Prevention of hepatitis B mother-to-child transmission in Namibia: A cost-effectiveness analysis.

Despite access to a safe and effective vaccine, mother-to-child transmission (MTCT) of hepatitis B virus (HBV) persists in Africa. This is of concern since perinatally-infected infants are at highest risk of developing hepatocellular carcinoma, a life-threatening consequence of chronic HBV infection. While tools to prevent HBV MTCT are available, the cost implications of these interventions need consideration prior to implementation. A Markov model was developed to determine the costs and health outcomes of (1) universal HBV birth dose (BD) vaccination, (2) universal BD vaccination and targeted hepatitis B immunoglobulin (HBIG), (3) maternal antiviral prophylaxis using sequential HBV viral load testing added to HBV BD vaccination and HBIG, and (4) maternal antiviral prophylaxis using sequential HBeAg testing combined with HBV BD vaccination and HBIG. Health outcomes were assessed as the number of paediatric infections averted and disability-adjusted life years (DALYs) averted. Primary cost data included consumables, human resources, and hospital facilities. HBV epidemiology, transitions probabilities, disability weights, and the risks of HBV MTCT were extracted from the literature. Incremental cost-effectiveness ratios (ICERs) were calculated to compare successive more expensive interventions to the previous less expensive one. One-way sensitivity analyses were conducted to test the robustness of the model's outputs. At the Namibian cost/DALY averted threshold of US$3 142, the (1) BD vaccination + targeted HBIG, and (2) maternal antiviral prophylaxis with sequential HBeAg testing interventions were cost-effective. These interventions had ICERs equal to US$1909.03/DALY and US$2598.90/DALY averted, respectively. In terms of effectiveness, the maternal antiviral prophylaxis with sequential HBeAg testing intervention was the intervention of choice. The analysis showed that elimination of HBV MTCT is achievable using maternal antiviral prophylaxis with active and passive immunization. There is an urgent need for low cost diagnostic tests to identify those women who will most benefit from drug therapy to attain this laudable goal.

Monitoring of gentamicin serum concentrations in obstetrics and gynaecology patients in Namibia.

Background Therapeutic drug monitoring is frequently used to optimize the gentamicin dose. Objective The study investigated whether a 240 mg once daily standard dose achieves the recommended target serum gentamicin concentrations. Setting The prospective, observational study took place in the 2 major public hospitals in Namibia. Method Twenty-nine female patients receiving a standard dose (240 mg gentamicin once daily) participated in the study. Two blood samples were withdrawn to estimate gentamicin pharmacokinetic parameters. Serum creatinine was used to calculate creatinine clearance with the Cockcroft-Gault formula (CLcr), and estimate glomerular filtration rate (eGFR) by the Modified Diet in Renal Disease (MDRD) and Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equations. Main outcome measure The outcome measure was the proportion of patients receiving 240 mg gentamicin once daily having Cmax values above 15 mg/L. Results Total body weight (TBW) and body mass index were highly variable: 43-115 kg, and 17.3-41.3 kg/m2, respectively. The gentamicin dose normalized for TBW (adjusted body weight for obese patients) was relatively low, i.e. 4.2 ± 0.8 mg/kg (mean SD). Gentamicin Cmax was 14.4 ± 4.7 mg/L; only 9 patients (31%) had a Cmax > 15 g/mL. eGFR (MDRD-4) correlated well with CLcr, but eGFR (EPI-CKD) formula showed systematic deviations from CLcr. Conclusions (1) a standard 240 mg dose results in gentamicin Cmax values below 15 mg/L in the majority of the patients, (2) eGFR formulas to estimate kidney function will have to be evaluated for their usefulness in the Namibian patient population.

Introducing a Mobile-Connected Umbilical Doppler Device (UmbiFlow™) into a Primary Care Maternity Setting: Does This Reduce Unnecessary Referrals to Specialised Care? Results of a Pilot Study in Kraaifontein, South Africa.

OBJECTIVES: UmbiFlow™ is a mobile-connected Doppler device that utilises a continuous waveform to measure resistance in the umbilical artery. The main aim of this pilot study was to determine whether the use of UmbiFlow™ for umbilical artery Doppler in patients with a suspected decreased symphysis fundal (SF) growth could safely lead to a decreased number of patients requiring referral to a more specialised level of care. A secondary aim of the study was to evaluate the effectiveness of UmbiFlow™ Doppler as a screening tool for concealed placental insufficiency in late bookers by using a single screening cut-off value that will be abnormal for any gestation >28 weeks. METHODS: The cohort comprised two groups of patients: The first group included all follow-up patients with suspected intra-uterine growth restriction (a decreased symphysis-fundus measurement based on serial assessment) who underwent on-site UmbiFlow™Doppler testing performed by the midwife directly after the clinical examination. The second group included late bookers, where gestation was uncertain; but estimated >28 weeks based on clinical grounds. This group was comprised of unselected patients who report to antenatal care late for the first time and received an UmbiFlow™Doppler test for concealed placental insufficiency. RESULTS: UmbiFlow™Doppler could reduce the number of false referrals to hospital by 55%. A single UmbiFlow™Doppler test in late bookers appeared to identify a group of women at moderate risk of lower birth weight babies.