Background The baseline characteristics of patients in a multinational trial are possibly related to cardiovascular outcome.This study compared the baseline Characteristics of patients recruited in China with those recruited in other countries.Methods A total of 508 Chinese hypertensive men and 728 women over the age of 80 years who entered the Hypertension in the Very Elderly Trial(HYVET)were compared with those in 860 men and 1 348 women who entered the trial in other countries.Results The Chinese subjects were slightly younger,had less previous hypertension but more previous strokes than the subjects from other countries.The Chinese subjects smoked more than those from other countries,but drank less alcoho1.They had less previous episodes of myocardial infarction and were,on average,lighter and shorter.The Chinese had lower mean concentrations of blood urea,uric acid and creatinine as well as higher concentrations of high density lipoprotein(HDL)cholesterol.The concentration of total cholesterol was,on average,lower in the Chinese subjects as was blood glucose.The levels of serum sodium and potassium,blood hematocrit and hemoglobin were all,on average,lower in the Chinese subjects.Conclusions Calorie restriction,compared with the rest of the world,may have resulted in lower stature and weight, and recent increases in calorie intake have not changed the metabolic profile of the very elderly hype~ensive patients in China.Some of these biochemical differences may reflect different dietary lifestyle in the Chinese.