Five-year stability in associations of health-related quality of life measures in community-dwelling older adults: the Rancho Bernardo Study

OBJECTIVE: This study examines the five-year stability of the association of SF-12 and SF-6D scores with scores on the longer SF-36 and its domains in community-dwelling older men and women. METHODS: Participants were 653 men and 917 women aged 50 and older who completed mailed surveys of HRQOL (1995, 2000). SF-36 physical (PCS) and mental (MCS) component scores, domain scores; SF-12 PCS and MCS scores; and SF-6D scores were computed. RESULTS: Average age in 1995 was 68.2 ± 10.7 for men and 69.8 ± 11.3 for women. In 1995 and 2000, men had significantly higher scores on all measures (P’s < 0.001). Sex-specific Pearson correlations of SF-12 PCS and MCS scores with SF-36 PCS and MCS scores ranged from 0.91 to 0.97 (P’s < 0.000). Health utility scores (SF-6D) were also associated with SF-36 PCS and MCS scores, but correlations were lower, ranging from 0.61 to 0.79 (P’s < 0.000). Age-stratified comparisons of 5-year change scores for SF-36 PCS showed significant declines in physical health for both men and women within all four age-groups (50–59, 60–69, 70–79, 80+) with steepest declines in the oldest age-group (age 80+). Over time, mental health scores showed significant modest improvement in the younger age-groups but declines in men >70 and women >80 years. The SF-6D scores improved somewhat for the youngest men and women but mean change scores declined for the other age-groups. CONCLUSION: Similar conclusions would result using either instrument SF-12 or SF-36. However, SF-6D and SF-36 assess, at least in part, different underlying aspects of HRQOL. Both age and sex impact HRQOL.