Aggressive modification of known CHF risk factors is critical for the primary prevention of CHF. However, although some common risk factors, including diabetes mellitus, hypertension and coronary artery disease et al., have been explored in previous population-based studies, early identity of individuals who have higher risk for developing CHF is still difficult, especially for the general population without apparent cardiovascular diseases. Orthostatic hypotension, described as abnormal fall in blood pressure on standing, has been observed to be prevalent in both the elderly and the middle-age population. Although individuals with OH are often asymptomatic, evidence from several epidemiologic studies indicated that these subjects are associated with increased risk of future CVD or mortality. Recently, some prospective cohort studies have found a significant association between OH and risk of incident CHF, while the findings have not always been consistent. Therefore, we performed a multiple egf fbn1 gene important cell adhesion meta-analysis to provide an overview of relevant studies and to provide an overall quantitative estimate of predictive ability of OH for CHF. Moreover, we tried to clarify which subgroups of subjects with OH are at higher risk for incident CHF. The definitions of OH in each study were consistent with the consensus of the international statement, although there were a little difference concerning the timing for measurements of SBP and DBP in standing position. Since some of the studies reported the association between OH and CHF risk according to the age range, sex, hypertension status and DM status of the participants, we combined these data to investigate whether these characteristics of the participants could affect the association between OH and CHF. In this meta-analysis, by pooling the results of all available prospective cohort studies, we found that subjects with presence of OH were associated with about 30% higher risk of CHF incidence compared with those without OH at baseline. 
We also found that association between OH and increased CHF risk seemed to be significant in middle-age participants, and in those with hypertension or DM, but not significant in the elderly subjects, or in those without hypertension or DM. These results confirmed the hypothesis that individuals with OH, even without other CVD or risk factors, are at high risk for development of CHF in the future. Although several previous cross-sectional studies have shown that presence of OH is independently related to left ventricular hypertrophy confirmed by electrocardiogram or echocardiography, the exact mechanisms underlying the significant predictive effect of OH for development of CHF are not known. Besides, at this stage, we can’t decide whether or not OH was causally related to CHF and whether or not OH was only a marker of a generally increased risk of CHF incidence. Several suggested mechanisms may be helpful to understand the relationship between presence of OH and increased risk for future CHF, of which autonomic dysfunction is an interesting one. It has been well recognized that baroreflex dysfunction probably induced by impairment of baroreceptor due to aging or atherosclerosis, is one of the most important causes of OH. Indeed, when subjects stand up from a supine position, blunted baroreceptor may fail to deactivate the baroreflex and the vagal output therefore can not be down-regulated, leading to OH. On the other side, dysfunction of baroreflex has also been observed in CHF patients. Impaired baroreceptor may fail to activate the baroreflex in CHF patients with hemodynamic stress, and the sympathetic tone maintained activation, which has been accepted as an important mechanism underlying the pathogenesis and progression of CHF.