Cognitive impairments hound some haemodialysis patients

Subjective cognitive complaints (SCC) that qualify as clinically relevant cognitive impairments (CI) occur in a quarter of patients on haemodialysis (HD), according to a recent Singapore study. In turn, these complaints compromise patients’ treatment adherence and self-management.

“Although the SCC measure used in the current study lacked sensitivity in detecting objective CIs, findings suggest that cognitive complaints may be a modifiable risk factor of nonadherence in HD patients,” the researchers said.

The study included 305 patients (mean age 53.97 years, 42.6 percent women) on haemodialysis, of whom 23.0 percent reported SCCs that were indicative of clinical impairments. SCCs were quantified using the Kidney Disease Quality of Life Cognitive Function subscale. Scores exceeding 60 points were deemed as probable impairment. [BMC Nephrol 2022;23:363]

Independent samples t-test and Chi-squared analysis revealed that several clinical variables correlated with CI. For instance, those who were diagnosed at an older age were significantly more likely to report CI (p=0.046).

Time on HD also emerged as an important indicator, with probable CI being significantly more common in patients who were newly initiated (≤6 months) than those who had already been on HD for more than 24 months (32.8 percent vs 16.8 percent; p=0.008). SCCs were also more frequently reported among newly initiated patients (p=0.005).

In terms of patient reported outcomes, the researchers found that patients with SCCs indicative of probable CI had significantly worse disease self-efficacy than those who did not meet such criterion (p<0.001). The same was true for treatment self-efficacy (p<0.001).

Self-management, as measured by the Health Education Impact Questionnaire, was also strongly influenced by probable CIs. Patients with such impairments scored significantly lower in the skills and technique acquisition (p=0.001), self-monitoring and insight (p=0.011), and health services navigation (p=0.005) domains of the questionnaire.

Moreover, SCCs indicative of clinical impairment were also associated with worse treatment adherence in general (p=0.018) and particularly during times of difficulty (p=0.014). Meanwhile, depression and anxiety were significantly elevated in those with CIs (p<0.001).

Of note, mediation analysis revealed that cognitive complaints had a significant and indirect effect on medication adherence (b, 0.12, 95 percent confidence interval [CI], 0.06–0.18) and on scores in the Renal Adherence Behaviour Questionnaire (b, 0.21, 95 percent CI, 0.14–0.28).

These results suggested that there was “an indirect effect of SCCs on treatment adherence through treatment self-efficacy,” the researchers explained.

“Future research is needed to confirm these relationships with more comprehensive SCC measures and longitudinal designs,” they said. “This line of research will be the foundation of future interventions or support strategies that target cognitive complaints and SCC-related treatment nonadherence in HD patients.”