Summary of basic characteristics of selected studies for meta-analysis
| Study name | Vitamin D analogs | Number of patients | Administration of Vitamin D analogs and placebos | Patients' status | Measurement of PTH | Measurement of 1,25(OH)2D or 25(OH)D | Mean age (year) | Male (%) |
|---|---|---|---|---|---|---|---|---|
| Massart et al19 | Cholecalciferol | 26 | Cholecalciferol, 25,000 IU, per week orally vs placebo for 13 weeks, then 26 weeks of individualized cholecalciferol prescription based on NKF-KDOQI guidelines. | Adults on maintenance HD for 9–80 months with 25(OH)D levels 30 ng/mL. | Chemiluminescence immune-assays (Liaison,DiaSorin) | Chemiluminescence immunoassays (Liaison,DiaSorin) | 62 | 69.0 |
| Placebo | 29 | 66 | 55.0 | |||||
| Mieczkowski et al8 | Cholecalciferol | 8 | Cholecalciferol was given 2000 IU orally, 3 times a week, during the hemodialysis. The Control group did not receive vitamin D. | Adult patients with serum 25(OH)D20 gnome, HD treatment duration of at least 3 months. | highly sensitive ECLIA (Electrochemiluminescence Immunoassay) | Manual assay system cat. no. AC-62F1 (Immunodiagnostic Systems, Frankfurt, Germany) | 63* | 37.5 |
| Control | 11 | 46* | 63.6 | |||||
| Mose et al20 | Cholecalciferol | 25 | Subjects received 3000 IU(75 μg) cholecalciferol daily or placebo for 6 months | Adults with dialysis for more than 3 months, with no hypercalcemia or malignancy. | NR† | Chemiluminescence immunoassays (Liaison,DiaSorin, Saluggia, Italy) | 68 | 680 |
| Placebo | 25 | 67 | 60.0 | |||||
| Hewitt et al12 | Cholecalciferol | 30 | Patients with were randomized to receive 50,000 IU oral cholecalciferol or placebo, once weekly for 8 weeks and then monthly for 4 months. | Patients with 25(OH)D 24 ng/mL, were on thrice-weekly HD for 3 months, without hypercalcemia. | Immulite 2000 system | RIA (DiaSorin Inc) | 60* | 53.0 |
| Placebo | 30 | 67* | 43.0 | |||||
| Delanaye et al17 | Cholecalciferol | 16 | Patients were randomized to receive placebo or cholecalciferol (25,000 IU) therapy every 2 weeks. | On HD for at least 12 months, serum 25(OH)D 30 ng/mL, P 65 mg/L, and Ca 2.57 mmol/L. without hypercalcemia | Liaison DiaSorin, | Liaison DiaSorin | 75 | 75.0 |
| Placebo | 14 | 73 | 64.0 | |||||
| Seibert et al11 | Cholecalciferol | 15 | Patients were randomized to receive capsules, both red and looking alike, contained either mannitol/aerosil (placebo) or cholecalciferol 20,000 IU plus mannitol/aerosil (verum). Dosages depend on vitamin D levels. | Adults who had 25(OH)D depletion or insufficiency (serum 25(OH)D 80 nmol/l), >3 months on dialysis, without hypercalcemia or hyperphosphatemia within 4 weeks. | 1–84-intact, ECLIA | 1,25(OH)2D (Radio-Immuno-Assay, BioSource Europe), 25(OH) D (Chemiluminescence Immunoassay, DiaSorin) | 66.9 | 60.0 |
| Placebo | 18 | 67.4 | 50.0 | |||||
| Marckmann et al21 | Cholecaciferol | 13 | The treated group received one capsule containing 40,000 IU of vitaminD3 weekly for 8 weeks. The placebo group received lactose capsules that looked identical. | Adults on HD for median 32 months (range 4–158 months) with plasma 25-OHD50 nmol/L without hypercalcemia or hyperphosphatemia. | NR | NR | N/A† | 73.0 |
| Placebo | 14 | N/A† | 76.9 | |||||
| Armas et al22 | Cholecalciferol | 20 | Immediately after each dialysis session, subjects received oral cholecalciferol or placebo once per week for 15 weeks. Placebo was lactose encapsulated in an opaque capsule. | Adults on HD for more than 3 months. Vitamin D status was not a criterion for selection. | RIA using DiaSorin N-tact PTH SP IRMA kit | RIA kit (Nichols Institute, San Clemente, California, USA) | 57.6* | 70.0 |
| Placebo | 22 | 54.3* | 73.0 | |||||
| Wasse et al23 | Cholecalciferol | 25 | Vitamin D3 and placebo were identical in shape and color. The cholecalciferol group received 200,000 IU (4 pills of 50,000 IU vitamin D3) once weekly for 3 weeks. | Adults on HD (means of 259 days for study group and 839 days for placebo group) with majority (94%) having 25(OH)D 30 ng/mL, and without hypercalcemia within 4 weeks. | NA† | 1,25(OH)2D (solid-phase extraction and RIA by ARUP Laboratory), 25(OH) D (Chemiluminescence Immunoassay, DiaSorin) | 49 | 60.0 |
| Placebo | 27 | 52 | 63.0 |
*Presented by median.
†NR, information not reported.
Ca, calcium; ECLIA, electrochemiluminescence immunoassay; HD, hemodialysis; iPTH, intact parathyroid hormones; IU, international unit; NA, not applicable; NKF-KDOQI, National Kidney Foundation–Kidney Disease Outcomes Quality Initiative); P, phosphorus; RCT, random controlled trials; RIA, radioimmunoassay.