Hepatitis C virus (HCV) infection is a major problem affecting about 180 million people worldwide, or roughly 3% of the world’s population is currently infected. The burden of disease is greatest in developing countries: the highest reported prevalence is in, Egypt (22%), Pakistan (4.8%) and China (3.2%). HCV infection is one of the major causes of end-stage liver disease and hepatocellular carcinoma (HCC) worldwide. Cirrhosis rates become significant after 20�years of HCV infection. About 20-30% of patients could develop a progressive liver disease leading to cirrhosis and HCC. HCC develops at about 1-7% per year. This study aims to determine the common prevalent HCV genotypes among chronic HCV patients in Sana'a - Yemen and to evaluate the rate of sustained virological response (SVR) with some factors that affecting it. The study population includes all the 500 patients with chronic HCV infection who were treated in different hospitals during the period February 2010- August 2013. Epi –Info 7 was used to calculate the sample size, it was decided to use a simple random sampling technique in this study and a random sample of 88 patients were selected with confidence level of 99%, the sample size was then increased to 120 to maximize accuracy of the study, later 20 patients dropped out of the study & data of only 100 patients was analyzed. Each specimen was determined for HCV genotyping and HCV RNA viral load was measured before, after 12 weeks, 48 weeks and 6 months after stopping the treatment. In our study, the most predominant genotype was genotype IV with 86 %, 9 % genotype I followed by 5 % genotype II, 86 patients were investigated, after 12 weeks of treatment, 39 of them ( 45.3% ) were HCVRNA –ve, after 48 weeks of the treatment, some remained HCV-RNA –ve and others turned into HCVRNA +ve, but overall 39 patients (45.3%) were HCV-RNA –ve and after 6 months of stopping the treatment, 23 out of 39 (58.9 %) achieved SVR, i.e. 26.74 % of the total sample (n = 86) achieved SVR. Regarding the effect of SVR according to gender, in this study, it showed that 84.2% of females had a SVR compared to 35% of males only (p.value of 0.003) , our study also showed that there is no statistical difference between SVR and various age groups, as it showed that 100% of those >45 years old who had a +ve HCV-RNA after 6 months from stopping treatment while 68.4 % of the age groups 30-45 years old & 58.8% of the age group < 30 years old had a –ve HCVRNA after 6 months from stopping treatment.(p.value of 0.082). We found out that only 2.6 % of those who had +ve HCV RNA after 6 months from stopping the treatment were overweight, and there was no statistical difference in SVR between normal and overweight groups according to Body Mass Index (BMI) measuring , it showed that 60.5 % of those with normal BMI had a SVR.(p.value of 0.41), In our study, there is statistical difference in SVR between those who had low (66.6%) and high viral load (16.6%) (P. value 0.033) and also there was statistical significance between EVR after 12 weeks and SVR after 6 months of stopping treatment (P value = 0.0) , 23 out of 25 patients ( 92%) who had Early virological response (EVR) persist to have SVR . In our study, the most predominant genotype was genotype IV with 86 %. Of our HCV-treated patients, 58.9% had SVR. HCV genotype-4, EVR, and low baseline viral load were predictive of SVR.
