Introduction
The modern era brings new health challenges, the booming rate of obesity, especially in moderate-income to high-income countries, is one of the major public health issues of the 21st century.1 It is a multifactorial complex disease defined as a body mass index (BMI) of more than 30 kg/m2 as an indicator of an excessive accumulation of body fat or increased adiposity.2 3 The prevalence of obesity has reached an epidemic proportion in certain population segments and it has been reported to be directly or indirectly associated with an increased risk of premature deaths.4–6
In addition to the metabolic risk, obesity is a well-established risk factor with a direct or indirect role in the progression and development of cardiovascular diseases (CVD).6 The direct mode of action is through function and structural alterations to the heart induced by increased adiposity.6 7 The indirect mode of action is through its strong association with the well-established risk factors for CVD, which included atherosclerosis, diabetes mellitus, metabolic syndrome, hyperlipidaemia, hypertension and obstructive sleep apnoea.6–8 Several pathophysiological mechanisms for obesity-related cardiac structural and functional alterations have been postulated, which included, reduced insulin sensitivity or insulin resistance, hypercoagulability state, cytokine activation, neuro-hormonal changes, lipotoxicity, oxidative stress, and chronic inflammation.5 6 9–11
A widely acceptable aetiological explanation of obesity is the ‘chronic positive energy balance’, which means lesser expenditure and higher energy intake.10 Emerging patterns of multiple dietary and lifestyle factors can be attributed to the increasing burden of obesity in our societies. These factors mainly include ‘poor dietary choices’ characterised by excessive calorie intake and ‘sedentary lifestyle’ characterised by massive declines in physical activity (occupational/non-occupational).8 10 12
On one hand, obesity is reported to be associated with an increased risk of development and progression of CVD, and on the other hand, in several studies, it has been observed to play a paradoxical role characterised by favourable immediate-term, short-term and long-term outcomes in obese CVD patients as compared with their non-obese counterparts, commonly known as the ‘obesity paradox’.3 11 13–15 On the other hand, various studies have also negated the existence of the ‘obesity paradox’ at all or its existence is limited to particular subgroups, such as the elderly age group, female patients or patients with intact regenerative capacity.3 13 16–18 Hence, considering the geographical variations in the epidemiology of obesity,19 it is important to understand this phenomenon in a geographical context. Therefore, in this study, our aim was to evaluate the existence of an ‘obesity paradox’ in a South Asian cohort of patients with ‘ST-segment elevation acute coronary syndrome (STE-ACS)’ presented to a tertiary cardiac care hospital in Pakistan.