Our work found a statistically significant positive correlation between mortality and diabetes mellitus (r = 0.685), renal failure (r = 0.705), chronic heart diseases (0.591), COPD (r = 0.523), malignancy (r = 0.692), kidney transplantation (r = 0.644) and liver cirrhosis (r = 0.525) (P < 0.05), (Table 3) .