Cardiovascular diseases (CVD) formerly considered as developed countries pandemic, are becoming nowadays increasingly ubiquitous in developing countries, where in addition to a steady increase in different risk factors, there is substantial inaccessibility to health care. However, data about the burden of CVD is lacking in many sub-Saharan African countries, and their morbimortality characteristics have been poorly described. Authors carried out a descriptive and retrospective study over a 12-month period, to describe the inhospital morbidity and mortality of CVD in the Department of Internal Medicine at University Teaching Hospital in Kigali City. Data were collected from 226 CVD cases (91 males and 135 females). The patients’ age ranged from 26 to 94 years (mean age of 47.17 ± 16.04). The 226 CVD cases account for the 8.2% of hospitalized patients. Hypertension was the principal cause of death (43.1% of deaths) and the predominant cause of patients’ admission (42.9%), followed by cardiomyopathies (11.9%) and valvular heart diseases (11.5%). The association between a CVD and HIV/AIDS infection was observed in 23.9% of the total patients, but no causality relationship was investigated. Isolated heart failure takes the first place (33.6%) among the cardiovascular complications, followed by stroke (14.2%) and isolated renal failure (7.5%). Findings of this study confirm the importance of CVD in CHU Kigali, not only by their inhospital frequency but also- and especially by their lethality rate and their complications associated. This study stresses also a real need of CVD community survey in Rwanda. Keywords: Cardiovascular disease, cardiomyopathy, HIV/AIDS, morbidity, mortality, Rwanda, sub-Saharan Africa.
Cardiovascular diseases (CVDs) represent more than a half of noncommunicable diseases [1] and a major public health problem all over the world because of their high morbidity and mortality [1],[2] and by related economic impact on health expenditures. [3] Among a total of 58 millions deaths registered worldwide in 2005, noncommunicable diseases represented 35 millions, and among these, 17.5 millions (50.8%) were attributable to CVDs. [4] The CVDs were therefore qualified as the first cause of death worldwide [1],[5] and is set to overtake infectious diseases in the developing world in term of morbidity and mortality. [2],[6] It has been discussed in the literature that, the increase of cardiovascular incidence in modern society is associated to the aging, however in sub-Saharan Africa (SSA) countries where life expectancy is still low, the CVDs burden seem to be related to life style change, epidemiologic transition and therefore an increase of exposure to different risk factors associated with CVDs.[7] The emerging cardiovascular risk factors linked to modernization accounts for the growing burden of CVD in SSA, are challenged by deficient and/or insufficient infrastructure and thus experiencing inadequate health care. [6],[8],[9] According to World Health Organization (WHO) 2005, these epidemiologic transition linked factors are responsible for 75% of all CVDs [10] and hence constitute a priority because of their impact on the increasing cardiovascular morbidity and mortality, [11],[12],[13] as well as the possibility of modifying them by effective preventive measures. [1],[14] In developing countries moreover, the access to health care facilities being still difficult, [15],[16] there is delay in diagnosis, leading to a late treatment, and to a very difficult follow-up; [17],[18] justifying among other causes – the high morbidity and mortality rates associated with CVDs. [14],[16] In contrast to other low setting places, [11],[19],[20],[21],[22] inhospital studies in Rwanda to evaluate the current situation of CVDs are still scarce. [23] The authors are not aware of any community-based cardiovascular survey which should have been conducted in Rwanda. The one published paper reported an hospital data in 2001 at Butare University Hospital [14] and during this study the literature search listed six other hospital unpublished data. [24],[25],[26],[27],[28],[29] The aim of this study is to investigate the epidemiologic, clinical, and prognostic features of CVDs in the department of internal medicine at CHU Kigali.
A descriptive and retrospective study was carried out at University Teaching Hospital of Kigali, namely ‘Centre Hospitalier Universitaire (CHU) de Kigali’- Internal Medicine Department, in Kigali City, between January 1, 2005 and December 31, 2005 (12 months). Data were collected from patients’ records admitted for cardiovascular problems in the medical wards. Files for patients transferred from the medical wards to the Intensive Care Unit, during the study period, were reviewed as well. All patients aged below 15 years, ambulatory patients and patients not diagnosed with CVD were excluded from the study. A questionnaire was used for data collection. The following parameters were systematically collected: age, sex, residence, socio-professional category, medical and family past history, clinical signs/symptoms on admission, time between appearance of first signs/symptoms and the start of treatment, diagnosis, type of CVD, treatment received, complications, inhospital stay duration, and patient’s prognosis at discharge. Data entry and analysis were realized using EpiData and SPSS 11.5.
Epidemiologic features Out of 2858 patients, the total number of patients admitted in the Department of Internal Medicine, 226 were admitted for cardiovascular problems. Hence, the cardiovascular in hospital frequency was 8.2%. The patient’s in hospital stay period ranged between 1 and 120 days with a mean range of 15 ± 23 SD days. The follow-up noticed a mortality of 581 (20.3%) cases, of whom 67 (27 males and 40 females) were attributable to CVDs. The inhospital cardiovascular mortality rate by CVD is 2.34% (67/2858); where as the cardiovascular fatality rate is 29.6% (67/226). The patients’ age ranged from 16 to 94 years with a mean age of 47.17 ± 16.04 SD years. There were 91 males (40.3%) and 135 females (59.7%) with a sex ratio M/F of 0.67. CVD were more frequent in females than in males (59.7% females vs. 40.3% males) and people in the age range of 46-60 years were the most affected (25.2%). However, the frequency of 24.3% in the younger population is surprising [Table 1]. In all age groups, gender is not associated with cardiovascular morbidity [Table 1], except in advanced age where men are more affected than women ( P = 0.031). Clinical and diagnostic features Medical history Fifty-four (23.9%) patients were HIV positive. For 45 cases (19.9%) cases whose past medical history was not known. As the time between the appearance of the first symptom and start of treatment is analyzed, the study found that 41.6% of patients begun the treatment within 2 weeks vs. 26.5% who begun it 2 months or more, after appearance of the first symptoms. Clinical signs of CVDs Vertigo, respiratory distress, cough, chest pain, and headache were the most frequent clinical signs/symptoms with respective frequencies of 70.8%, 54.9%, 52%, 50.9%, and 50%. The study found that 23% of the patients presented with generalized edema. Arterial Hypertension (HT) was found to be the most common diagnosis at admission day (42.9%). Other early diagnoses included cardiomyopathies (11.9%), valvular heart disease (11.5%), pericarditis (8%), vascular disease (7.1%), and others (11%). Therefore, 7.5% patients were admitted for heart failure of unknown etiology. The outcome of those patients is dominated by recovering (70.1%). However, inhospital-specific mortality for CVD was high (29.6%) [Table 2]. The HT was the principal cause of death (43.1%), followed by heart failure of unknown etiology (16.4%). According to this early diagnosis, heart failure is the only one which is statistically associated with a high-mortality rate ( P < 0.001); other cases of mortality are not statistically significant [Table 2]. Evolution and complications Of all the patients whose records were analyzed, 61 (27%) did not present complications [Table 3]. Heart failure isolated or associated with other organ failures (renal, neurologic, and pulmonary) was the predominant complication (33.6% in the isolated form). Multiple organ failure accounted for 11.9% [Table 3]. Over 67 patients who died, 22 (32.8%) had multiple organ failure or isolated heart failure. The overall occurrence of complications is directly linked to mortality ( P < 0.001); multiple organ failure being particularly a lethal condition (22/27 = 81.4% of patients with multiple organ failure had premature/in-hospital death) ( P < 0.001). The other relationships are shown in [Table 3]. The high proportion of mortality (61.2% of patients who died) was observed in patients aged 45 years or more. People aged 61-75 years were the most represented (35.8%). Moreover, mortality is found to be statistically correlated to advanced age ( P = 0.02). Heart failure alone or associated to other organ failure (which was almost the case) is linked to mortality ( P < 0.001); however, isolated episodes of heart failure during hospitalization were not found to be associated with high mortality ( P = 0.87). This shows that patients with heart failure who die have very often other organ damage.
The inhospital frequency of CVDs in the Department of Internal Medicine at CHU Kigali was 8.2% during the study period. This frequency complies with the margin of 5-12% reported in SSA by Bertrand. [19] Therefore, it is slightly lower than the 16% reported in Netherlands in 2005 by Reitsma et al. [30] and that of 24.2% reported in Shanghai (China) in 2003 by Chen et al . [31] The mean age in our series was 47.17 ± 16.04 SD years. This mean is comparable to the one of 46.8 years reported by Mboulley and Bouelet in Cameroun. [21] This finding however, shows the importance of CVDs in younger population in sub-Saharan countries compared to western countries where it has been established that CVDs occur at older age with a mean age of 67 ± 12 SD years. [32] In this western countries population, ageing should explain the relatively high CVD prevalence and mortality rates. [7],[33],[34] In the present study, 54 (23.9%) patients admitted for CVD were HIV positive. This finding, similar to African reports, [35],[36] shows the impact of HIV/AIDS epidemic to the increasing prevalence of different types of CVD in our settings including cardiomyopathy, [23] pericardial disease, [37] other cardiac manifestations of HIV infection associated or not with opportunistic infections, [3],[18] infectious endocarditis, [19] neoplasia, and pulmonary hypertension. [36],[37],[38],[39],[40] However, no causality relationship has been investigated in our series. The study also found that 41.6% of patients begun the treatment within 2 weeks whereas 26.5% begun it 2 months or later, after the occurrence of initial clinical signs. The mean period between the occurrence of clinical signs and the start of treatment was 118 days. The delay in treatment in our patients is responsible for the importance of complications and the poor prognosis of CVDs. The low sanitary and education levels of our patients, the inaccessibility to health care and the inadequate structure of the reference systems in our health centers would be the major aspects to consider while resolving this problem. CVDs occur as follows: HT is the predominant cause of patients’ admission (42.9%), followed by cardiomyopathies (11.9%) and valvular heart disease (11.5%); other causes include pericarditis (8%), heart failure of unknown etiology (7.5%), vascular disease (7.1%), etc. These findings are similar to those in reports from many African authors: Mboulley and Bouelet in Cameroun [21] reported the following distribution: arterial hypertension: 38.5%; valvular heart disease: 25.6%; cardiomyopathies: 22.5%; other cardiopathies: 13.5%. In the discussed Tchadian series reported by Twagirumukiza, [14] arterial hypertension represented 58% of the total CVDs. This situation seems to be particular to Africa because, Chen et al. in China [31] found the coronary heart disease (CHD) to be the first cause of patients’ admission (39.1%). In Europe, CHD remains the predominant cause of morbidity and mortality in adults among the CVDs.[8],[19],[31],[41] The predominance of hypertension among blacks has been widely discussed; [42],[43] this trend has been recognized since early in this century. In a cohort study started in the 1970s, hypertension accounted for 20% of all-cause mortality among blacks, compared to 10% among whites. [42] Causes and real figures on the African continent are being discussed including genetic factors, salt sensitivity, arterial stiffness, and others. Another point to make about African series is the age of occurrence of CVD which is too lower compared to western societies. [14],[19],[43],[44] In our series, valvular heart disease, infectious endo/myocarditis, and pericarditis are observed in the younger population (reaching their maximum before 40 years). The absence of many cases of infectious endo/myocarditis and the occurrence of cases of heart failure with unknown etiology would be explained by two facts: the limited accurate diagnostic tools and the delayed period of patients’ admissions. The relatively high incidence of cardiomyopathies, pericarditis, and nutritional CVD would explain the association of these pathologic conditions with the HIV/AIDS infection. The high incidence of valvular heart disease (11.5%) explains the insufficiency of prevention of these conditions in developing countries. [14],[45],[46] Hence, they remain a challenge in our settings because of limited sources in accurate diagnostic and therapeutic tools (cardiac surgery for instance) and the occurrence of complications associated with them. [4] Concerning complications, only 61 (27%) patients did not present complications. Isolated heart failure (33.6%) was the predominant complication; followed by stroke (14.2%) and isolated renal failure (7.5%). Multiple organ failure represented 11.9%. These findings are similar to those found by Mouanodji in Tchad reported by Twagirumukiza [14] where isolated heart failure came first (27.96%), followed by stroke (9.32%) and isolated renal failure (3.3%), multiple organ failure occupied 33% whereas CVD did not present any complication in 26% cases. This shows how CVDs are associated with high-morbidity rate and hence, constitute an important burden in developing countries. In the present study, the CVD lethality rate was 29.6%. However this figure is limited to hospital follow up since it was not possible to follow our patients after their discharge. The lethality rate of 29.6% can be compared to that of 25.9% reported in 2002 by Thiam in Senegal; [22] whereas it is higher as compared to reports from Mouanodji [14] (16%). Limited number of trained personnel in cardiology, lack of accurate diagnostic and therapeutic tools, drugs availability, prices and affordability, as well as delayed patients’ admission would explain the higher cardiovascular fatality rate at CHU Kigali. Similar to other reports, this study observed that the inhospital mortality due to CVDs complicated with multiple organ failure was very high (in our study, 81.4% patients with multiple organ failure died). This study identified furthermore, the occurrence of complications ( P < 0.001) and the advancing age of patients ( P = 0.020) as potential risk factors to poor prognosis. As other hospital studies, this paper findings are biased by hospital settings: the hospital prevalence is influenced by the rate of utilization of health services in Rwanda. This is a real limitation of this study because the Rwanda as other developing countries has a very low rate of utilization of health services due to population poverty, culture, habits, and education. Therefore, most of CVDs never reach the hospital, and the prevalence at hospital should be underestimated compared to the real burden in population. Another limitation is hospital performance to diagnose CVDs (equipment, professional skills, and patient affordability which could contribute to underestimate the prevalence).
Findings of this study confirm the importance of CVDs in CHU Kigali, not only by their in hospital frequency (8.2%), but also – and especially, by their lethality rate (29.6%) and their complications. The majority of deaths were associated with complications (91%) and advanced age (61.2%). The hypertensive-related diseases are the leading causes of death (43.1%) and most frequent cause of patients’ admission (42.9%). The most frequent complication was heart failure followed by stroke. Within patients with complications group, more than one quarter complications consisted in multiorgan damage. In one quarter of followed patients, the CVD was associated to HIV/AIDS. The setup of health education mechanisms and early adequate management can reduce the incidence of complications and lower mortality associated with CVDs.
Source of Support: None, Conflict of Interest: None
Clinical trial registration None
[Table 1], [Table 2], [Table 3] |
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