Diagnostic evaluation of people with hypertension in low income country: cohort study of "essential" method of risk stratification.

OBJECTIVES: To explore the predictive power of a risk stratification method for people with hypertension based on "essential" procedures (that is, available in economically less developed areas of the world), comparing it in the same population with the results given by the method suggested by the 1999 World Health Organization-International Society of Hypertension (WHO-ISH) guidelines. DESIGN: Prospective cohort study of outcomes according to cardiovascular risk profile at baseline. SETTING: Primary care in a poor rural area of the Ecuadorian forest. PARTICIPANTS: 504 people with hypertension prospectively monitored for a mean of 6.7 (SD 2.3) years. INTERVENTIONS: Essential data included blood pressure, medical history, smoking, age, sex, and diagnosis of diabetes; the WHO-ISH methods additionally included measurement of fasting blood glucose, total cholesterol, and creatinine, urinalysis, and electrocardiography. MAIN OUTCOME MEASURES: Cardiovascular events and total deaths. RESULTS: With both methods there was a highly significant association between the level of predicted risk and the incidence of cardiovascular events and of total deaths: up to three quarters of all cardiovascular events and two thirds of all deaths were reported among people classified as at high or very high risk with either method. The predictive discrimination of the essential method is comparable with the WHO-ISH with C statistics (95% confidence interval) of 0.788 (0.721 to 0.855) and 0.744 (0.673 to 0.815), respectively, for cardiovascular events and 0.747 (0.678 to 0.816) and 0.705 (0.632 to 0.778) for total mortality. CONCLUSIONS: The risk stratification of patients with hypertension with an essential package of variables (that is, available and practicable even in the economically less developed areas of the world) serves at least as well as the more comprehensive method proposed by WHO-ISH.

Treatment and control of arterial hypertension in a rural community in Ecuador.

Cardiovascular diseases are widespread in developing countries, but little is known about cardiovascular risk profiles in rural communities. To assess the importance of arterial hypertension in a rural district of Ecuador, we screened 4284 of the 8876 adults who lived in the area. 1542 (36%) individuals had hypertension, only four (0.3%) of whom were well controlled by treatment. We monitored all deaths for 2.5 years, and noted that cardiovascular diseases were the primary cause of death in the adult population. Furthermore, of the individuals who died of a cardiovascular disease, four out of five had a history of hypertension. Our findings indicate that in this rural area of Ecuador the high prevalence of uncontrolled hypertension is a major cause of total mortality.

Amebic infections due to the Entamoeba histolytica-Entamoeba dispar complex: a study of the incidence in a remote rural area of Ecuador.

An epidemiologic field study was conducted in the village of Borbòn in Esmeraldas province in northern Ecuador to compare different parasitologic methods in the diagnosis of infection with the Entamoeba histolytica/Entamoeba dispar complex. The results of two stool antigen detection assays (the Prospect Entamoeba histolytica microplate assay and the E. histolytica II assay) were compared with isoenzyme characterization of the amebic isolates. Nearly all (176 of 178, 98.9%) subjects were positive for intestinal parasites on direct microscopic examination, and cysts and/or vegetative forms morphologically consistent with the E. histolytica/E. dispar complex were recorded in 48 of 178 cases (27%). Culture in Robinson's medium was positive for amebic stocks in 89 (50%) of the 178 samples tested. Of the 37 isolates successfully stabilized, cloned, and characterized by zymodeme analysis, seven (18.9%) showed isoenzyme patterns of E. histolytica, whereas 26 (70.3%) showed patterns of E. dispar. The remaining four strains were identified as Entamoeba coli (three isolates; 8.1%) and Dientamoeba fragilis (one strain; 2.7%).The immunochromatographic tests showed different degrees of sensitivity and specificity when compared with isoenzyme characterization as the reference technique. The microplate assay, which does not discriminate between E. histolytica and E.dispar, showed a sensitivity of 54.5% and a specificity of 94% for both these amebic species. In contrast, the second-generation E. histolytica II test had a sensitivity of 14.3% and a specificity of 98.4% for E. histolytica sensu stricto. Our survey clearly demonstrated that more specific and sensitive diagnostic tests, such as stool antigen detection assays and isoenzyme analysis, are needed to establish the actual worldwide distribution of E. histolytica and E. dispar.