MATERIALS AND METHODS: Ten blood collection agencies (BCAs) provided 12 months' data on donors who met eligibility criteria or were deferred, as well as details of their donation practices. Body mass index and blood volumes were calculated and analysed.
RESULTS: Data on 9,599,613 donations and 154,834 deferrals from six national and four regional BCAs revealed varied donation eligibility and collection practices. Seven used haemoglobin (Hb) criteria below the World Health Organization anaemia threshold. Seven accepted donors weighing <50 kg. Data collection on the weight and height of donors and on deferrals was inconsistent, often not routine. Deferred donors appear to weigh less, with corresponding lower estimated blood volume.
CONCLUSION: The diversity in eligibility criteria and donation practices reflects each BCA's strategy for balancing donor health with securing an adequate blood supply. Use of lower Hb criteria substantiate their appropriateness in Asia and indicate the need to define Hb reference intervals relevant to each population. We encourage routine gathering of donor weight and height data to enable blood volume estimation and local optimization of donation volumes. Blood volume estimation formulae specific for the Asian phenotype is needed. Information from this study would be useful for tailoring donation criteria of Asian donors around the world.
METHODS: This retrospective study was performed on all KTRs ≥18 years of age at our center from January 1, 2006 to December 31, 2015, who were prescribed diltiazem as tacrolimus-sparing agent. Blood tacrolimus trough level (TacC0) and other relevant clinical data for 70 eligible KTRs were reviewed.
RESULTS: The dose of 1 mg tacrolimus resulted in a median TacC0 of 0.83 ± 0.52 ng/mL. With the introduction of a 90-mg/d dose diltiazem, there was a significant TacC0 increase to 1.39 ± 1.31 ng/mL/mg tacrolimus (P < .01). A further 90-mg increase in diltiazem to 180 mg/d resulted in a further increase of TacC0 to 1.66 ± 2.58 ng/mL/mg tacrolimus (P = .01). After this, despite a progressive increment of every 90-mg/d dose diltiazem to 270 mg/d and 360 mg/d, there was no further increment in TacC0 (1.44 ± 1.15 ng/mL/mg tacrolimus and 1.24 ± 0.94 ng/mL/mg tacrolimus, respectively [P < .01]). Addition of 180 mg/d diltiazem reduced the required tacrolimus dose to 4 mg/d, resulting in a cost-savings of USD 2045.92 per year (per patient) at our center. Adverse effects reported within 3 months of diltiazem introduction were bradycardia (1.4%) and postural hypotension (1.4%), which resolved after diltiazem dose reduction.
CONCLUSION: Coadministration of tacrolimus and diltiazem in KTRs appeared to be safe and resulted in a TacC0 increment until reaching a 180-mg/d total diltiazem dose, at which point it began to decrease. This approach will result in a marked savings in immunosuppression costs among KTRs in Malaysia.