World Bank Regions Research Articles

Global Prevalence of Hypertension in Children

Reliable estimates of the prevalence of childhood hypertension serve as the basis for adequate prevention and treatment. However, the prevalence of childhood hypertension has rarely been synthesized at the global level. To conduct a systematic review and meta-analysis to assess the prevalence of hypertension in the general pediatric population. PubMed, MEDLINE, Embase, Global Health, and Global Health Library were searched from inception until June 2018, using search terms related to hypertension (hypertension OR high blood pressure OR elevated blood pressure), children (children OR adolescents), and prevalence (prevalence OR epidemiology). Studies that were conducted in the general pediatric population and quantified the prevalence of childhood hypertension were eligible. Included studies had blood pressure measurements from at least 3 separate occasions. Two authors independently extracted data. Random-effects meta-analysis was used to derive the pooled prevalence. Variations in the prevalence estimates in different subgroups, including age group, sex, setting, device, investigation period, BMI group, World Health Organization region and World Bank region, were examined by subgroup meta-analysis. Meta-regression was used to establish the age-specific prevalence of childhood hypertension and to assess its secular trend. Prevalence of childhood hypertension overall and by subgroup. A total of 47 articles were included in the meta-analysis. The pooled prevalence was 4.00% (95% CI, 3.29%-4.78%) for hypertension, 9.67% (95% CI, 7.26%-12.38%) for prehypertension, 4.00% (95% CI, 2.10%-6.48%) for stage 1 hypertension, and 0.95% (95% CI, 0.48%-1.57%) for stage 2 hypertension in children 19 years and younger. In subgroup meta-analyses, the prevalence of childhood hypertension was higher when measured by aneroid sphygmomanometer (7.23% vs 4.59% by mercury sphygmomanometer vs 2.94% by oscillometric sphygmomanometer) and among overweight and obese children (15.27% and 4.99% vs 1.90% among normal-weight children). A trend of increasing prevalence of childhood hypertension was observed during the past 2 decades, with a relative increasing rate of 75% to 79% from 2000 to 2015. In 2015, the prevalence of hypertension ranged from 4.32% (95% CI, 2.79%-6.63%) among children aged 6 years to 3.28% (95% CI, 2.25%-4.77%) among those aged 19 years and peaked at 7.89% (95% CI, 5.75%-10.75%) among those aged 14 years. This study provides a global estimation of childhood hypertension prevalence based on blood pressure measurements in at least 3 separate visits. More high-quality epidemiologic investigations on childhood hypertension are still needed.

Magnitude and Determinants of the Ratio between Prevalence of Low Vision and Blindness in Rapid Assessment of Avoidable Blindness Surveys

ABSTRACTPurpose: To determine the magnitude and determinants of the ratio between prevalence of low vision and prevalence of blindness in rapid assessment of avoidable blindness (RAAB) surveys globally.Methods: Standard RAAB reports were downloaded from the repository or requested from principal investigators. Potential predictor variables included prevalence of uncorrected refractive error (URE) as well as gross domestic product (GDP) per capita, health expenditure per capita of the country across World Bank regions. Univariate and multivariate linear regression were used to investigate the correlation between potential predictor variables and the ratio.Results: The results of 94 surveys from 43 countries showed that the ratio ranged from 1.35 in Mozambique to 11.03 in India with a median value of 3.90 (Interquartile range 3.06;5.38). Univariate regression analysis showed that prevalence of URE (p = 0.04), logarithm of GDP per capita (p = 0.01) and logarithm of health expenditure per capita (p = 0.03) were significantly associated with the higher ratio. However, only prevalence of URE was found to be significant in multivariate regression analysis (p = 0.03).Conclusion: There is a wide variation in the ratio of the prevalence of low vision to the prevalence of blindness. Eye care service utilization indicators such as the prevalence of URE may explain some of the variation across the regions.

Impact of academic collaboration and quality of clinical orthopaedic research conducted in low- and middle-income countries.

Background: Little is known about the quality of orthopaedic investigations conducted in low- and middle-income countries (LMICs). Academic collaboration is one model to build research capacity and improve research quality. Our study aimed to determine (1) the quality of clinical orthopaedic research conducted in LMICs, (2) the World Bank Regions and LMICs that publish the highest quality studies, (3) the pattern of collaboration among investigators and (4) whether academic collaboration between LMIC and non-LMIC investigators is associated with studies that have higher levels of evidence. Methods: Orthopaedic studies from 2004 to 2014 conducted in LMICs were extracted from multiple electronic databases. The World Bank Region, level of evidence and author country-affiliation were recorded. Collaboration was defined as a study that included an LMIC with non-LMIC investigator. Results: There were 958 studies that met inclusion criteria of 22,714 searched. Ninety-seven (10.1%) of included studies achieved Level 1 or 2 evidence, but case series (52.3%) were the most common. Collaboration occurred in 14.4% of studies and the vast majority of these (88.4%) were among academic institutions. Collaborative studies were more likely to be Level 1 or 2 (20.3% vs. 8.4%, p < 0.01), prospective (34.8% vs. 22.9% p = 0.04) and controlled (29.7% vs. 14.4%, p < 0.01) compared to non-collaborative studies. Conclusions: Although orthopaedic studies in LMICs rarely reach Level 1 or 2 evidence, studies published through academic collaboration between LMIC and non-LMIC investigators are associated with higher levels of evidence and more prospective, controlled designs.

Abstract TP222: Frequency of Intracranial Arterial Imaging and its Yield in Consecutive Patients with Non-lacunar Cryptogenic Ischemic Stroke: ESUS Global Registry

Background: Atherosclerotic stenosis of large IC arteries is an important cause of stroke. The prevalence of ICS in stroke population differs by ethnicity.We report the frequency of ICS among a global sample of patients with non-lacunar cryptogenic ischemic stroke (NLCIS) who did not have another identifiable cause for stroke i.e. cardioembolic, extracranial LAD, or other specific causes. Hypothesis: We hypothesized that the prevalence rates of ICS will differ according to global regions. Methods: Consecutive patients with recent ischemic stroke were retrospectively surveyed at 19 stroke centers in 19 countries to identify the frequency of IC imaging and its yield. Countries were grouped by World Bank regions. ICS was considered to be significant if there was &gt;50% stenosis in the arteries proximal to the index stroke evidenced by MRA, CTA or TCD. Results: We identified a total of 2145 consecutive ischemic stroke patients among which 475 had NLCIS. IC arterial imaging was carried-out,on average, in 87% of patients. Of these 414 patients, 15% had stenosis proximal to the area of brain ischemia. The frequency of ICS among NLCIS patients was highest in East Asia (27%) and lowest in Pacific (4%). Patients with ICS in Latin America were significantly younger when compared to other 4 regions. Conclusion: IC arterial imaging is carried out in majority of stroke centers in patients with NLCIS, among whom the fraction of IS associated with ICS is substantial throughout the world, averaging about 15%. MRA / CTA had a higher yield than TCD. On average these patients have traditional vascular risk factors except for Latin American patients who are significantly younger with no vascular risk factors.

Prevalence of Hypertension in Low- and Middle-Income Countries: A Systematic Review and Meta-Analysis.

We aimed to obtain overall and regional estimates of hypertension prevalence, and to examine the pattern of this disease condition across different socio-demographic characteristics in low-and middle-income countries. We searched electronic databases from inception to August 2015. We included population-based studies that reported hypertension prevalence using the current definition of blood pressure ≥140/90 mm Hg or self-reported use of antihypertensive medication. We used random-effects meta-analyses to pool prevalence estimates of hypertension, overall, by World Bank region and country income group. Meta-regression analyses were performed to explore sources of heterogeneity across the included studies. A total of 242 studies, comprising data on 1,494,609 adults from 45 countries, met our inclusion criteria. The overall prevalence of hypertension was 32.3% (95% confidence interval [CI] 29.4-35.3), with the Latin America and Caribbean region reporting the highest estimates (39.1%, 95% CI 33.1-45.2). Pooled prevalence estimate was also highest across upper middle income countries (37.8%, 95% CI 35.0-40.6) and lowest across low-income countries (23.1%, 95% CI 20.1-26.2). Prevalence estimates were significantly higher in the elderly (≥65 years) compared with younger adults (<65 years) overall and across the geographical regions; however, there was no significant sex-difference in hypertension prevalence (31.9% vs 30.8%, P = 0.6). Persons without formal education (49.0% vs 24.9%, P < 0.00001), overweight/obese (46.4% vs 26.3%, P < 0.00001), and urban settlers (32.7% vs 25.2%, P = 0.0005) were also more likely to be hypertensive, compared with those who were educated, normal weight, and rural settlers respectively. This study provides contemporary and up-to-date estimates that reflect the significant burden of hypertension in low- and middle-income countries, as well as evidence that hypertension remains a major public health issue across the various socio-demographic subgroups. On average, about 1 in 3 adults in the developing world is hypertensive. The findings of this study will be useful for the design of hypertension screening and treatment programmes in low- and middle-income countries.

The Gap between Estimated Incidence of End-Stage Renal Disease and Use of Therapy

BackgroundRelatively few data exist on the burden of end-stage renal disease (ESRD) and use of renal replacement therapy (RRT)–a life-saving therapy–in developing regions. No study has quantified the proportion of patients who develop ESRD but are unable to access RRT.MethodsWe performed a comprehensive literature search to estimate use and annual initiation of RRT worldwide, and present these estimates according to World Bank regions. We also present estimates of survival and of etiology of diseases in patients undergoing RRT. Using data on prevalence of diabetes and hypertension, we modeled the incidence of ESRD related to these risk factors in order to quantify the gap between ESRD and use of RRT in developing regions.ResultsWe find that 1.9 million patients are undergoing RRT worldwide, with continued use and annual initiation at 316 and 73 per million population respectively. RRT use correlates directly (Pearson’s r = 0.94) with regional income. Hemodialysis remains the dominant form of RRT but there is wide regional variation in its use. With the exception of the Latin American and Caribbean region, it appears that initiation of RRT in developing regions is restricted to fewer than a quarter of patients projected to develop ESRD. This results in at least 1.2 million premature deaths each year due to lack of access to RRT as a result of diabetes and elevated blood pressure and as many as 3.2 million premature deaths due to all causes of ESRD.ConclusionThus, the majority of patients projected to reach ESRD due to diabetes or hypertension in developing regions are unable to access RRT; this gap will increase with rising prevalence of these risk factors worldwide.

A population-based study of tuberculosis epidemiology and innovative service delivery in Canada

To compare and interpret tuberculosis (TB) incidence rates in a Canadian population across two decennials (1989-1998 and 1999-2008) as a benchmark for World Health Organization targets and the long-term goal of TB elimination. The population under study was served by two urban clinics in the first decennial and two urban and one provincial clinic in the second. TB rates among Status Indians, Canadian-born 'others' and the foreign-born were estimated using provincial and national databases. Program performance was measured in on-reserve Status Indians in each decennial. In each decennial, the incidence rate in Status Indians and the foreign-born was greater than that in the Canadian-born 'others'; respectively 27.7 and 33.0 times in Status Indians, and 8.0 and 20.9 times in the foreign-born. Between decennials, the rate fell by 56% in Status Indians, 58% in Canadian-born 'others', and 18% in the foreign-born. On-reserve Status Indians had higher rates than off-reserve Status Indians, and the three-clinic model out-performed the two-clinic model among those on-reserve. Rates in the foreign-born varied by World Bank region, and were highest among those from Africa and Asia. Status Indians and the foreign-born are at increased risk of TB in Canada. Significant progress towards TB elimination has been made in Status Indians but not in the foreign-born.

The global cost of nonoptimal blood pressure

Suboptimal blood pressure including established nonoptimal blood pressure has been shown to have significant economic consequences in developed countries. However, no exhaustive study has been done to evaluate its potential costs, globally. We, therefore, set out to estimate the global economic cost of nonoptimal blood pressure. Estimates for healthcare costs attributed to suboptimal blood pressure for those over the age of 30 were made for all the World Bank regions. Annual and 10-year estimates using Markov models were made for the cost of treating nonoptimal blood pressure and its main sequelae: stroke and myocardial infarction. Suboptimal blood pressure cost US$370,000,000,000 globally in 2001. This represents about 10% of the world's overall healthcare expenditures. In the Eastern Europe and Central Asia region, high blood pressure consumed 25% of all health expenditures. Over a 10-year period, elevated blood pressure may cost nearly $1,000,000,000,000 globally in health spending, if current blood pressure levels persist. Indirect costs could be as high as $3,600,000,000,000 annually. Suboptimal blood pressure is responsible for a large and an increasing economic and health burden in developing countries. Although the majority of the current absolute expenditure occurs in the high-income countries, an ever-increasing proportion of the cost is going to be carried by developing countries.

Global burden of blood-pressure-related disease, 2001

Few studies have assessed the extent and distribution of the blood-pressure burden worldwide. The aim of this study was to quantify the global burden of disease related to high blood pressure. Worldwide burden of disease attributable to high blood pressure (> or =115 mm Hg systolic) was estimated for groups according to age (> or =30 years), sex, and World Bank region in the year 2001. Population impact fractions were calculated with data for mean systolic blood pressure, burden of deaths and disability-adjusted life years (DALYs), and relative risk corrected for regression dilution bias. Worldwide, 7.6 million premature deaths (about 13.5% of the global total) and 92 million DALYs (6.0% of the global total) were attributed to high blood pressure. About 54% of stroke and 47% of ischaemic heart disease worldwide were attributable to high blood pressure. About half this burden was in people with hypertension; the remainder was in those with lesser degrees of high blood pressure. Overall, about 80% of the attributable burden occurred in low-income and middle-income economies, and over half occurred in people aged 45-69 years. Most of the disease burden caused by high blood pressure is borne by low-income and middle-income countries, by people in middle age, and by people with prehypertension. Prevention and treatment strategies restricted to individuals with hypertension will miss much blood-pressure-related disease.

Cardiovascular disease prevention with a multidrug regimen in the developing world: a cost-effectiveness analysis

Cardiovascular disease is the leading cause of death, with 80% of cases occurring in developing countries. We therefore aimed to establish whether use of evidence-based multidrug regimens for patients at high risk for cardiovascular disease would be cost-effective in low-income and middle-income countries. We used a Markov model to do a cost-effectiveness analysis with two combination regimens. For primary prevention, we used aspirin, a calcium-channel blocker, an angiotensin-converting-enzyme inhibitor, and a statin, and assessed them in four groups with different thresholds of absolute risks for cardiovascular disease. For secondary prevention, we assessed the same combination of drugs in one group, but substituted a beta blocker for the calcium-channel blocker. To compare strategies, we report incremental cost-effectiveness ratios (ICER), in US dollars per quality-adjusted life-year (QALY). We recorded that preventive strategies could result in a 2-year gain in life expectancy. Across six developing World Bank regions, primary prevention yielded ICERs of US746-890 dollars/QALY gained for patients with a 10-year absolute risk of cardiovascular disease greater than 25%, and 1039-1221 dollars/QALY gained for those with an absolute risk greater than 5%. ICERs for secondary prevention ranged from 306 dollars/QALY to 388 dollars/QALY gained. Regimens of aspirin, two blood-pressure drugs, and a statin could halve the risk of death from cardiovascular disease in high-risk patients. This approach is cost-effective according to WHO recommendations, and is robust across several estimates of drug efficacy and of treatment cost. Developing countries should encourage the use of these inexpensive drugs that are currently available for both primary and secondary prevention.

Causes of cancer in the world: comparative risk assessment of nine behavioural and environmental risk factors

With respect to reducing mortality, advances in cancer treatment have not been as effective as those for other chronic diseases; effective screening methods are available for only a few cancers. Primary prevention through lifestyle and environmental interventions remains the main way to reduce the burden of cancers. In this report, we estimate mortality from 12 types of cancer attributable to nine risk factors in seven World Bank regions for 2001. We analysed data from the Comparative Risk Assessment project and from new sources to assess exposure to risk factors and relative risk by age, sex, and region. We applied population attributable fractions for individual and multiple risk factors to site-specific cancer mortality from WHO. Of the 7 million deaths from cancer worldwide in 2001, an estimated 2.43 million (35%) were attributable to nine potentially modifiable risk factors. Of these, 0.76 million deaths were in high-income countries and 1.67 million in low-and-middle-income nations. Among low-and-middle-income regions, Europe and Central Asia had the highest proportion (39%) of deaths from cancer attributable to the risk factors studied. 1.6 million of the deaths attributable to these risk factors were in men and 0.83 million in women. Smoking, alcohol use, and low fruit and vegetable intake were the leading risk factors for death from cancer worldwide and in low-and-middle-income countries. In high-income countries, smoking, alcohol use, and overweight and obesity were the most important causes of cancer. Sexual transmission of human papilloma virus is a leading risk factor for cervical cancer in women in low-and-middle-income countries. Reduction of exposure to key behavioural and environmental risk factors would prevent a substantial proportion of deaths from cancer.

Welfare Policy and Social Transfers in Croatia

This Occasional Paper occurred as the byproduct of preparations for writing the report by Predrag Bejaković and Alastair McAuley “Welfare Policy and Social Transfers in the Republic of Croatia”, The World Bank, Europe and Central Asia Region, Poverty Reduction and Economic Management Unit, June 1998. The authors, Predrag Bejaković (Institute of Public Finance, Zagreb, Croatia) and Alastair McAuley (University of Essex, Colchester, England) first published the text in Croatian in the Institute's journal "Financijska praksa", Volume 23, Number 1, (March 1999). This Occasional Paper is the English language translation of the article published in "Financijska praksa".

Public Investments in Croatia

This Occasional Paper occurred as the byproduct of preparations for writing the report by Geoff Dixon, Katarina Ott and Jean-Jacques Dethier “Capital Expenditure by the Government in Croatia: Fiscal Accounts, Budgetary Institutions and Budgeting Process”, The World Bank, Europe and Central Asia Region, Poverty Reduction and Economic Management Unit, June 1998. The authors, Katarina Ott and Anto Bajo (Institute of Public Finance) first published the text in Croatian in the Institute’s journal “Financijska praksa” Volume 23, Number 1, (March 1999). This Occasional Paper is the English language translation of the article published in “Financijska praksa”.