Tuesday , November 21 2017
Home / Conditions / Obesity / Cause of Low Mortality Rate from Coronary Heart Disease

Cause of Low Mortality Rate from Coronary Heart Disease

Increase in BMI and A1c leads to coronary issues.

Obesity and diabetes have surpassed other cardiovascular risk factors such as hypertension, dyslipidemia and tobacco use in terms of prevalence in the U.S. Evidence-based medicine and use novel drugs such as thrombolytics, ACE inhibitors and statins, use of special heart procedures such as heart valves, pacers, stents and percutaneous coronary intervention have led to great improvements in the treatment of cardiovascular disease.

This study examines trends in death due to coronary heart disease in the two decades between 1980 and 2000. A validated IMPACT mortality model was applied to determine how coronary heart disease-related deaths among adults in the U.S. was influenced by risk factors such as smoking, dyslipidemia, obesity, diabetes mellitus, lack of physical activity, and surgical interventions for coronary heart disease.

Data of deaths was obtained from the National Vital Statistics System of the National Center for Health Statistics. Mortality rate due to CHD in 1980 was extrapolated to the year 2000 while considering the aging population. Number of deaths avoided in 2000 was calculated by subtracting the actual deaths in 2000 from the number calculated. For therapies that were available over the two decades, the net benefit was calculated by subtracting the number of deaths avoided in 1980 from the number of deaths in 2000. Full compliance was assumed for patients who underwent inpatient treatment while symptomatic and asymptomatic outpatients were assumed to be 70% and 50% compliant respectively.

Regression analysis was used to determine the number of deaths avoided due to changes in hypertension, cholesterol, and obesity. Effects of changes in tobacco use, diabetes, and lack of physical activity was based on a population risk factor, which depended on prevalence and relative risk of death from CHD due to the risk factor. Number of deaths avoided was arrived at by finding the product of the difference between population attributable risk factor in both 1980 and 2000 multiplied by the number of deaths from CHD in 1980.

Between 1980 and 2000, the CHD-related death rate among men decreased from 543/100,000 to 267/100,000 and from 263/100,000 to 134/100,000 among women. The study also reports total deaths from CHD in 1980 as 462,984 among people ages 25 to 84 years while in 2000 there was a total of 337,658 CHD-related deaths in the same age group. This shows a reduction in the death rate in 2000 compared to 1980, which is attributable to the changes in medical treatments and changes in risk factors.

Medical therapies helped avoid about 159,330 CHD-related deaths, the majority of which were prevented through secondary prevention therapies either after angina episodes or revascularization. Death was also avoided by treating STEMI episodes, heart failure, hypertension, dyslipidemia, and chronic MI. Revascularization prevented 5% of the total deaths in 2000 compared to 1980 while the reduction in risk factors (smoking, cholesterol and hypertension) helped avoid about 149,635 CHD-related deaths.

Despite the decrease in the mortality rate between 1980 and 2000, cardiac heart disease remains the highest killer disease in U.S. The period between 1980 and 2000 experienced a spike in technological growth and research geared toward the treatment of CHD and reduction of risk factors.

In conclusion, the largest contribution from medical therapies was from secondary prevention such as the treatment of acute coronary syndrome, revascularization, and treating heart failure. The fall in CHD-related deaths over the two decades from 1980 to 2000 was due to risk reduction and use of newer, improved, and well-researched treatment strategies.

Practice Pearls:

  • Reduction in risk factors such as smoking, hypertension, and dyslipidemia prevented additional deaths due to CHD between 1980 and 2000.
  • Secondary preventive therapies such as treating MI, revascularization, and heart failure helped avoid CHD-related deaths between the two decades.
  • Increases in BMI and diabetes mellitus lead to an increase in CHD related deaths.

References:

  1.   Ford ES, Ajani UA. Croft JB. et al. Explaining the Decrease in U.S. Deaths from Coronary Disease, 1980–2000. N E J Med 2007; 356:2388-2398 DOI: 10.1056/NEJMsa053935
  2.      Hedley AA, Ogden CL, Johnson CL, Carroll MD, Curtin LR, Flegal KM. Prevalence of overweight and obesity among US children, adolescents, and adults, 1999-2002. JAMA 2004; 291:2847-2850

 

Josephat Macharia, PharmD candidate, Lecom School of Pharmacy class of 2018