Session number: 1047
Abstract title: Change in SF-36 and Risk of Hospitalization and Mortality
Author(s):
VS Fan - VA Puget Sound Health Care System, HSR&D NW COE and University of Washington
DH Au - VA Puget Sound Health Care System, HSR&D NW COE and University of Washington
MB McDonell - VA Puget Sound Health Care System, HSR&D NW COE
SD Fihn - VA Puget Sound Health Care System, HSR&D NW COE and University of Washington
Objectives: The SF-36 has been found to predict clinical outcomes. We sought to determine whether changes in SF-36 scores over 1-year were associated with risk of hospitalizations and mortality.
Methods: We analyzed data from patients enrolled in the Ambulatory Care Quality Improvement Project (ACQUIP). 7,702 patients returned the SF-36 at both baseline and 1-year and were then followed for a mean of 617 (sd 148) days. One-year change in the physical (PCS) and mental (MCS) component summary scores was calculated. Cox proportional hazards methods estimated risk of hospitalization and death from any cause after adjusting for baseline demographic factors and comorbidity.
Results: The mean baseline PCS score was 33.4 (SEM 0.13) at baseline, with a mean 1-year decrease of –0.5 (SEM 0.09). The mean MCS score was 46.8 (SEM 0.15) at baseline, with a mean 1-year increase of 1.3 (SEM 0.11). During the follow-up period, there were 522 (6.8%) deaths and 1841 (23.9%) hospitalizations among the cohort. After adjusting for baseline PCS scores, age, VA site, distance to the VA, and comorbidity, a decrease in PCS greater than 5-points was associated with increased risk of both hospitalization and mortality. Compared to those with no change in the PCS, the hazard ratios (HR) for dying or being hospitalized during the subsequent year in patients with a decrease in PCS of more than 10-point were 2.1 (95% CI 1.54-2.74), and 1.6 (1.4-1.9), respectively. A 10-point decrease in the MCS was also associated with an increased risk of both primary outcomes (HR for death, 1.5, 1.1-2.0; HR for hospitalization 1.4, 1.2-1.7). Conversely, an improvement in PCS of 10 points or more was associated with a decreased risk of hospitalizations, (HR 0.76, 0.62-0.92).
Conclusions: After adjustment for baseline scores, 1-year change in PCS scores of the SF-36 is associated with both mortality and hospitalizations. Change in MCS was also associated with death and hospitalization but only when greater than 10 points.
Impact statement: Change in PCS provides important prognostic information over baseline scores alone. This suggests that interventions that stabilize or improve quality of life may be associated with improved long-term outcomes.