Continued transplant immunosuppression may prolong survival after return to peritoneal dialysis: results of a decision analysis.

Background: Patient survival is prolonged in those with residual renal function. The risks of opportunistic infection and malignancy militate against a widespread policy of maintaining immunosuppression in those returning to peritoneal dialysis after a failed allograft. We set out to test the hypothesis that patients returning to peritoneal dialysis after a failed transplant benefit from continued immunosuppression.

Method: A decision analytic model comparing the use of immunosuppression after transplant failure and return to peritoneal dialysis with immunosuppressive withdrawal. Two assumptions were made: that the survival benefit reported in patients with a transplant kidney was the same as that expected from a native kidney with a similar glomerular filtration rate (GFR) and that the risks of carcinoma and opportunistic infections were equal to that of the general population if immunosuppressive therapy was discontinued. Probabilities were obtained from the literature, from an administrative database, and from the rate of GFR decline seen in our own unit in patients returning to dialysis who had been discontinued from their transplant immunosuppressive medication.

Results: Life expectancy was prolonged from 5.3 years to 5.8 years when immunosuppression was continued in patients who returned to dialysis after chronic allograft failure. A higher survival benefit was seen at higher levels of additional GFR. A benefit from continued immunosuppressive therapy was seen for all values of additional GFR greater than 15 L/wk. All dialysis and renal clearances have been expressed as L/wk. The conversion factors for conversion to mL/s and mL/min are 605 and 10.1.

Conclusion: The data suggest that there may be a survival advantage in maintaining patients on long-term immunosuppressive function even after they return to peritoneal dialysis after allograft failure.