Severity of obesity and management of hypertension, hypercholesterolaemia and smoking in primary care: population-based cohort study

Abstract

Obesity and obesity-associated cardiovascular risk are increasing worldwide. This study aimed to determine how different levels of obesity are associated with the management of smoking, hypertension and hypercholesterolaemia in primary care. We conducted a cohort study of adults aged 30-100 years in England, sampled from the primary care electronic health records in the Clinical Practice Research Datalink. Prevalence, treatment and control were estimated for each risk factor by body mass index (BMI) category. Adjusted odds ratios (AOR) were estimated, allowing for age, gender, comorbidity and socioeconomic status, with normal weight as reference category. Data were analysed for 247,653 patients including 153,308 (62%) with BMI recorded, of whom 46,149 (30%) were obese. Participants were classified into simple (29,257), severe (11,059) and morbid obesity (5833) categories. Smoking declined with the increasing BMI category, but smoking cessation treatment increased. Age-standardised hypertension prevalence was twice as high in morbid obesity (men 78.6%; women 66.0%) compared with normal weight (men 37.3%; women 29.4%). Hypertension treatment was more frequent (AOR 1.75, 1.59-1.92) but hypertension control less frequent (AOR 0.63, 0.59-0.69) in morbid obesity, with similar findings for severe obesity. Hypercholesterolaemia was more frequent in morbid obesity (men 48.2%; women 36.3%) than normal weight (men 25.0%; women 20.0%). Lipid lowering therapy was more frequent in morbid obesity (AOR 1.83, 1.61-2.07) as was cholesterol control (AOR 1.19, 1.06-1.34). Increasing obesity category is associated with elevated risks from hypertension and hypercholesterolaemia. Inadequate hypertension control in obesity emerges as an important target for future interventions.

Figure 1

Use of antihypertensive drugs by BMI category. Proportion of hypertensive patients receiving different classes of antihypertensive drugs.

Figure 2

Treatment and control of hypertension by BMI category in 2011. Bars represent the proportion of hypertensive patients who received treatment and those with a blood pressure measurement of <140/90 mm Hg.

Figure 3

Treatment and control of hypercholesterolaemia by BMI category in 2011. Bars represent the proportion of patients with hypercholesterolaemia who received the treatment and those with a total cholesterol measurement of ⩽5 mmol l⁻¹.