Impact of Non-Ischemic Dilated Cardiomyopathy in Tanzania

Abstract

In the general introduction in Chapter 1, we noted dual existence of communicable diseases with emergent non-communicable diseases in Tanzania which are alarmingly on the rise. We also observed the high prevalence of cardiovascular risk factors (CRF) such as hypertension and obesity in the community. Additionally, we observed that NIDCM is a common cause of heart failure (HF) and found in all age groups and across all regions of SSA. Literature reveals distinctive presentation in SSA due to socio-demographics, environmental and potentially genetic factors compared to what is reported in high income countries. In Chapter 2, the systematic review of NIDCM in SSA explored the magnitude of the condition in the region and assess associated risk factors. There were wide variations in prevalence of NIDCM in the region which was compounded with the non-uniform definition of NIDCM. Notwithstanding, we established that NIDCM is a common condition in patients with HF in SSA. We failed to identify any studies that focused on the interaction of NIDCM and established CRF. This observation called for a further look into CRF and NIDCM which formed the rationale for installing the MOYO (characterization of non-ischeMic dilated cardiomyOpathY in a native Tanzanian cOhort) cohort. With the MOYO cohort in Chapter 3, we observed in our cohort a slight male predominance, with majority of patients presenting clinically advanced New York Heart Association (NYHA) class and severe systolic dysfunction. While most cases were due to idiopathic or presumed hypertensive cardiomyopathy, at least one in every ten patients had PPCM. Despite the advanced disease in the majority of patients, the use of ESC guidelines recommended medications was suboptimal. Family screening of 57 first degree relatives of patients with idiopathic NIDCM is presented in Chapter 4. Despite challenges due to low turn up of the family for screening as well as the lack of access to other diagnostic modalities used in family screening; we identified 14.1% of screened family members to have previously unknown NIDCM. They were predominantly young, most often female and all of them asymptomatic. In Chapter 5, the outcome after a mean follow up of 19±7months, 60% of the cohort of 402 patients were alive, one fifth had died and nearly another fifth was lost to follow up (LTFU). Use of device implant was extremely low. Severe systolic dysfunction on echocardiography recorded at baseline was an independent predictor of mortality outcome. In Chapter 6, we conclude that NIDCM is among the leading cardiovascular cause of morbidity and mortality in the most productive age of the population in Tanzania, and yet there is inadequate control of CRF and limited access to care. Furthermore, the underlying etiologies and socio-demographics characteristics from what has been described in HIC, calling for tailored diagnostic and management protocol suitable for the Tanzanian and possibly SSA population. We recommend comprehensive screening programs, the establishment of tailored management protocols, and an exploration into the genetic underpinnings NIDCM in Tanzania.