Incidence of HIV and hepatitis C virus among people who inject drugs, and associations with age and sex or gender: a global systematic review and meta-analysis

Background: Measuring the incidence of HIV and hepatitis C virus (HCV) infection among people who inject drugs (PWID) is key to track progress towards elimination. We aimed to summarise global data on HIV and primary HCV incidence among PWID and associations with age and sex or gender. Methods: In this systematic review and meta-analysis, we updated an existing database of HIV and HCV incidence studies among PWID by searching MEDLINE, Embase, and PsycINFO, capturing studies published between Jan 1, 2000, and Dec 12, 2022, with no language or study design restrictions. We contacted authors of identified studies for unpublished or updated data. We included studies that estimated incidence by longitudinally re-testing people at risk of infection or by using assays for recent infection. We pooled incidence and relative risk (RR; young [generally defined as ≤25 years] vs older PWID; women vs men) estimates using random-effects meta-analysis and assessed risk of bias with a modified Newcastle–Ottawa scale. This study is registered with PROSPERO, CRD42020220884. Findings: Our updated search identified 9493 publications, of which 211 were eligible for full-text review. An additional 377 full-text records from our existing database and five records identified through cross-referencing were assessed. Including 28 unpublished records, 125 records met the inclusion criteria. We identified 64 estimates of HIV incidence (30 from high-income countries [HICs] and 34 from low-income or middle-income countries [LMICs]) and 66 estimates of HCV incidence (52 from HICs and 14 from LMICs). 41 (64%) of 64 HIV and 42 (64%) of 66 HCV estimates were from single cities rather than being multi-city or nationwide. Estimates were measured over 1987–2021 for HIV and 1992–2021 for HCV. Pooled HIV incidence was 1·7 per 100 person-years (95% CI 1·3–2·3; I2=98·4%) and pooled HCV incidence was 12·1 per 100 person-years (10·0–14·6; I2=97·2%). Young PWID had a greater risk of HIV (RR 1·5, 95% CI 1·2–1·8; I2=66·9%) and HCV (1·5, 1·3–1·8; I2=70·6%) acquisition than older PWID. Women had a greater risk of HIV (RR 1·4, 95% CI 1·1–1·6; I2=55·3%) and HCV (1·2, 1·1–1·3; I2=43·3%) acquisition than men. For both HIV and HCV, the median risk-of-bias score was 6 (IQR 6–7), indicating moderate risk. Interpretation: Although sparse, available HIV and HCV incidence estimates offer insights into global levels of HIV and HCV transmission among PWID. Intensified efforts are needed to keep track of the HIV and HCV epidemics among PWID and to expand access to age-appropriate and gender-appropriate prevention services that serve young PWID and women who inject drugs. Funding: Canadian Institutes of Health Research, Fonds de recherche du Québec–Santé, Canadian Network on Hepatitis C, UK National Institute for Health and Care Research, and WHO

Simultaneous versus sequential one-stage combined anterior and posterior spinal surgery for spinal infections (outcomes and complications)

To compare simultaneous with sequential one-stage (same anaesthesia) combined anterior and posterior spinal surgery in the treatment of spinal infections in terms of the operation time, blood loss and complication rate. Fifty-six patients who underwent one-stage (same anaesthesia) simultaneous or sequential anterior decompression and posterior stabilisation of the involved vertebrae for spinal infection from January 1994 to December 2002 were reviewed. In group I (n=29), sequential anterior and posterior surgery was performed. In group II (n=27), simultaneous anterior and posterior spinal surgery was performed. With regard to age and gender, there was no statistical difference between both groups (P=0.05). The analysed and compared data between the two groups included the age, gender, blood loss, operation time and postoperative complications. There was a statistically significant difference between the two groups in terms of the duration of surgery, amount of blood transfusion needed and occurrence of major postoperative complications (P<0.05). The mean correction of the kyphotic deformity was similar in both groups (P>0.05) without a subsequent loss of correction on follow-up radiographic films at a mean follow-up of 6.5 years (range, 3 to 11 years). Simultaneous anterior and posterior surgery is a good alternative procedure. It provides the ability to manipulate both anterior and posterior aspects of the spine at the same time and appears to result in less blood loss, a shorter operative time and fewer complications. However, gaining experience and the availability of two surgical teams are important factors in the success of the procedure

A new approach to the treatment of separatrix chaos and its applications

"Hamiltonian Chaos Beyond the KAM Theory: Dedicated to George M. Zaslavsky (1935 - 2008)" covers the recent developments and advances in the theory and application of Hamiltonian chaos in nonlinear Hamiltonian systems. The book is dedicated to Dr. George Zaslavsky, who was one of three founders of the theory of Hamiltonian chaos. Each chapter in this book was written by well-established scientists in the field of nonlinear Hamiltonian systems. The development presented in this book goes beyond the KAM theory, and the onset and disappearance of chaos in the stochastic and resonant layers of nonlinear Hamiltonian systems are predicted analytically, instead of qualitatively. The book is intended for researchers in the field of nonlinear dynamics in mathematics, physics and engineering. Dr. Albert C.J. Luo is a Professor at Southern Illinois University Edwardsville, USA. Dr. Valentin Afraimovich is a Professor at San Luis Potosi University, Mexico