Validity of the Spanish 8-item short-form generic health-related quality-of-life questionnaire in surgical patients: a population-based study.

ABSTRACT

BACKGROUND: Health-related quality of life is usually reported for specific rather than heterogeneous populations such as those treated in routine anesthesia practice. The 8-item short-form generic health-related quality-of-life questionnaire (SF-8) is a candidate instrument for this setting. The authors evaluated the feasibility, reliability, validity, and responsiveness to change of the Spanish version of SF-8 in a population-based surgical cohort. METHODS: Recruiting patients from a large population-based study of risk factors for pulmonary complications, before surgery, the authors administered the 1-week recall SF-8 to 2,991 patients undergoing nonobstetric elective or emergency surgery in 59 hospitals, each of which collected data on seven randomly assigned days in 2006. The SF-8 was administered again 3 months later. Reliability was evaluated using the Cronbach alpha coefficient and validity by comparing physical and mental component summary SF-8 scores with clinical variables. Responsiveness after surgery was evaluated using the standardized response mean. RESULTS: Cronbach alpha for the overall test was 0.92. Physical and mental component summary scores and all individual scores were lower (worse quality of life) in women (P < 0. 01) and decreased with age (P < 0.01). Preoperative scores were lower for those in worse clinical condition (higher body mass index, American Society of Anesthesiologists physical status class, or surgical risk scores), with preoperative respiratory symptoms, and in emergency situations (P < 0.01). The standardized response mean ranged from 0.1 to 0.5. CONCLUSIONS: The SF-8 is a feasible, reliable, valid, and responsive instrument for assessing health-related quality of life in a broad-spectrum surgical population.