Clinical efficacy of combined therapy with peritoneal dialysis and hemodialysis

Combined therapy with peritoneal dialysis (PD) and hemodialysis (HD) represents a treatment option for PD patients who cannot maintain adequate solute and fluid removal. It has rapidly gained popularity in Japan, and 15 years of accumulated experiences is available. Serum creatinine, serum β2 microglobulin (β2m), body weight, and blood pressure decreased, whereas hemoglobin increased after initiating combined therapy. These results indicated that both adequacy of dialysis and hydration status were significantly improved. In addition, dialysate-to-plasma ratio of creatinine (D/P Cr) as obtained from peritoneal equilibration test (PET) was decreased, probably due to the functional and histological improvements of the peritoneal membrane. Combined therapy may have a good impact on the prevention of cardiovascular disease through reduction of blood pressure, correction of fluid overload, and improvement of left ventricular hypertrophy. Quality of life may improve as a result of decreases in uremic symptomatology and freedom from bag exchanges. On the other hand, combined therapy with PD and HD has some concerns. A reduction in urine volume during combined therapy indicates a decline in residual renal function, and may have potential negative impacts on life expectancy. Furthermore, induction of combined therapy would increase the overall duration of PD treatment and susceptibility to peritonitis. We have to pay attention to the development of encapsulating peritoneal sclerosis, as the most serious complication of PD, because both prolonged PD duration and increased number of peritonitis episodes are independent risk factors. Here, we propose criteria for the indication and discontinuation of combined therapy. Under these criteria, Kt/V, serum β2m, and uremic symptoms including nutritional status, erythropoiesis-stimulating agent-hyporesponsive anemia, and restless legs syndrome were used as markers of dialysis adequacy. On the other hand, higher blood pressure, heart enlargement or pleural effusion on chest X-ray, and persistent peripheral edema were used as markers of hydration status. Further studies, particularly prospective cohort studies with a large group of cases, are needed to confirm the clinical efficacy of combined therapy with PD and HD. © 2016 The Author(s).