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Primary hyperoxaluria (PH) is a heterogeneous disease with a variable age of onset and a variable progression into kidney failure. Early diagnosis is mandatory to avoid the damaging effects of systemic calcium oxalate deposition. In 1997, we initiated a nationwide survey of American nephrologists to ascertain epidemiological data and current practices. PH was reported in only 102 patients, with PH I in 79 and PH II in 9; 14 patients were not classified. Most patients were Caucasian (84%). Main symptoms at diagnosis were urolithiasis (54.4%) and nephrocalcinosis (30%). A significant delay of diagnosis was seen in 42% of patients and 30% of patients were diagnosed only at end-stage renal disease (ESRD). Diagnosis was usually based on history and urinary oxalate excretion. Glycolate and l-glyceric acid excretion were rarely determined. To determine the enzyme defect, a liver biopsy was performed in 40%. Even at ESRD, only 56% of patients received an adequate diagnostic work-up. Half of the patients showed 'good' or 'fair' pyridoxine sensitivity. In addition to B[sub 6], most patients received either citrate or orthophosphate. Kidney transplantation (KTx) failed in 19 of 32 transplants (n=27 patients) and was due to recurrent oxalosis in 8 transplants. Liver Tx was performed after KTx in 5 patients (1 patient died). Combined liver-kidney Tx in 21 patients (in 9 patients after failure of KTx) achieved good organ function in 13 patients; 7 patients, however, died shortly after transplantation. In conclusion, the time between first symptom and diagnosis of PH must be minimized, and the diagnostic procedures have to be improved. The cases of unclassified hyperoxaluria suggest the possibility of additional type(s) of PH. As isolated KTx failed in 59% of patients, combined liver-kidney Tx seems to be the better choice in place of isolated KTx as the primary transplant procedure. [ABSTRACT FROM AUTHOR]

Transplantation for primary hyperoxaluria in the United States. Background. Transplantation (TX) has become an acceptable treatment for renal failure in primary hyperoxaluria (PH). We have analyzed data from three U.S. sources to estimate the success or failure of different modes of management in PH patients. Methods. The United States Renal Data System (USRDS) tapes provided coded medical record data, with PH assigned to 235 patients from 1974 to 1996. Another 45 patients were found from USRDS hospitalization records. We limited patients to those developing end-stage renal disease at <55 years of age after 1984 (95 PH patients). The North American Pediatric Renal Transplantation Cooperative Study (NAPRTCS) identified 34 (11 new) PH patients, and the United Network for Organ Sharing (UNOS) database identified PH in 34 (16 new, 5 more in both UNOS and NAPRTCS) patients. These secondary sources were used to correct some data from the USRDS and to add 32 more patients, with a total of 128 PH patients. Considering kidney TX (KTX) prior to combined kidney/liver TX (K/LTX) as a separate record for some calculations, the total “cases” were 138. Results. By life table analysis, the 94 total TX patient survival was better than for the 34 NoTX patients (P < 0.001). The 52 KTX patients' survival was better than either the 32 primary K/LTX (P < 0.001) or the 10 K/LTX that following KTX (P < 0.001). The 62 KTX cases' survival was better than the 42 K/LTX cases (P < 0.005), which did not differ from the 34 NoTX (P < 0.67). The overall survival of these 62 KTX patients was 76%. The survival of 42 K/LTX was 69%, and the survival of 34 NoTX patients was 44%. Kidney graft life table projected survival curves for TX patients did not differ between K/LTX (56% at 6 years) and isolated KTX (51% at 6 years, 35% at 10 years, P < 0.91). Conclusion. KTX offers better patient survival in the United States then either K/LTX or NoTX. Graft survival does not differ between KTX... [ABSTRACT FROM AUTHOR]