validate the instruments, the QOL-IT and QOL-SP scores reported by patients were considered according to the functional limitation evaluated by the interviewer. Moreover, the theoretical prediction that patients with chronic diseases should have a worse QOL before ICU admission than patients with only acute illness was tested. QOL-IT and QOL-SP scores given 1 year after hospital discharge were compared with those recorded at the first interview. Results: Inter-observer reproducibility was excellent. The possible range of QOL-IT is 0-20 and that of QOL-SP 0-29. According to the functional limitation (absent, mild or severe), the median QOL-IT score increased from 3 to 6 to 13 and QOL-SP from 2 to 6 to 12 (p < 0.0001). The patients with chronic diseases gave scores significantly higher than the patients with only acute illness (median QOL-IT 8 versus 3, p < 0.013; QOL-SP 8 versus 4, p < 0.004). The median QOL-IT score changed from 3 to 4 one year after hospital discharge, a difference which is statistically (p < 0.001), but not clinically, significant. The median QOL-SP score was 3 and did not change. Conclusions: QOL-IT and QOL-SP are instruments able to discriminate between different health states.