Hypertension and obesity Dr Wilson Sugut Moi teaching and referral hospital
No conflict of interests to declare
Obesity Definition: excessive weight that may impair health BMI Categories Underweight BMI < 18.5 Normal weight = 18.5-24.9 Overweight = 25-29.9 Obesity type I = BMI 30-34.9 Obesity type II= BMI 35-39.9 Extreme obesity type III BMI >40
Prevalence Worldwide obesity has nearly doubled since 1980 and current estimates indicate that >1.4 billion adults are overweight or obese. In USA, at least 65% of adults are overweight, one third of adults are obese Several other countries report even higher rates of obesity some exceeding 50% eg Tonga, Qatar. Prevalence of child obesity has also risen rapidly in parallel with increasing obesity in adults
Developing countries Prevalence of overweight and obesity increasing 20 50% of urban poppulations in Africa are obese/overweight. Rates of overweight/obesity higher in women compared with men and urban compared with rural dwellers Predictors in SSA include SES age Parity marital status physical inactivity body weight perceptions
Zarabi et al 2009
Metabolic Syndrome Waist circumference 102 cm (40 inches) for men 88 cm (35 inches) for women Blood pressure 130 mm Hg systolic and/or 85 mm Hg diastolic Fasting glucose 110 mg/dl or 6.1 mmol/l Triglycerides 150 mg/dl or 1.69 mmol/l HDL cholesterol 40 mg/dl (1.04 mmol/l) in men 50 mg/dl (1.29 mmol/l) in women
Body weight and BP Higher BMI is associated with increased risk for development of hypertension over time. On average obese individuals are 3.5 times more likely to develop HTN Relative 10 Year Risk for Hypertension Stratified by Baseline BMI BMI HTN 18.5 21.9 1 22 24.9 1.5 25 29.9 2.4 30 34.9 3.8 >35 4.2 Jnc 7
75 and 65% of hypertension in men and women are attributable to obesity. Adiposity stands out as a major controllable contributor to hypertension.
Waist circumference is more closely linked to cardiovascular disease risk factors than is BMI. Zhu et al. Am J Clin Nutr 2002 A central distribution of body fat is associated with increased BP, independently of body mass index. Siani et al. Am J Hypertens 2002
Risks associated with hypertension Regardless of the cause hypertension causes 2 to 3 fold increase in all CVD events combined RR with hypertension are greatest for stroke and HF Risk for CVD death increases in a continuous fashion at SBP levels starting as low as 115 mm Hg and DBP 75 mm
Predicted 10 year risk for coronary heart disease
Joint Effects of Obesity and Hypertension on CVD Risk ( Chicago Heart Association Detection Project in Industry cohort)
Factors Linking Obesity to Hypertension
Putative mechanisms of obesity induced hypertension Not fully understood Sympathethic nervous system activation Renal and adrenal mechanisms Activation of RAAS Impaired endothelial function Adipokines Insulin resistance
Treatment of Obese Hypertensive Patients
Weight reduction 1. Lifestyle interventions Low cost, minimal risk Nutrition Physical activity Behavioural changes Mean fall in blood pressure of 6.3/3.4 mmhg with weight loss diets. Continue for 6 months before considering pharmacological therapy.
2. Pharmacotherapy BMI >30 or >27 in a person with obesity associated complication Used together with lifestyle modifications 5 drugs FDA approved, 3 monotherapies and 2 combination therapies Orlistat,lorcaserin and Liraglutide monotherapies Phentermine topiramate and naltrexone bupropion 1 year pivotal trial 5.8 8.8kg weight loss for the monotherapies and 6 10kg for combination therapies
3. Bariatric surgery Gastric banding 15 20% weight loss in year less efficacious Roux en y bypass procedure 25%weight loss in 1 year Sleeve gastrectomy involves removes approx. 70% of stomach. Accelerates gastric emptying. 25 30% wt loss in 1 yr.
Treatment of Hypertension General principles not different from non obese patients Caveats; 1. Thiazides effective but watch metabolic adverse events. 2. ARBs/ACEI increase insulin sensitivity and reduce diabetic risk 3. BB associated with wt gain and negative effects on glucose metabolism
Treatment of hypertension Target: 140 90 Renin angiotensin aldosterone system inhibition ACEI/ ARBs Diuretics Low dose thiazide or thiazide like agent Loop diuretics (if required) Potassium sparing agents CCBs Avoid b blockers except for specific cardiac indication
SUMMARY AND RECOMMENDATIONS Obesity is an important risk factor for hypertension and all-cause mortality. Weight loss can lead to a significant fall in blood pressure. Antihypertensive agents will often be necessary if adequate weight loss cannot be achieved or sustained. Angiotensin converting enzyme inhibitors, angiotensin blockers, or dihydropyridine calcium channel blockers antihypertensive agents of choice. receptor may be the