RESUMO
BACKGROUND: Hypercalcemia is highly prevalent in kidney transplant recipients with hyperparathyroidism. However, its long-term impact on graft function is uncertain. METHODS: We conducted a prospective cohort study investigating adverse graft outcomes associated with persistent hypercalcemia (free calcium > 5.2 mg/dL in ≥ 80% of measures) and inappropriately elevated intact parathyroid hormone (> 30 pg/mL) in kidney transplant recipients. Asymptomatic mild hypercalcemia was monitored unless complications developed. RESULTS: We included 385 kidney transplant recipients. During a 4-year (range 1-9) median follow-up time, 62% of kidney transplant recipients presented persistent hypercalcemia. Compared to kidney transplant recipients without hypercalcemia, there were no significant differences in graft dysfunction (10% vs. 12%, p = 0.61), symptomatic urolithiasis (5% vs. 3%, p = 0.43), biopsy-proven calcium deposits (6% vs. 5%, p = 1.0), fractures (6% vs. 4%, p = 0.64), and a composite outcome of urolithiasis, calcium deposits, fractures, and parathyroidectomy indication (16% vs. 13%, p = 0.55). In a subset of 76 kidney transplant recipients, subjects with persistent hypercalcemia had higher urinary calcium (median 84 [43-170] vs. 38 [24-64] mg/day, p = 0.03) and intact fibroblast growth factor 23 (median 36 [24-54] vs. 27 [19-40] pg/mL, p = 0.04), and lower 25-hydroxyvitamin D levels (11.3 ± 1.2 vs. 16.3 ± 1.4 ng/mL, p < 0.001). In multivariate analysis, pretransplant intact parathyroid hormone < 300 pg/mL was associated with a reduced risk of post-transplant hypercalcemia (OR 0.51, 95% CI 0.32-0.80). CONCLUSIONS: Long-term persistent mild hypercalcemia (tertiary hyperparathyroidism) was frequent in kidney transplant recipients in our series. This condition presented with lower phosphate and 25-hydroxyvitamin D, and higher urinary calcium and intact fibroblast growth factor 23 levels compared to kidney transplant recipients without hypercalcemia, resembling a mild form of primary hyperparathyroidism. Despite these metabolic derangements, the risk of adverse graft outcomes was low.
RESUMO
BACKGROUND: In patients with autosomal dominant polycystic kidney disease (ADPKD), there is limited evidence of the rate of cyst progression after kidney transplantation. AIMS: To compare the height-adjusted total kidney volume (Ht-TKV) before and after transplantation in kidney transplant recipients (KTR) with -ADPKD. MATERIALS AND METHODS: Retrospective cohort study. The estimate of Ht-TKV was calculated by the ellipsoid volume equation using measurements from CT or yearly MRI scans before and after transplantation. RESULTS: We included 30 patients with -ADPKD who underwent kidney transplantation (age 49 ± 10.1 years, 11 (37%) females, dialysis vintage 3 (1 - 6) years, and 4 (13%) underwent unilateral nephrectomy during the peritransplant period). The median follow-up time was 5 years (range 2 - 16 years). Transplantation was associated with a significant decrease in Ht-TKV after transplantation in 27 (90%) KTR. Median Ht-TKV decreased from 1,708 (IQR 1,100 - 2,350) mL/m to 710 (IQR 420 - 1,380) mL/m after 6 years of follow-up (p < 0.001), with a mean Ht-TKV change rate per year after transplantation of -1.4, -11.8, -9.7, -12.7, -7.0, and -9.4% after 1, 2, 3, 4, 5, and 6 years, respectively. Even in 2 (7%) KTR without regression, the annual growth was < 1.5% per year after transplantation. CONCLUSION: Kidney transplantation reduced Ht-TKV after the first 2 years of transplantation, and this decline was continuous for more than 6 years of follow-up.
