Effect of high cut-off dialysis for acute kidney injury secondary to cast nephropathy in patients with multiple myeloma: a systematic review and meta-analysis

Abstract

ABSTRACT Background Acute kidney injury (AKI) caused by cast nephropathy is associated with increased morbidity and mortality among patients with multiple myeloma (MM). High cut-off haemodialysis (HCO-HD) has proven to be effective in the removal of serum light chains but the effect on clinical outcomes, especially renal recovery, remains uncertain. Methods A systematic review and meta-analysis were performed examining all randomized controlled trials (RCTs) and observational studies (OBSs) assessing the effect of HCO-HD on clinical outcomes of patients with MM complicated by cast nephropathy–induced severe AKI. The primary outcome was all-cause mortality at the end of the study. The secondary outcomes included all-cause mortality at 12\u2009months, HD independence and serum kappa and lambda light chain reduction. Pooled analysis was performed using random effects models. Results We identified five studies, comprising two RCTs and three retrospective cohort studies, including 276 patients with a mean follow-up of 18.7\u2009months. The majority of the studies were of suboptimal quality and underpowered. Compared with patients treated with conventional HD, HCO-HD was not associated with a survival benefit at 12\u2009months {five studies, 276 patients, relative risk [RR] 1.02 [95% confidence interval (CI) 0.76–1.35], I2 =\u200933.9%} or at the end of the studies at an average of 34\u2009months [five studies, 276 patients, RR 1.32 (95% CI 0.71–2.45), I2 =\u200962.0%]. There was no difference in HD independence at 90\u2009days [two trials, 78 patients, RR 2.23 (95% CI 1.09–4.55)], 6\u2009months [two studies, 188 patients, RR 1.19 (95% CI 0.68–2.06)] or 12\u2009months [two studies, 188 patients, RR 1.14 (95% CI 0.58–2.26)]. Patients receiving HCO dialysis, however, had a greater reduction in serum kappa [two studies, 188 patients, weighted mean difference (WMD) 46.7 (95% CI 38.6–54.7), I2 =\u2009 52.0%] and lambda [two studies, 188 patients, WMD 50.3 (95% CI 21.4–79.3), I2 =\u200995.1%] light chain levels. Conclusion Current evidence from RCTs and OBSs suggests HCO dialysis is able to reduce serum free light chains but makes no significant improvement in all-cause mortality and renal outcomes compared with conventional HD for patients with myeloma cast nephropathy. However, there is a trend towards better renal outcomes with the use of HCO dialysis. The lack of long-term data and the small sample sizes of the included studies limit this analysis. Therefore further large-scale RCTs with longer follow-up are needed to assess the effect of HCO dialysis on clinical outcomes in patients with myeloma cast nephropathy.