The role of appropriate diagnostic testing in acute respiratory tract infections: An antibiotic stewardship strategy to minimise diagnostic uncertainty in primary care.

Antibiotic resistance has increased worldwide to the extent that it is now regarded as a global public health crisis. Interventions to reduce excessive antibiotic prescribing to patients can reduce resistance and improve microbiological and clinical outcomes. Therefore, although improving outpatient antibiotic use is crucial, few data are provided on the key interventional components and the effectiveness of antibiotic stewardship in the primary care setting, in South Africa. The reasons driving the excessive prescription of antibiotics in the community are multifactorial but, perhaps most importantly, the overlapping clinical features of viral and bacterial infections dramatically reduce the ability of GPs to distinguish which patients would benefit from an antibiotic or not. As a consequence, the need for tools to reduce diagnostic uncertainty is critical. In this regard, besides clinical algorithms, a consensus of collaborators in European and UK consortia recently provided guidance for the use of C-reactive protein point-of-care testing in outpatients presenting with acute respiratory tract infections (ARTIs) and/or acute cough, if it is not clear after proper clinical assessment whether antibiotics should be prescribed or not. A targeted application of stewardship principles, including diagnostic stewardship as described in this review, to the ambulatory setting has the potential to affect the most common indications for systemic antibiotic use, in that the majority (80%) of antibiotic use occurs in the community, with ARTIs the most common indication.

Cost utility of lateral-flow urine lipoarabinomannan for tuberculosis diagnosis in HIV-infected African adults.

SETTING: In-patient hospitals in South Africa and Uganda. OBJECTIVE: To evaluate the cost-effectiveness of a lateral-flow urine lipoarabinomannan (LAM) test when added to existing strategies for tuberculosis (TB) diagnosis in human immunodeficiency virus infected adults (CD4(+) T-cell counts < 100 cells/l) with symptoms of active TB. DESIGN: Decision-analytic cost-utility model, with the primary outcome being the incremental cost-effectiveness ratio, expressed in 2010 US dollars per disability-adjusted life year (DALY) averted from the perspective of a public sector TB control program. RESULTS AND CONCLUSION: For every 1000 patients tested, adding lateral-flow urine LAM generated 80 incremental appropriate anti-tuberculosis treatments and averted 224 DALYs. Estimated cost utility was US$353 per DALY averted (95% uncertainty range $192$1161) in South Africa and $86 per DALY averted (95% uncertainty range $49$239) in Uganda, reflecting the lower treatment costs in Uganda. Cost utility was most sensitive to assay specificity, cost of anti-tuberculosis treatment, life expectancy after TB cure and cohort TB prevalence, but did not rise above $1500 per DALY averted in South Africa under any one-way sensitivity analysis. The probability of acceptability was >99.8% at a per-DALY willingness-to-pay threshold equal to the per capita gross domestic product in South Africa ($7275) and Uganda ($509).