Strong independent association between obesity and essential hypertension.

Obesity and hypertension (HTN) are major risk factors for cardiovascular disease. Association between obesity and HTN has not been studied in a large populations following adjustment for comorbidities. The goal of this study was to evaluate any association between obesity and HTN after adjusting for baseline characteristics. We used ICD-9 codes for obesity and HTN from the Nationwide Inpatient Sample (NIS) databases. Two randomly selected years, 1992 and 2002, were chosen from the databases as two independent samples. We used uni- and multivariable analysis to study any correlation between obesity and HTN. The 1992 database contained a total of 6,195,744 patients. HTN was present in 37.2 % of patients with obesity versus 12% of the control group (OR: 4.36, CI 4.30-4.42, P < 0.001). The 2002 database contained a total of 7,153,982 patients. HTN was present in 50.7% of patients with obesity versus 25.6% of the control group (OR: 2.98, CI 2.96-3.00, P < 0.001). Using multivariable analysis adjusting for gender, hyperlipidaemia, age, smoking, type 2 diabetes and chronic renal failure, obesity remained correlated with HTN in both years (1992: OR 2.69, CI 2.67-2.72, P < 0.001; 2002: OR 2.98, CI 2.96-3.00, P < 0.001). The presence of obesity was found to be strongly and independently associated with HTN. The cause of this correlation is not known warranting further investigation.