Which Domains of Health Status Predict Mortality? A Longitudinal Population-Based Study

A number of studies confirm that overall measures of health-related quality of life (HRQL), such as the Health Utilities Index Mark 3 (HUI3), are predictive of mortality (Kaplan et al 2007). This study examined which specific domains of HUI3 (vision, hearing, speech, ambulation, dexterity, emotion, cognition, and pain and discomfort) were associated with mortality risk. Data derived from the Longitudinal Canadian National Population Health Survey, consisting of 12,375 women and men aged 18 and older. HUI3 was measured at baseline in 1994/1995. Cox proportional hazards regression models were applied to estimate mortality risks over 12 years. Of the eight domains examined, ambulation (Hazards Ratio [HR] = 0.16; 95% Confidence Interval [CI] = 0.06 – 0.39) and hearing (HR = 0.19; 95% CI = 0.06 – 0.60) were significantly associated with an elevated risk of mortality after controlling for an array of potential confounders. This research indicates that ambulation and hearing at baseline are predictive of subsequent mortality. The finding regarding the predictive ability of ambulation is consistent with previous studies; however, the result concerning hearing is novel. It is possible that hearing loss is a marker of neurological decline. Furthermore, hearing loss may contribute to social isolation and subsequent declines in physical and emotional health. This research emphasizes the need to examine further the underlying mechanisms of the association between ambulation or hearing and mortality risks.