[The effect of antihypertensive therapy on the seasonal variations in arterial pressure in hypertensive patients].

To evaluate the influence of antihypertensive therapy (AHT) on blood pressure (BP) seasonal variations, we have analyzed the systolic and diastolic BP values in 145 hypertensives, 112 males and 33 females, aged 23-65 years, in the 10-year period 1981-1990. All patients received medical treatment and were examined for at least 5-7 consecutive years. The year was divided in 2 (cold and warm months) and 4 periods in relation to mean monthly environmental temperature (10 degrees C, 13 degrees C, 18 degrees C and 23 degrees C). Systolic and diastolic BP was higher in cold months (142/93 vs 137/88 mmHg, p less than 0.05). In cold periods AHT was increased in 11% of patients and decreased in 8%. In the warm periods AHT was decreased in 11% of patients and increased in 6%. The AHT reduction in the warm months was not significantly different in comparison to that of cold months. Vice versa, the AHT increase in cold months was greater than that of warm periods (p less than 0.001). In the 10-year period considered, 18% of patients reduced AHT in the warm period and increased it in the cold period. It was also found a small correlation between diastolic blood pressure and wind, which is, in our country, mostly the mistral. Betablockers, calcium-antagonists and the association betablocker-diuretics showed a seasonal BP variation, while patients treated by diuretic had the same BP both in winter and in summer. A small negative correlation was observed between systolic and diastolic BP and temperature in patients treated by all antihypertensive drugs except the diuretics.(ABSTRACT TRUNCATED AT 250 WORDS)