Abstract 639: Blood Pressure Response To Patterns Of Weather Fluctuations And Effect On Mortality
Background: Very few studies have looked at longitudinal BP changes in relation to weather variation. There is no data to suggest that specific BP response to changes in weather have an impact on survival.
METHODS: We analysed >169000 clinic visits of 16000 Glasgow BP Clinic hypertensive patients. Each clinic visit was mapped to the mean West of Scotland monthly weather (temperature, sunshine, rainfall) from meteorological data. Analyses were restricted to pairs of consecutive clinic visits where the weather alternated between two extreme quartiles (Q1->Q4 or Q4->Q1) or remained in the same quartile (Qn->Qn) of each weather parameter. The BP phenotype analysed was the percent change in SBP and DBP between two consecutive clinic measurements at least 30 days apart and within each year. The %ΔBP between groups were tested using paired-T tests. Subjects were categorised into two groups depending on Q1->Q4 or Q4->Q1 BP response compared to Qn->Qn (concordant or discordant). Generalised estimating equations and Cox proportional hazards model were used to model the effect on longitudinal BP and mortality respectively.
Results: For temperature, visits Qn->Qn showed a mean 2% drop in BP consistently while Q4->Q1 showed a mean 4% rise in SBP and Q1->Q4 elicited variable changes in BP around 0. Compared to subjects with a concordant BP response to temperature, those who showed a discordant response had significantly higher mortality (1.35 [95% CI :1.06-.71];p=0.01) and higher follow-up SBP (1.85 [0.24-3.46]; p=0.02).
Conclusions: Variation in weather has a complex relationship to longitudinal BP and response to weather fluctuations is a predictor of long-term risk and BP control.
- © 2012 by American Heart Association, Inc.