iron supplements.36 Not surprisingly, the high cost of medication is a major barrier to patients with ESKD. Among HD patients, those with lower incomes tend to exhibit lower adherence to medication regimens,37 presumably due to the associated expense. Studies have shown that lower co-payments (i.e., lower out-of-pocket expenses for patients) are associated with better medication adherence among patients with chronic conditions such as diabetes and heart failure.38 Despite therapies such as PD, HD, and kidney transplantation, many people in the world suffer from untreated ESKD. It has been estimated that over 2 million people die each year due to limited access to KRT, most of whom live in low and lower-middle income countries.7 Dialysis is expensive in low and lower-middle income countries, and can cost nearly USD 1,500 per patient each year.39 Even in countries where KRT is accessible, the quality of care may vary considerably, both within and between countries. Variation in dialysis practices may contribute to differences in KRT outcomes observed worldwide.16 International guidelines may help narrow the gaps in care delivery, where possible. Additionally, government support and prioritization may improve both access to and quality of dialysis. However, it is important to consider other interventions that may be more 1.4 Access to and quality of ESKD care worldwide Over 2 million people die each year due to limited access to KRT. 24 | Introduction ISN Global Kidney Health Atlas | 2019 Acute kidney injury (AKI) is a sudden reduction in kidney function (usually within a timeframe ranging from hours to days) and manifests clinically as a reversible acute increase of nitrogen waste products (serum urea and creatinine levels). In the past, AKI was referred to as acute renal failure (ARF).42,43 AKI is a common condition associated with hospitalization and is especially common among critically ill patients, up to 40% of patients at ICU admission and 60% of patients during hospitalization. Common causes of AKI include fluid losses, infections, drugs, or toxins.44,45 In developing countries, diarrheal illnesses and nephrotoxins (usually herbal medications) contribute significantly to the development of AKI.43,44,46 AKI and CKD are closely related; CKD is a known risk factor for AKI and vice versa. Both AKI and CKD increase the risk for cardiovascular disease,47- 49 among other adverse outcomes. Appropriate, timely treatment of AKI is critical, as it can reverse kidney damage; untreated, AKI can lead to CKD progression and ultimately, ESKD. cost-effective and pragmatic in settings where the costs of dialysis are a substantial burden.39 For example, conservative care may be more appropriate in such settings, allowing patients to receive the best possible care when dialysis is not achievable. Kidney transplantation often is the preferred type of KRT. However, gaps exist with respect to both organ availability and system-level resources required for the operation. Transplantation is highly resource-intensive, and shortages in deceased donor organs further limit access.40 Limitations associated with infrastructure, the workforce, and legal frameworks as well as religious, cultural, and social constraints may contribute to low transplantation rates in some countries, among other factors.41 Due to the success of kidney transplantation and limited organ supply, vulnerable people are at risk of organ trafficking and transplant tourism. Policies to protect donor and recipient safety, enforce standards, and prohibit unethical practices are needed. 1.5 AKI Health information systems are used to collect and manage health-related data. According to the World Health Organization (WHO), a health information system is critical for decision-making; its main functions include data generation and compilation, analysis and synthesis, and communication and use.50 Well-designed health information systems are imperative for health care. Proper information management helps ensure patient safety and quality of care by reducing mistakes, improving clinical decision-making, and enabling access to information in real time.51 In addition to health information systems that collect and store individual patient health information (e.g., electronic medical records), databases or registries of population health information are important tools for achieving quality health care. Patient registries can provide hospital administrators with information on current and future resource demands. Registries also help researchers learn more about health conditions, 1.6 Health information systems Despite their importance, renal registries are lacking, particularly in lower income countries. ISN Global Kidney Health Atlas | 2019 Introduction | 25 Appropriate leadership and governance are essential healthcare system components50 that facilitate priority setting, strategy development, and policymaking activities.56 A policy is a specific official decision or set of decisions designed to carry out a course of action endorsed by a government body. In addition to priorities, goals, and general guidelines for their attainment, a policy document may include a detailed implementation strategy.57 A health policy includes decisions, plans, and actions intended to achieve a specific health care goal.58 Health policies create standardized approaches to promote equitable delivery of high-