# Advances in Chronic Kidney Disease in Africa
## 5 Hypertension and CKD  
In 2019, high systolic BP was the leading risk factor for DALYs worldwide, accounting for 9.3% of all DALYs [35]. In Africa, the proportion of people affected by hypertension is estimated to be between 15 and 70% [36], and the estimated direct costs of hypertension from a South African study amount to USD 0.711 billion, with societal costs of USD 2.08 billion [37]. However, an Ethiopian study reported that treating hypertension according to the International Society of Hypertension 2020 guidelines could result in USD 9574 million in savings [38]. The cost saving is due to the decrease in hypertensive mediated organ damage, including CKD. This highlights the need for ensuring optimal blood pressure control in SSA. The CREOLE trial, performed in SSA, demonstrated excellent blood pressure control from initiating antihypertensives with the combination of a calcium channel blocker in combination with a thiazide diuretic or ACE inhibitor and is the preferred choice of initial treatment of Africans [38,39]. However, access to optimal therapies is lacking, particularly the shortage of single pill combinations. A systematic review of community-based data shows that the prevalence of CKD in SSA ranges from 2-14% and, in patients with hypertension from Africa, CKD was present in 13-51%. Vascular disease/hypertension was the most common (16%) cause of CKD, followed by diabetes, glomerulonephritis, and other causes [4]. The presence of severe hypertension was associated with a higher risk of complications. Data from a community-based study (including both rural and urban sites) from the Cote d'Ivoire found that severe hypertension was present in 14.1% of screened subjects and was almost double in urbanised regions [40]. In the setting of non-diabetic-CKD, hypertensive retinopathy was detected in 70.1% of patients from a Tanzanian tertiary centre, with grade III at 19.6% and grade IV at 13.8%, suggesting that severe/malignant hypertension is present in \(\pm\)33% of people with stages 3-5 CKD [41]. Whether severe hypertension or malignant hypertension is the cause or a result of CKD remains to be determined, but it is of concern that this is a common feature detected in the region. Modifiable risk factors for CKD are a rising concern in Africa. The Global Burden of Disease report from 2019 demonstrates the rising CV and CKD risk factors, particularly high body mass index, high systolic blood pressure, and elevated plasma glucose [34]. A community-based screening study in Nigeria identified 32.3% of subjects with prehypertension and 43.4% with hypertension. The identified modifiable risk factors included diabetes, cigarette smoking, and the use of non-steroidal anti-inflammatory and herbal substances [42]. Similarly, in other community-based studies, hypertension was found to be the most common risk factor for CKD, with 21.8% in Ethiopia and 55.4% in Ghana [43,44]. Obesity is an independent risk factor for CKD and was identified in 21.4% of participants in the Ghana report. However, screening for CKD in patients with pre-existing risk factors provides a higher yield of CKD diagnoses and is a better indicator of the need to change treatment when compared with population-based screening for CKD [45]. The development of CKD needs to be considered as a lifelong risk and determining the presence of risk factors in childhood is essential for prevention programmes and CV risk tracking. A report from Ghana found that hypertension was present in 3.5% of school children (average age 8.9 years) and obesity in 9.8%, similar to other countries [46]. Similarly, in South Africa, obesity/overweight was identified in 20% of supposedly healthy 5-9 year olds, pre-hypertension in 14%, and hypertension in 22% [47]. In this report, adiposity and elevated BP was more common in the White and Black ethnic groups, respectively. Salt intake is a further concern that has been found to contribute to hypertension and CKD. It was estimated that sodium intake contributed to 1.5% of deaths in 2012 and 0.7% of DALYs in South Africa [48].