Comparisons Between Oral Pulse Alfacalcidol Therapy and Daily Therapy in Maintenance Hemodialysis Patients with Secondary Hyperparathyroidism: A Randomized, Controlled, and Multicenter Study

Abstract

Objective. To investigate the efficacy and safety of 1α-(OH)-D3 high-dose pulse therapy or daily low-dose therapy in secondary hyperthyroidism in maintenance hemodialysis patients in China. Methods. Maintenance hemodialysis patients of both gender with intact parathyroid hormone (iPTH) level above 200 pg/mL were randomly divided into a pulse group and a daily group. They were treated for 20 weeks, with 2 µg oral Alfacalcidol twice weekly or thrice weekly in the pulse group, and 0.5 µg oral Alfacalcidol per day in the daily group. The therapeutic end point was parathyroid hormone level < 200 pg/mL. The iPTH levels during the study were monitored, and parameters representative of calcium and phosphate metabolism and side effects were also observed. Results. One hundred and fifty-eight patients were initially enrolled, 91 in the pulse therapy group and 67 in the daily therapy group. There was no significant difference in age, hemodialysis duration, proportion of diabetic nephropathy and systemic diseases, proportion of patients who had received active vitamin D therapy previously, mean initial iPTH level (pulse group 570.47 ± 295.86 pg/mL; daily group 498.33 ± 207.84 pg/mL), serum calcium, serum phosphate, alkaline phosphatase (AKP), and albumin between two groups. In the pulse therapy group there were more patients with iPTH levels of 500 ~ 1,000 pg/mL and > 1,000 pg/mL, so stratified analysis according to iPTH level was used. In therapeutic end point, iPTH levels in both groups were significantly lower compared with those before therapy (pulse group 261.29 ± 234.97pg/mL, P < .01; daily group 262.17 ± 274.82 pg/mL, P < .01). After 4 weeks, the ratio of reaching end point in the pulse group was 35.2%, which was significantly higher than that (19.4%) in the daily group (P < .05). More obvious change was seen in the 200 ~ 500 pg/mL subgroup by stratified analysis (P < .05), whereas there was no significant difference between the 500 ~ 1,000 pg/mL and > 1,000 pg/mL subgroup (P > .05). At therapeutic end point, the total ratio of reaching end point did not differ between the two groups, and there were no obvious differences between each subgroup. In the iPTH 200 ~ 500 pg/mL subgroup, mean iPTH%/week in the pulse group was significantly higher than that in the daily group, and no obvious difference was seen in other subgroups. AKP levels decreased significantly in both groups at therapeutic end point (pulse group 98.42 ± 54.52 vs. 74.21 ± 30.68 IU/L, P < .01; daily group 103.3 ± 68.04 vs. 75.40 ± 34.12 IU/L, P < .01). On the 4th week, AKP level in pulse group (82.39 ± 35.23 IU/L) was significantly lower than the initial level (98.42 ± 54.52 IU/L, P < .05), whereas in the daily group there was no difference between each week. The mean serum calcium, phosphate, and [Ca2 +] × [P3 +] levels in both groups did not change greatly. Nine patients in the pulse group (9.9%) and 8 patients in the daily group (11.9%) suffered hypercalcemia at least once. Persistent hypercalcemia occurred in 8 patients in the pulse group (8.8%) and 9 patients in the daily group (13.4%), but the difference in proportion did not show statistical significance. The serum phosphate in the daily group was higher after the therapy (1.74 ± 0.36 vs. 1.89 ± 0.36 mmol/L, P < .05), whereas that in the pulse group remained unchanged. At therapeutic end point, [Ca2 +] × [P3 +] level in the daily group was higher than that before the therapy (48.04 ± 11.71 vs. 55.46 ± 12.66, P < .05), whereas in the pulse group there was no significant difference. Side effects for both groups were minimal and well tolerated. Conclusions. Alfacalcidol [1α-(OH)-D3] has good and safe effects on secondary hyperparathyroidism in maintenance hemodialysis patients. The efficacy and early effects of pulse therapy are superior to those of daily therapy in moderate hyperparathyroidism patients.