Cognitive impairment linked to early death in haemodialysis patients

Haemodialysis patients with cognitive impairment are at risk of premature mortality, which does not appear be associated with education, according to data from the COGNITIVE-HD Study.

The study included 676 adult haemodialysis patients (median age, 70.9 years; 38.8 percent female) treated in 20 Italian dialysis clinics. All patients underwent a neuropsychological assessment to determine cognitive function across the following domains: memory, attention, executive function, language and perceptual-motor function.

Of the 664 patients with complete data, 527 (79.4 percent) had cognitive impairment. A total of 206 deaths occurred during a median follow-up of 3.3 years (1,874 person-years).

Nested multivariable Cox regression models showed that patients with any cognitive impairment had a 77-percent higher risk of mortality relative to those without impairment (hazard ratios [HR], 1.77, 95 percent CI, 1.07–2.93). The corresponding HRs associated with one, two and three-to-five domains impaired were 1.48 (0.82–2.68), 1.88 (1.01–3.53) and 2.01 (1.14–3.55).

On the other hand, every standard deviation increase in global cognitive function score was associated with a 32-percent reduction in mortality risk (HR, 0.68, 0.51–0.92).

Compared with patients with primary or lower education, those with lower secondary or upper secondary/higher had HRs for mortality of 0.79 (0.53–1.20) and 1.13 (0.80–1.59), respectively. The cognition-by-education interaction was not significant (p=0.7).

The study was limited by potential selection bias from nonparticipation, lack of data on cognitive decline and the inability to control for other socioeconomic factors.