Opacity of big toenail predicts poor prognosis in patients with end-stage renal disease on hemodialysis

Background The impact of nail abnormalities on prognosis in hemodialysis patients is unknown. This study investigated whether toenail opacity as a readout of nail abnormalities predicted prognosis in hemodialysis patients. Methods In this observational study, 494 eligible hemodialysis patients who received hemodialysis at Oyokyo Kidney Research Institute between September 2010 and December 2015 were included. The presence of nail abnormalities was objectively evaluated by big toenail opacity ratio measurement. Primary endpoint was overall survival, and secondary endpoints were lower limb amputation and determination of risk factors for poor prognosis among patient demographics, comorbidities, blood tests, and big toenail opacity. Overall survival and lower limb survival were evaluated using the Kaplan–Meier method with log-rank test. Multivariate Cox regression analyses assessed predictors for poor prognosis. Results Big toenail opacity was found in 259 (52%) patients. Patients with big toenail opacity were significantly older, had shorter duration of dialysis, higher prevalence rates of diabetes mellitus (DM), cardiovascular disease (CVD), and higher mortality rates than those without opacity. Presence of big toenail opacity predicted poor prognosis for both overall and lower limb survival. Multivariate Cox regression analyses revealed serum albumin, the presence of DM and big toenail opacity were independent risk factors for both poor overall and lower limb survivals. Conclusion The prevalence of big toenail opacity was high in hemodialysis patients. Despite the short observation period, our findings indicated that big toenail opacity had significant predictive power for poor overall and lower limb survival.