Semi-Parametric Non-Proportional Hazard Model With Time Varying Covariate

The application of survival analysis has extended the importance of statistical methods for time to event data that incorporate time dependent covariates. The Cox proportional hazards model is one such method that is widely used. An extension of the Cox model with time-dependent covariates was adopted when proportionality assumption are violated. The purpose of this study is to validate the model assumption when hazard rate varies with time. This approach is applied to model data on duration of infertility subject to time varying covariate. Validity is assessed by a set of simulation experiments and results indicate that a non proportional hazard model performs well in the phase of violated assumptions of the Cox proportional hazards

Correction to: The interrelationship between LST, NDVI, NDBI, and land cover change in a section of Lagos metropolis, Nigeria

This article was inadvertently published shortly after the initial submission of the correction. There had been a correction in Eq. 3 and Tables 8, 9, 10 when the whole team of authors finalized the corrections. The authors have limited the analysis of variation in LST, NDVI, and NDBI, and their relationship with land cover to the Landsat 8-derived data only (2013, 2016, and 2019). Consequently, the year 2002 has been excluded from the initial tables 8, 9, 10, 11. Given here are the corrected equation and table

Stroke genetics informs drug discovery and risk prediction across ancestries

Previous genome-wide association studies (GWASs) of stroke — the second leading cause of death worldwide — were conducted predominantly in populations of European ancestry1,2. Here, in cross-ancestry GWAS meta-analyses of 110,182 patients who have had a stroke (five ancestries, 33% non-European) and 1,503,898 control individuals, we identify association signals for stroke and its subtypes at 89 (61 new) independent loci: 60 in primary inverse-variance-weighted analyses and 29 in secondary meta-regression and multitrait analyses. On the basis of internal cross-ancestry validation and an independent follow-up in 89,084 additional cases of stroke (30% non-European) and 1,013,843 control individuals, 87% of the primary stroke risk loci and 60% of the secondary stroke risk loci were replicated (P < 0.05). Effect sizes were highly correlated across ancestries. Cross-ancestry fine-mapping, in silico mutagenesis analysis3, and transcriptome-wide and proteome-wide association analyses revealed putative causal genes (such as SH3PXD2A and FURIN) and variants (such as at GRK5 and NOS3). Using a three-pronged approach4, we provide genetic evidence for putative drug effects, highlighting F11, KLKB1, PROC, GP1BA, LAMC2 and VCAM1 as possible targets, with drugs already under investigation for stroke for F11 and PROC. A polygenic score integrating cross-ancestry and ancestry-specific stroke GWASs with vascular-risk factor GWASs (integrative polygenic scores) strongly predicted ischaemic stroke in populations of European, East Asian and African ancestry5. Stroke genetic risk scores were predictive of ischaemic stroke independent of clinical risk factors in 52,600 clinical-trial participants with cardiometabolic disease. Our results provide insights to inform biology, reveal potential drug targets and derive genetic risk prediction tools across ancestries

Profile and causes of mortality among elderly patients seen in a tertiary care hospital in Nigeria

Background: Old age is one of the factors associated with increased risk of dying when admitted to hospital. Therefore, aim of this study was to examine causes and pattern of death among elderly patients managed in a tertiary care hospital in Nigeria with scanty mortality records. Materials and Methods: This prospective study was on deaths that occurred in patients 60 years and above admitted to University of Ilorin Teaching Hospital (UITH), Ilorin, between January 2005 and June 2007. Excluded were all brought-in-dead during the study period. Information obtained included demographic data, duration on admission, and diagnosis. Causes of death were determined from clinical progress notes and diagnosis. Results: A total of 1298 deaths occurred during the study period, of which 297 occurred in persons 60 years and above with crude death rate of 22.8%. The mean age at death was 68 \ub1 9 years (ranged 60-100 years). This consisted of 59% males and 41% females. Mean age at death for females was 69.7 \ub1 8.7 years and for males 68.1 \ub1 9.8 years (P=0.05). Mean values of serum chemistry were sodium 137 \ub1 8 mMol/l, potassium 3.6 \ub1 1 mMol/l, urea 11 \ub1 8 mMol/l, and creatinine 126 \ub1 91 \u3bcmol/l. The value of mean haemogram concentration was 10.5 \ub1 3\u2005gm/dl and white cell count was 12 \ub1 2 7 10 9 /\u2005mm 3 . The three most common diagnoses at deaths were stroke (19.8%), sepsis (16.5%), and lower respiratory tract disease (8.1%). Infectious diseases accounted for 38.2% of all diagnoses. Collective mean length of hospital stay (LOS) at death was 6.8 \ub1 8.6 (ranged 15\u2005minutes-60 days). Close to 27.4% of the deaths occurred within 24 hours and neurological disorder had shortest hospital stay (4.6 \ub1 6.3 days), followed by endocrine disorders (6.8 \ub1 8.4 days) and respiratory diseases (8.4 \ub1 5.6 days) [P=0.001]. Conclusion: Hospital mortality is high amongst older people. Stroke and infectious diseases are leading causes of death. Efforts should be geared toward reducing risk for cardiovascular diseases and improvement on level of personal and community hygiene

Profile and causes of mortality among elderly patients seen in a tertiary care hospital in Nigeria

Background: Old age is one of the factors associated with increased risk of dying when admitted to hospital. Therefore, aim of this study was to examine causes and pattern of death among elderly patients managed in a tertiary care hospital in Nigeria with scanty mortality records. Materials and Methods: This prospective study was on deaths that occurred in patients 60 years and above admitted to University of Ilorin Teaching Hospital (UITH), Ilorin, between January 2005 and June 2007. Excluded were all brought-in-dead during the study period. Information obtained included demographic data, duration on admission, and diagnosis. Causes of death were determined from clinical progress notes and diagnosis. Results: A total of 1298 deaths occurred during the study period, of which 297 occurred in persons 60 years and above with crude death rate of 22.8%. The mean age at death was 68 ± 9 years (ranged 60-100 years). This consisted of 59% males and 41% females. Mean age at death for females was 69.7 ± 8.7 years and for males 68.1 ± 9.8 years (P=0.05). Mean values of serum chemistry were sodium 137 ± 8 mMol/l, potassium 3.6 ± 1 mMol/l, urea 11 ± 8 mMol/l, and creatinine 126 ± 91 μmol/l. The value of mean haemogram concentration was 10.5 ± 3 gm/dl and white cell count was 12 ± 2 × 10 9 / mm 3 . The three most common diagnoses at deaths were stroke (19.8%), sepsis (16.5%), and lower respiratory tract disease (8.1%). Infectious diseases accounted for 38.2% of all diagnoses. Collective mean length of hospital stay (LOS) at death was 6.8 ± 8.6 (ranged 15 minutes-60 days). Close to 27.4% of the deaths occurred within 24 hours and neurological disorder had shortest hospital stay (4.6 ± 6.3 days), followed by endocrine disorders (6.8 ± 8.4 days) and respiratory diseases (8.4 ± 5.6 days) [P=0.001]. Conclusion: Hospital mortality is high amongst older people. Stroke and infectious diseases are leading causes of death. Efforts should be geared toward reducing risk for cardiovascular diseases and improvement on level of personal and community hygiene

SARS-CoV-2 vaccination modelling for safe surgery to save lives: data from an international prospective cohort study

Background: Preoperative SARS-CoV-2 vaccination could support safer elective surgery. Vaccine numbers are limited so this study aimed to inform their prioritization by modelling. Methods: The primary outcome was the number needed to vaccinate (NNV) to prevent one COVID-19-related death in 1 year. NNVs were based on postoperative SARS-CoV-2 rates and mortality in an international cohort study (surgical patients), and community SARS-CoV-2 incidence and case fatality data (general population). NNV estimates were stratified by age (18-49, 50-69, 70 or more years) and type of surgery. Best- and worst-case scenarios were used to describe uncertainty. Results: NNVs were more favourable in surgical patients than the general population. The most favourable NNVs were in patients aged 70 years or more needing cancer surgery (351; best case 196, worst case 816) or non-cancer surgery (733; best case 407, worst case 1664). Both exceeded the NNV in the general population (1840; best case 1196, worst case 3066). NNVs for surgical patients remained favourable at a range of SARS-CoV-2 incidence rates in sensitivity analysis modelling. Globally, prioritizing preoperative vaccination of patients needing elective surgery ahead of the general population could prevent an additional 58 687 (best case 115 007, worst case 20 177) COVID-19-related deaths in 1 year. Conclusion: As global roll out of SARS-CoV-2 vaccination proceeds, patients needing elective surgery should be prioritized ahead of the general population

Effects of pre-operative isolation on postoperative pulmonary complications after elective surgery: an international prospective cohort study an international prospective cohort study

We aimed to determine the impact of pre-operative isolation on postoperative pulmonary complications after elective surgery during the global SARS-CoV-2 pandemic. We performed an international prospective cohort study including patients undergoing elective surgery in October 2020. Isolation was defined as the period before surgery during which patients did not leave their house or receive visitors from outside their household. The primary outcome was postoperative pulmonary complications, adjusted in multivariable models for measured confounders. Pre-defined sub-group analyses were performed for the primary outcome. A total of 96,454 patients from 114 countries were included and overall, 26,948 (27.9%) patients isolated before surgery. Postoperative pulmonary complications were recorded in 1947 (2.0%) patients of which 227 (11.7%) were associated with SARS-CoV-2 infection. Patients who isolated pre-operatively were older, had more respiratory comorbidities and were more commonly from areas of high SARS-CoV-2 incidence and high-income countries. Although the overall rates of postoperative pulmonary complications were similar in those that isolated and those that did not (2.1% vs 2.0%, respectively), isolation was associated with higher rates of postoperative pulmonary complications after adjustment (adjusted OR 1.20, 95%CI 1.05–1.36, p = 0.005). Sensitivity analyses revealed no further differences when patients were categorised by: pre-operative testing; use of COVID-19-free pathways; or community SARS-CoV-2 prevalence. The rate of postoperative pulmonary complications increased with periods of isolation longer than 3 days, with an OR (95%CI) at 4–7 days or ≥ 8 days of 1.25 (1.04–1.48), p = 0.015 and 1.31 (1.11–1.55), p = 0.001, respectively. Isolation before elective surgery might be associated with a small but clinically important increased risk of postoperative pulmonary complications. Longer periods of isolation showed no reduction in the risk of postoperative pulmonary complications. These findings have significant implications for global provision of elective surgical care. We aimed to determine the impact of pre-operative isolation on postoperative pulmonary complications after elective surgery during the global SARS-CoV-2 pandemic. We performed an international prospective cohort study including patients undergoing elective surgery in October 2020. Isolation was defined as the period before surgery during which patients did not leave their house or receive visitors from outside their household. The primary outcome was postoperative pulmonary complications, adjusted in multivariable models for measured confounders. Pre-defined sub-group analyses were performed for the primary outcome. A total of 96,454 patients from 114 countries were included and overall, 26,948 (27.9%) patients isolated before surgery. Postoperative pulmonary complications were recorded in 1947 (2.0%) patients of which 227 (11.7%) were associated with SARS-CoV-2 infection. Patients who isolated pre-operatively were older, had more respiratory comorbidities and were more commonly from areas of high SARS-CoV-2 incidence and high-income countries. Although the overall rates of postoperative pulmonary complications were similar in those that isolated and those that did not (2.1% vs 2.0%, respectively), isolation was associated with higher rates of postoperative pulmonary complications after adjustment (adjusted OR 1.20, 95%CI 1.05–1.36, p = 0.005). Sensitivity analyses revealed no further differences when patients were categorised by: pre-operative testing; use of COVID-19-free pathways; or community SARS-CoV-2 prevalence. The rate of postoperative pulmonary complications increased with periods of isolation longer than 3 days, with an OR (95%CI) at 4–7 days or ≥ 8 days of 1.25 (1.04–1.48), p = 0.015 and 1.31 (1.11–1.55), p = 0.001, respectively. Isolation before elective surgery might be associated with a small but clinically important increased risk of postoperative pulmonary complications. Longer periods of isolation showed no reduction in the risk of postoperative pulmonary complications. These findings have significant implications for global provision of elective surgical care