P5482The lipid paradox in patients with non-ST elevation and ST elevation myocardial infarction and percutaneous coronary intervention

Background/Introduction

Elevated levels of low-density lipoprotein (LDL-C) and triglycerides (TG) are well-described risk factors for the development of acute myocardial infarction (MI). Despite these well-established associations, previous studies have described the existence of a “lipid paradox” in acute MI patients – Patients paradoxically have worse outcomes despite having lower LDL-C and TG levels.

Purpose

We conducted this study to clarify the relationship of the lipid paradox and clinical outcomes amongst non-ST elevation (NSTEMI) and ST elevation MI (STEMI) patients in patients who have had percutaneous coronary intervention.

Methods

We included all acute MI patients reported to the Singapore Myocardial Infarction Registry from 2007 to 2013 who have had percutaneous coronary intervention. This information was linked to the national claims database to obtain the final discharge diagnosis for re-hospitalization outcomes. Exposure of interest was the lipid profile obtained within 72 hours of the acute MI (LDL-C, TG; Total cholesterol [TC]; high-density lipoprotein [HDL-C]). Primary outcomes were all-cause mortality during hospitalization, within 30-days and within 1-year. Secondary outcomes were re-hospitalization within 1-year for heart failure, stroke and MI.

Results

There were 8988 NSTEMI and 12453 STEMI cases available for analysis (n=21441). The NSTEMI patients were older (60.3 years vs 57.6 years, p<0.001) and more likely to be female (15.1% vs 22.6%, p<0.001). In the NSTEMI subgroup, a lower LDL-C was paradoxically associated with better outcomes for death during hospitalization, death within 30 days from MI onset and death within 1 year from MI onset (all p<0.001) across the various LDL-C levels. Adjustment for demographic variables, co-morbidities and MI characteristics eliminated this paradox. However, in the STEMI subgroup, the lipid paradox for LDL-C persisted for all primary outcome endpoints after adjustment. In the STEMI patients, a lower HDL-C also appeared to be protective. An elevated TG level did not appear to be protective in both NSTEMI and STEMI patients after adjustment.

Conclusion(s)

An elevated LDL-C appears to be a protective prognostic marker in STEMI but not NSTEMI patients who have undergone percutaneous coronary intervention. This difference may be due to differing underlying pathophysiological mechanisms between the 2 populations.

Obesity prevention and management: Singapore's experience

Singapore's obesity prevalence among adult Singapore residents aged 18-69 increased from 6.9% (2004) to 10.8% (2010). Among school-going children, the prevalence of overweight and severely overweight (body weight > 120% standard weight for height) increased from 1.4% (1976) to 12.7% (2006) for primary 1 students, and 2.2% to 15.9% for primary 6 students. Fundamentally, obesity is a function of excess energy intake (food consumption) and insufficient energy expenditure (physical activity). In 2010, about 40% did not have sufficient physical activity, and about 60% consumed excess energy. For students in the mainstream schools, only a fifth consumed at least two servings of fruits and vegetables every day, and a tenth were physically active for at least 60 min on 5 or more days a week. From a public health perspective, the most powerful levers for influencing population health lie in interventions that make healthy living convenient and an unconscious choice by targeting the social and environmental context. Recognizing this, the Health Promotion Board has in recent years made a strategic shift away from just public education campaigns aimed at individual behaviours, to focus on creating a ground-up social movement to enable and empower individuals to live out a healthy lifestyle.

The Singaporean response to the SARS outbreak: knowledge sufficiency versus public trust

During the outbreak of severe acute respiratory syndrome (SARS) in Singapore from 1 March to 11 May 2003, various national prevention and control measures were undertaken to control and eliminate the transmission of the infection. During the initial period of the epidemic, public communication was effected through press releases and media coverage of the epidemic. About a month into the epidemic, a public education campaign was mounted to educate Singaporeans on SARS and adoption of appropriate behaviours to prevent the spread of the disease. A survey was conducted in late April 2003 to assess Singaporeans' knowledge about SARS and infection control measures, and their concerns and anxiety in relation to the outbreak. The survey also sought to assess their confidence in the ability of various institutions to deal with SARS and their opinion on the seemingly tough measures enforced. The study involved 853 adults selected from a telephone-sampling frame. Stratified sampling was used to ensure adequate representation from major ethnic groups and age groups. The study showed that the overall knowledge about SARS and control measures undertaken was low (mean per cent score of 24.5 ± 8.9%). While 82% of respondents expressed confidence in measures undertaken by Tan Tock Seng Hospital (the hospital designated to manage SARS), only 36% had confidence in nursing homes. However, >80% of the public agreed that the preventive and control measures instituted were appropriate. Despite the low knowledge score, the overall mean satisfaction score of the government's response to SARS was 4.47 (out of possible highest score of 5.00), with >93% of adult Singaporeans indicating that they were satisfied or very satisfied with the government's response to SARS. Generally, Singaporeans had a high level of public trust (satisfaction with government, confidence in institutions, deeming government measures appropriate), scoring 11.4 out of possible maximum of 14. The disparity between low knowledge on the one hand and high confidence and trust in the actions of the government on the other suggests that Singaporeans do not require high knowledge sufficiency to be confident in measures undertaken by the government to control the SARS crisis.

Breastfeeding prevalence and practices among Singaporean Chinese, Malay and Indian mothers

The National Breastfeeding Survey 2001 was the first comprehensive study on breastfeeding conducted on a national level in Singapore. It aimed to establish the prevalence of breastfeeding among Chinese, Malay and Indian mothers and to identify factors influencing breastfeeding. A total of 2098 mothers were interviewed in this two-phase study, with the first interview conducted 2 months after delivery and the second interview 6 months after birth among mothers who were still breastfeeding at 2 months. Frequency distributions of breastfeeding prevalence and types of breastfeeding practices at different time intervals (from birth to 6 months) were produced. Multivariate logistic regression was carried out to construct a model with predictive information on factors which influence continued breastfeeding till 2 months and 6 months after delivery respectively. The study found that about 94.5% of the mothers attempted breastfeeding. At 1 month, 71.6% were still breastfeeding, 49.6% continued to do so at 2 months, and 29.8% persisted till 4 months. By 6 months, the breastfeeding prevalence rate fell to 21.1%. The results of this study show higher breastfeeding prevalence rates compared to past studies in Singapore. Despite this, exclusive breastfeeding is still not a common practice. Various factors were found to be significant in influencing mothers' decision to breastfeed. Factors such as ethnicity, age, educational attainment, religion and baby's sex are non-modifiable in the short term or at an individual level. However, factors such as awareness of breastfeeding benefits, advice from health professionals and previous breastfeeding experience are potentially modifiable. Efforts aimed at promoting breastfeeding in Singapore need to take these modifiable factors into consideration so as to better tailor health promotion efforts on breastfeeding to women.