Applicability of laboratory deficit-based frailty index in predominantly older patients with end-stage renal disease under chronic dialysis: A pilot test of its correlation with survival and self-reported instruments

Aim Laboratory deficit-based frailty index (LFI) exhibited outcome-prediction ability in the elderly, but not in those with end-stage renal disease (ESRD). We hypothesized that LFI results might have outcome correlation and correlate closely with other instruments in ESRD patients. Methods We prospectively enroled ESRD patients between 2014 and 2015 and administered self-report frailty instruments (Strawbridge questionnaire, Edmonton frail scale (EFS), Groningen frailty indicator (GFI), Tilburg frailty indicator, G8 questionnaire and FRAIL scale), and Cardiovascular Health Study (CHS) scale, with two types of LFI calculated. They were followed up until June 30, 2017. Correlations between the results of six instruments, CHS scale, and those of LFI were identified, followed by Kaplan-Meier survival analyses and logistic regression analyses to compare those with high and low LFI. Results The frailty prevalence was 33.3% (CHS), 78.8% Strawbridge questionnaire, 45.5% (EFS), 57.6% (GFI), 27.3% (Tilburg frailty indicator), 84.8% (G8) and 18.2% (FRAIL) among ESRD participants. LFI-1 results were significantly correlated with those of LFI-2 (P < 0.01), EFS (P = 0.04) and GFI (P < 0.01), while LFI-2 results were not. Those with CHS or GFI-identified frailty had significantly lower 1,25-(OH)(2)-D levels than those without. After 32.3 +/- 5.4 months, patients with high LFI-1 scores, but not LFI-2, had a significantly higher mortality than those with lower scores. GFI and EFS scores were also independently associated with LFI-1, while CHS scores exhibited borderline association only. Conclusion Among a group of predominantly older ESRD patients, LFI differentiates patients with good and poor outcomes, supporting its applicability in these patients.