Furosemide and albumin for the treatment of nephrotic edema: a systematic review

Edema is one of the cardinal clinical features of nephrotic syndrome (NS). It may vary from mild periorbital edema to severe generalized edema (anasarca). In patients where edema does not improve with prednisone therapy, the most common supportive medications are diuretics and albumin. However, due to the complex pathophysiology of edema formation in NS patients resulting in intravascular normovolemia or hypovolemia, optimal therapy for edema is still debated. We conducted a systematic review with the objective of evaluating the change in urine volume and urine sodium excretion after treatment with furosemide only versus furosemide with albumin in edematous patients with NS.(1) To evaluate efficacy of furosemide alone versus furosemide with albumin in the treatment of nephrotic edema in adults and children. (2) To compare the harms and benefits of different doses of furosemide for treating nephrotic edema.The search included all randomized or quasi-randomized controlled trials in English and French using MEDLINE, Embase, and CENTRAL Trials Registry of the Cochrane Collaboration using the Ovid interface. ClinicalTrials.gov and the International Clinical Trials Registry Platform were also searched.We included all RCTs and randomized cross-over studies in which furosemide and furosemide plus albumin are used in the treatment of children or adults with nephrotic edema. We excluded patients with hypoalbuminemia of non-renal origin and severe chronic kidney disease (CKD) with a glomerular filtration rate below 30 ml/min/1.74 m2 and patients with congenital NS.All abstracts were independently assessed by at least two authors to determine which studies met the inclusion criteria. Information on study design, methodology, and outcome data (urine volume, urine sodium excretion, adverse effects) from each identified study was entered into a separate data sheet. The differences in outcomes between the types of therapy were expressed as standardized mean difference (SMD) with 95% confidence intervals (CI).The search yielded 525 records, and after screening, five studies were included in the systematic review and four of those studies in the meta-analysis. One study had high risk of bias and the remaining three studies were deemed to have some concerns. Urine excretion was greater after treatment with furosemide and albumin versus furosemide (SMD 0.85, 95% CI = 0.33 to 1.38). Results for sodium excretion were inconclusive (SMD 0.37, 95%CI = - 0.28 to 1.02).The current evidence is not sufficient to make definitive conclusions about the role of albumin in treating nephrotic edema. High-quality randomized studies with adequate samples sizes are needed. Including an assessment of intravascular volume status may be helpful.Prospero: CRD4201808979. https://www.crd.york.ac.uk/PROSPERO A higher resolution version of the Graphical abstract is available as Supplementary information.