We sought to describe the profile of heart diseases among adult patients referred for echocardiography in a semi-urban setting of Cameroon. Hypertension accounted for over half of the comorbidity among these patients. Hypertension remains a driver of cardiovascular diseases burden in SSA [5, 13, 14].
Hypertensive heart disease was the leading type of heart disease in our setting, accounting for 41.1 %. This is similar to findings of Tchoumi and Bureta conducted in a rural setting of the Northwest Region [11] and other semi-urban and urban settings in Cameroon [9–11, 17]. Given the high hypertension rates in the general Cameroonian population [18], coupled with the contrastingly poor awareness, treatment and control rates [16, 18–20], our findings were expected. Similar findings have been reported in other SSA series [7, 21, 22]. However, our results differ from studies conducted in East Africa. For example, in an Ethiopia study, valvular heart disease was the commonest heart disease [23]. In addition, pericardial diseases were the main types of heart disease in a Malawian study [24]. This discrepancy could be due to the relatively younger population in the Ethiopian study [23]. Indeed, rheumatic heart disease which is a significant cause of VHD in SSA is a disease of children and adolescents [25]. An early diagnosis of hypertension, treatment and, most importantly close follow up on treatment could significantly delay the occurrence of hypertensive heart disease in our setting. In addition, Of the 93 patients who presented with mixed cardiopathies, hypertensive heart disease associated mixed cardiopathies were still the most common 61 (65.6%).
Valvular heart disease was the second most common type of heart disease in our setting. It accounted for 11.7% of the study population, and of these only 5.8% was secondary to rheumatic heart disease. More than half of reported cases were related to degenerative processes. Our findings are contrary to those of Jingi et al and Nkoke et al of the West and Southwest regions of Cameroon respectively, who reported cardiomyopathies as the second leading type of heart disease [9, 10]. Even though rheumatic heart disease remains a major public health issue in Cameroon and SSA as a whole, it seems to be relatively scarce in our study setting. This could be explained by the fact that rheumatic heart disease occurs in a relatively young population and people aged < 30 years represent only 8.3% of our study population. Nonetheless, 1.1% of all cases of heart disease was secondary to RHD in our study, which is relatively lower than 3.4% reported by Jingi et al in the West Region [10].
The relatively lower proportion of post rheumatic valvulopathies could also be explained by the fact that being a hospital-based study, cases which were not clinically evident and those who could not afford a cardiac ultrasound did not feature in the study. In addition, the fact that there are no available internationally standardised guidelines for the diagnosis of RHD in adults [26] might have contributed to an underestimation of the true prevalence of the disease in this study, especially as over 90% of our study population was at least 30 years old.
The prevalence of cardiomyopathies was 6.8%, and they were the third commonest type of heart disease in our setting. Dilated cardiomyopathy remained the most common type of cardiomyopathy, accounting for 77.2 % of cardiomyopathies. Our findings differ from those reported in the South West and West regions of the Cameroon [9, 10] in that cardiomyopathies were the third and not second most frequent type of heart disease in our setting. Though dilated cardiomyopathies were still the major types of cardiomyopathies, Hypertrophic cardiomyopathies were the second most common cardiomyopathies with a proportion of 21.4%.
The spectrum of pericardial disease in our study is relatively lower than that reported by Jingi et al in West Cameroon and relatively higher than that reported by Nkoke et al in the South West Cameroon [9, 10]. However, findings in Malawi report pericardial diseases as the leading burden of heart disease; associating it to the coinciding HIV epidemic.
The most common type of pericardial disease in our context was the pericarditis with effusion, of which 20% were associated to tuberculosis.
It is worth noting that up to 13.9% of our study population was diagnosed with more than one heart disease, what we termed mixed cardiopathies. To the best of our knowledge, this is the first study in Cameroon which reports a population with patients having more than one heart disease. This is important knowledge necessary in the diagnosis, management and prognosis of heart diseases in our context.
Heart failure occurred in 17.5% of study population, with HHD (33.1%), CMO (22.9%) and VHD (17%) responsible for over 70% of the cases. Mixed cardiopathies significantly contributed to HF in our study.
The proportionately more males with heart failure in our study is similar to that reported by Kingue et al in the General Hospital of Yaoundé, Cameroon [27]. However, There is a gender disparity between our study and findings in the Heart Of Soweto study in South Africa and the Abuja Heart study in Nigeria where females formed the greater proportion of the population with heart failure [28, 29].
According to a recent review, HF was reported as a disease of the middle-aged adult, occurring between the third and fifth decades of life, as opposed to the developed world where it is essentially a disease of the elderly, occurring in the seventh decade of life [6]. In addition, HHD, CMO and VHD were the leading causes of HF [6]. Though our findings still maintain hypertensive heart disease as the leading cause of heart failure in our study population, they differ from existing knowledge in that valvular heart diseases are the third commonest causes. Given that hypertensive heart disease arises as a complication of longstanding systemic hypertension on the heart, with its increasing prevalence in SSA, the importance of early prevention and proper treatment of hypertension in our context cannot be over emphasized. Rheumatic heart disease instead was a rare cause of heart failure here probably accounted for by the age limit of our population. Nonetheless, mixed cardiopathies formed a sizeable proportion of the aetiologies of heart failure in our context.