CARDIOVASCULAR JOURNAL OF AFRICA • Volume 34, No 3, July/August 2023 146 AFRICA second most common cause of global deaths and has the highest prevalence, incidence and case fatality in SSA.36 Hypertension remains its pre-eminent modifiable risk factor, as discussed above.37,38 Optimal control of hypertension would significantly reduce the burden in SSA. We found a heart failure mortality rate of 14.0% during the period under review, with 34.8% of these deaths occurring within the first seven days of admission. Heart failure death rates in Nigeria ranged between 8.1 and 13.1%.27,54,55,62 In the THESUSHF study, the heart failure mortality rate was 4.2%.49 In the USA, stroke and heart failure accounted for 16.8 and 9.4%, respectively, of all CVD deaths in 2017.63 These are much lower than the rates in Nigeria and corroborate the globally held view that CVD rates are on the decline in the HICs but on the increase in LMICs.64,65 Socio-epidemiological factors such as ignorance, healthcare inequalities, poverty, higher prevalence of risk factors, poor access to healthcare, in addition to the huge simultaneous burden of infectious and poverty-related morbidities account for the disparate CVD death rates between Nigeria/LMICs and the HICs.57,65,66 HDx and ACS were minor contributors to both admissions and deaths during the period under review. Globally, SSA still has the lowest rate of coronary heart disease.67 From our study, ACS was not a common contributor to CVD admissions in Nigeria, accounting for 1.6% of overall CVD admissions. Several studies in Nigeria have reported ACS admission rates ranging from 0.2 to 1.6%.29,30,68,69 Falase et al.70 reported a prevalence of 2.8% of angiographically confirmed coronary heart disease in Lagos. In SSA, ACS rates are reported to be between 0.8 and 10.8%.71 Despite the low rate, our study showed a galloping rise in cases of ACS, with a peak increase of 900% in 2012, which remained sustained until 2015, suggesting that indeed the burden of ACS is on the increase. This rising burden may be causally related to the huge prevalence of CVD risk factors in Nigeria. It is also believed that inadequate diagnostic and treatment resources, in addition to inadequate expert manpower, may account for the lower rates of reported cases of ACS in Nigeria.65 With an improvement in knowledge and awareness of ACS among general practitioners, prompt referral to coronary care units, and availability and accessibility of diagnostic resources, reported cases of ACS might become more prevalent in future. Strengths and limitations The strength of this study lies in the 16 years it covered. To the best of our knowledge, it was able to demonstrate the burden and temporal trends of CVD admissions more so than any similar study in SSA has done. Our study however has some limitations. First it is a hospitalbased study and may not reflect the true burden of the disease. From an epidemiological point of view, population-based studies are the gold standard for understanding the burden of diseases and their determinants. In Nigeria and in most SSA, these studies are sparse due to problems of logistics, lack of reliable databases and registries and the high cost of implementing them. However, hospital-based studies are easier to carry out and therefore more common and provide indirect evidence of the burden of a disease in the general population in the absence of a population-based study. Second, the data for the study were extracted from manually stored hospital records, which sometimes are fraught with clerical errors (missing/incomplete/ improperly recorded data) in the absence of electronic medical records. This may have affected our results. Conclusion Our study was able to demonstrate a rising trend of CVD admissions and deaths over a 16-year period. Stroke and heart failure were the major contributors to admissions and deaths, while temporal trends showed that ACS had the highest exponential rate of increase. Although this was a hospitalbased study, it is a mirror of the CVD pattern in the general population. Hypertension remains the most important driver of CVD in Nigeria and frequently aggregates other sanctionable risk factors such as obesity, diabetes, dyslipidaemia and physical inactivity. With rising prevalence of these risk factors, inequities in healthcare access and an ageing population exposed to unhealthy westernised lifestyle, the burden of CVD will continue to be high in the years ahead. Strategies with large ‘effect sizes’ aimed at prevention and control of these risk factors would significantly stem the tide of CVD in Nigeria and indeed SSA. The authors thank Drs Naomi Samuel Udonsak and Marius Ibe for assisting in data collection, and Clement Akinsola and Chimamaka Duke for their secretarial assistance. References 1. World Health Organization. Prevention of cardiovascular disease: Guidelines for assessment and management of cardiovascular risk. Geneva. Switzerland, 2010. 2. 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