Usual blood pressure, peripheral arterial disease, and vascular risk: cohort study of 4.2 million adults

Abstract

Objectives: To determine the subgroup specific associations between usual blood pressure and risk of peripheral arterial disease, and to examine the relation between peripheral arterial disease and a range of other types of vascular disease in a large contemporary cohort.

Design: Cohort study.

Setting: Linked electronic health records from 1990 to 2013 in the United Kingdom.

Participants: 4,222,459 people aged 30-90 years, registered at a primary care practice for at least one year and with a blood pressure measurement.

Main outcome measures: Time to first diagnosis of new onset peripheral arterial disease and time to first diagnosis of 12 different vascular events.

Results: A 20 mm Hg higher than usual systolic blood pressure was associated with a 63% higher risk of peripheral arterial disease (hazard ratio 1.63, 95% confidence interval 1.59 to 1.66). The strength of the association declined with increasing age and body mass index (P<0.001 for interaction) but was not modified by sex or smoking status. Peripheral arterial disease was associated with an increased risk of 11 different vascular events, including ischaemic heart disease (1.68, 1.58 to 1.79), heart failure (1.63, 1.52 to 1.75), aortic aneurysm (2.10, 1.79 to 2.45), and chronic kidney disease (1.31, 1.25 to 1.38), but not haemorrhagic stroke. The most common initial vascular event among those with peripheral arterial disease was chronic kidney disease (24.4% of initial events), followed by ischaemic heart disease (18.5% of initial events), heart failure (14.7%), and atrial fibrillation (13.2%). Overall estimates from this cohort were consistent with those derived from traditional studies when we pooled the findings in two meta-analyses.

Conclusions: Raised blood pressure is a strong risk factor for peripheral arterial disease in a range of patient subgroups. Furthermore, clinicians should be aware that those with established peripheral arterial disease are at an increased risk of a range of other vascular events, including chronic kidney disease, ischaemic heart disease, heart failure, atrial fibrillation, and stroke.

Fig 1 Adjusted hazard ratios of systolic blood pressure and diastolic blood pressure for incident peripheral arterial disease by age. Adjustments were for body mass index, smoking status, sex, baseline diabetes, and baseline antihypertensive and lipid lowering drug use, and the interaction between age as a categorical variable and systolic and diastolic blood pressures as categorical variables, respectively. Confidence intervals are displayed as floating absolute risks. Hazard ratios are plotted at the mean of each usual systolic blood pressure and usual diastolic blood pressure category

Fig 2 Adjusted hazard ratios of 20 mm Hg higher usual systolic blood pressure for incident peripheral arterial disease stratified by patient subgroup. Adjustments were for age, body mass index, smoking status, sex, baseline diabetes, and baseline antihypertensive and lipid lowering drug use. For subgroups of age, adjustment was also for the interaction between systolic blood pressure and age category. For subgroups of sex, adjustment was also for the interaction between sex and systolic blood pressure. For subgroups of body mass index, adjustments were also for the interaction between systolic blood pressure and body mass index category. For subgroups of smoking, adjustments were also for the interaction between systolic blood pressure and smoking status

Fig 3 Adjusted hazard ratios of baseline peripheral arterial disease versus no peripheral arterial disease for 12 different vascular events. Adjustments were for age, body mass index, smoking status, sex, baseline diabetes, baseline antihypertensive and lipid lowering drug use, and baseline peripheral arterial disease