Quality of life (QOL) is an important metric of high-quality dialysis care. QOL is commonly measured by the Short Form 36 Questionnaire (SF-36), which provides two summary scores: a mental component score (MCS) and a physical component score (PCS). Poor QOL is associated with mortality in dialysis patients. Small studies show that changes in QOL also predicts mortality. We investigated whether changes in QOL over time are associated with mortality in a large cohort of maintenance hemodialysis patients.
This retrospective study was conducted in 1017 outpatient dialysis facilities. Over 10,000 hemodialysis patients completed two SF-36 surveys. We compared 1-year morality rates in those whose MCS or PCS increased or decreased ±5 vs. those whose did not.
For those who completed two surveys, mean score for PCS was unchanged, whereas MCS increased slightly (48.6 vs. 48.9, p = 0.05). Individual patients, however, showed marked variation. On the second survey, more than half of patients demonstrated a ± 5 point change in the PCS and/or MCS. After multivariate adjustment, a ≥ 5 decrease in MCS was associated with an increase in mortality (HR = 1.33, 95 % CI 1.18, 1.50).
Clinicians should be aware that many patients experience a significant change in both the MCS and PCS on dialysis. A MCS decrease of ≥5 was associated with increased mortality. More study is needed to determine whether this is a causal relationship. Physicians should evaluate root causes and seek to mitigate declines in QOL whenever possible.