Abstract
Background
The prevalence of obesity has increased markedly over the past four decades; however, some reports suggest a recent plateau. There is little information available regarding recent changes in obesity prevalence among patients hospitalized with cardiovascular disease.
Objective
To define obesity trends among patients hospitalized with cardiovascular disease between 2002 and 2009 at an academic medical center.
Methods
This is a retrospective database analysis of patients admitted with cardiovascular diagnoses in 2002 versus 2009. Using ICD-9 codes, the study population was generated. Body mass index (BMI) was calculated by dividing weight in kilograms by height in meters squared (Quetelet index). Patients were assigned to 1 of 5 BMI categories: normal weight (BMI < 19–24.99), overweight (BMI 25–29.99), Grades I obesity (BMI 30–34.99), Grade II obesity (BMI 35–39.99), and Grade III obesity (BMI >40). Patient demographics are compared with Student’s T-tests for continuous data and χ2 tests for categorical data. Logistic regression models were developed in the overall cohort to ascertain differences in obesity grades I, II & III between the two time points with age, gender, race and primary ICD-9 code included as covariates. The logistic regression models were then repeated for each primary ICD-9 code.
Results
Patients admitted with cardiovascular diagnoses in 2002 (n=1271) and 2009 (n=1576) were stratified by BMI categories. Over this period of nine years, obesity prevalence increased significantly from 28.5% to 38.4% of patients. In particular, Grades II and III obesity increased markedly from 2002 to 2009 (7.6% versus 9.9%, and 2.7% versus 7.5%; unadjusted p= 0.04, p<0.001 and adjusted p=0.09 and p<0.0001 respectively). Individuals with Grade III obesity had a higher incidence of arrhythmias, coronary heart disease, and valvular heart disease.
Conclusions
Grade II and III obesity has markedly increased among patients admitted to our hospital with major cardiovascular diagnoses in the period 2002 to 2009. With respect to hospitalized patients, the obesity epidemic is still on a steeply rising trajectory, especially for the extremely obese categories.
Introduction
A recent analysis of the National Health and Nutrition Examination Survey (NHANES) data suggested that there was no significant change in obesity prevalence in the past 10 years for men or women in the United States1 including severe (grades II and III) obesity.2 Notwithstanding, over this same time period, we have documented a marked increase in severe obesity in our cardiovascular (CV) ultrasound imaging laboratory3 and have subjectively noted an apparent increase in grades II and III obesity among patients admitted to our hospital with CV diagnoses. The objective of this study was to determine temporal trends in obesity prevalence (particularly grades II and III) in patients hospitalized with CV diagnoses in the period 2002 to 2009.
Methods
A retrospective database analysis was performed using the Saint Luke’s Health System billing records database after obtaining approval from the Saint Luke’s Hospital (Kansas City, Missouri) Institutional Review Board. A list of patients admitted with CV diagnoses in 2002 and 2009 was generated using ICD-9 diagnoses codes. Based on ICD-9 codes, patients were further grouped into five categories: arrhythmias, myocardial infarction (MI), valvular heart disease (VHD), peripheral arterial disease (PAD), heart failure (HF) and other (See Table 1). The height and weight measured using standardized techniques and equipment during initial evaluation on admission were recorded. Body mass index (BMI) was calculated by dividing weight in kilograms by height in meters2 (Quetelet index).4 Based on BMI, patients were assigned to 1 of 5 BMI categories (normal weight BMI 19–24.99, overweight BMI 25–29.99, Grade I obesity BMI 30–34.99, Grade II obesity BMI 35–39.99, and Grade III obesity BMI >40).
Table 1.
ICD-9 codes used to identify patients with cardiovascular diagnoses in 2002 and 2009.
| Cardiovascular Diagnoses | ICD-9 codes | |
|---|---|---|
| Disease of Tricuspid Valve, Mitral valve and aortic valve | Valvular Heart Disease | 394, 395, 396, 397, 398, 424, 424.1 |
| Atherosclerosis of native arteries of extremities, intermittent claudication, aortic aneurysm, cerebrovascular accident, transient ischemic attack | Peripheral Arterial Disease | 414, 440.20, 440.21, 441, 444.21 and 444.22 |
| Congestive heart failure | Heart Failure | 405, 425, 428 |
| Conduction disorders, cardiac dysrhythmias | Arrhythmias | 426, 427 |
| Acute myocardial infarction | Myocardial Infarction | 410 |
| Arterial embolism | Other | 420, 423 |
Patient demographics are displayed for the entire cohort and compared between the 2002 and 2009 time points with Student’s T-tests for continuous data and χ2 tests for categorical data. Logistic regression models were developed in the overall cohort to ascertain differences in obesity grades I, II & III between the two time points with age, gender, race and primary ICD-9 code included as covariates. The logistic regression models were then repeated for each primary ICD-9 code. Statistical significance was defined as P≤0.05. All statistical analyses were performed by the Saint Luke’s Mid America Heart Institute Department of Biostatistics using SAS Version 9.2 (SAS Institute, Cary, NC).
Result
There were 2,847 patients admitted with various CV diagnoses in 2002 (n= 1271) and 2009 (n=1571). Demographics of the overall cohort and patients stratified by time are displayed in Table 2. Average age at the time of hospitalization in 2002 was 67 ± 13.3 years versus 66.1 ± 15.8 years in 2009 (p=0.099). There was no statistically significant gender or racial variation between the two groups (See Table 2). The average BMI for the patient population in 2002 was 28.6 ± 5.6 kg/m2 compared to 29.3 ± 6.8 kg/m2 in 2009 (p< 0.001 adjusted and unadjusted p-value). In 2002, 28.5% of patients were obese (grade I to grade III); by 2009, obesity prevalence had increased to 38.4% of patients (p<0.001). Grades II and III obesity prevalence increased markedly from 2002 to 2009 (7.6% versus 9.9% and 2.7% versus 7.5%; unadjusted p= 0.04, <0.001). After adjustment for baseline characteristics the odds ratio for Grade III obesity in 2009 versus 2002 was 2.74 (95% CI 1.84–4.08, p <0.0001) (See Tables 3 and 4).
Table 2.
Patient Demographics
| Total n = 2847 |
Year | P-Value | ||
|---|---|---|---|---|
|
| ||||
| 2002 n = 1271 |
2009 n = 1576 |
|||
|
| ||||
| Age | 66.5 ± 14.3 | 67.0 ± 13.3 | 66.1 ± 15.1 | 0.099 |
|
| ||||
| Men | 1848 (64.9%) | 840 (66.1%) | 1008 (64.0%) | 0.236 |
|
| ||||
| Caucasian | 2491 (87.5%) | 1127 (88.7%) | 1364 (86.5%) | 0.089 |
|
| ||||
| Weight | 187.4 ± 46.5 | 182.2 ± 42.3 | 191.6 ± 49.2 | < 0.001 |
|
| ||||
| BMI | 28.6 ± 6.3 | 27.8 ± 5.6 | 29.3 ± 6.8 | < 0.001 |
|
| ||||
| Normal | 775 (27.2%) | 378 (29.7%) | 397 (25.2%) | 0.007 |
|
| ||||
| Overweight | 1048 (36.8%) | 502 (39.5%) | 546 (34.6%) | 0.008 |
|
| ||||
| Obesity | 968 (34.0%) | 363 (28.6%) | 605 (38.4%) | <0.001 |
|
| ||||
| Primary ICD-9 | <0.001 | |||
|
| ||||
| Arrhythmias | 494 (17.4%) | 317 (20.1%) | ||
| MI | 443 (15.6%) | 177 (13.9%) | 353 (22.4%) | |
| PAD | 1348 (47.3%) | 90 (7.1%) | 613 (38.9%) | |
| VHD | 378 (13.3%) | 735 (57.8%) | 199 (12.6%) | |
| HF | 153 (5.4%) | 179 (14.1%) | 76 (4.8%) | |
| Other | 31 (1%) | 77 (6.1%) 13(1%) | 18 (1.2%) | |
BMI=body mass index, MI=myocardial infarction, PAD=peripheral arterial disease, VHD=valvular heart disease, HF=heart failure.
Table 3.
Frequency of grades I to III obesity (unadjusted) among patients with various cardiovascular disorders.
| Cardiovascular Diagnoses | Obesity Grades | Year 2002 | Year 2009 | P value |
|---|---|---|---|---|
| All | Grade 1 | 233 (18.3%) | 335 (21.3%) | 0.052 |
| Grade II | 96 (7.6%) | 152 (9.6%) | 0.049 | |
| Grade III | 34 (2.7%) | 118 (7.5%) | <0.001 | |
| Arrhythmias | Grade 1 | 31 (17.5%) | 67 (21.1%) | 0.333 |
| Grade II | 12 (6.8%) | 25 (7.9%) | 0.654 | |
| Grade III | 7 (4.0%) | 33 (10.4%) | 0.012 | |
| Myocardial Infarction (MI) | Grade I | 22 (24.4%) | 78 (22.1%) | 0.634 |
| Grade II | 4 (4.4%) | 36 (10.2%) | 0.089 | |
| Grade III | 2 (2.2%) | 20 (5.7%) | 0.276 | |
| Peripheral Arterial Disease (PAD) | Grade I | 142 (19.3%) | 132 (21.5%) | 0.315 |
| Grade II | 52 (7.1%) | 74 (12.1%) | 0.002 | |
| Grade III | 15 (2.0%) | 38 (6.2%) | <0.001 | |
| Valvular Heart Disease (VHD) | Grade I | 26 (14.5%) | 45 (22.6%) | 0.044 |
| Grade II | 19 (10.6%) | 45 (22.6%) | 0.024 | |
| Grade III | 4 (2.2%) | 14 (7.0%) | 0.029 | |
| Cardiomyopathy | Grade I | 11 (14.3%) | 10 (13.2%) | 0.839 |
| Grade II | 7 (9.1%) | 5 (6.6%) | 0.563 | |
| Grade II | 6 (7.8%) | 12 (15.8%) | 0.125 | |
| Other | Grade I | 1 (7.7%) | 3 (16.7%) | 0.621 |
| Grade II | 2 (15.4%) | 3 (16.7%) | 1.000 | |
| Grade III | 0 (0.0%) | 1 (5.6%) | 1.000 |
Table 4.
Frequency of grades I to III obesity (adjusted) among patients with various cardiovascular disorders.
| ICD-9 | Obesity | OR | p-value |
|---|---|---|---|
| All | Grade I | 1.18 (0.98–1.42) | 0.0881 |
| Grade II | 1.26 (0.96–1.66) | 0.0924 | |
| Grade III | 2.74(1.84–4.08) | <0.0001 | |
| Arrhythmia | Grade I | 1.29 (0.8–2.08) | 0.2938 |
| Grade II | 1.1 (0.53–2.27) | 0.805 | |
| Grade III | 2.59 (1.11–6.06) | 0.0276 | |
| Myocardial Infarction (MI) | Grade I | 0.89 (0.52–1.54) | 0.6781 |
| Grade II | 2.26 (0.78–6.56) | 0.1352 | |
| Grade III | 2.51 (0.57–11.15) | 0.226 | |
| Peripheral Arterial Disease (PAD) | Grade I | 1.16 (0.89–1.52) | 0.2725 |
| Grade II | 1.69 (1.16–2.46) | 0.0067 | |
| Grade III | 2.89 (1.55–5.37) | 0.0008 | |
| Valvular Heart Disease (VHD) | Grade I | 1.66 (0.97–2.83) | 0.0651 |
| Grade II | 0.37(0.16–0.86) | 0.02 | |
| Grade III | 3.44(1.1–10.76) | 0.0341 | |
| Cardiomyopathy/Heart failure (HF) | Grade I | 0.89 (0.35–2.27) | 0.8101 |
| Grade II | 0.65 (0.19–2.21) | 0.4904 | |
| Grade III | 1.87 (0.63–5.59) | 0.2598 | |
| Other | Grade I | 2.08 (0.17–25.4) | 0.566 |
| Grade II | 1.74 (0.19–15.74) | 0.6207 | |
| Grade III | NA* | 0.9464 |
N/A: Not estimated
A subgroup analysis revealed a statistically significant increase in the prevalence of grade III obesity in patients with diagnoses of arrhythmias, PAD and VHD in 2009 versus 2002 (p=0.012 for arrhythmia group, p < 0.001 for PAD group and p=0.029 for VHD group). The adjusted p value for grade III obesity was significant for arrhythmias (OR 2.59, 95%CI [1.11–6.06] p = 0.0276), PAD (OR 2.89, 95%CI [1.55–5.37] p = 0.0008) and VHD (OR 3.44, 95%CI [1.1–10.76] p = 0.0341) (See Tables 3 and 4).
Discussion
In this study, we have observed a marked increase in the prevalence of Grade II and III obesity among patients hospitalized with CV diagnoses at Saint Luke’s Mid America Heart Institute from 2002 to 2009. Obesity is a complex disorder influenced by environmental and genetic factors. Once considered a problem of developed countries, the World Health Organization (WHO) now estimates that the overweight and obese population is dramatically rising in developing countries as well. In 2005, approximately 1.6 billion adults (age 15+) were overweight, and at least 400 million adults were obese.5 It has been estimated that by 2015, approximately 2.3 billion adults will be overweight and more than 700 million will be obese.5
Obesity is associated with a significantly increased risk of MI, chronic coronary insufficiency, stroke, and sudden death.6 Patients with severe obesity have substantially higher risks of diabetes mellitus and cancer.7 In a large, pooled analysis of prospective studies, both overweight and obesity were associated with increased all cause mortality in analyses restricted to participants who never smoked and did not have diagnosed cancer or heart disease.8 An analysis of Framingham data has estimated a 104% increase in the risk of developing heart failure in overweight compared to non-overweight individuals.9 A 2004 WHO report estimated that 17.1 million people worldwide die of cardiovascular disease (CVD) each year-over 29 percent of all deaths globally. By 2030, about 24 million people will die from CVDs, mainly from heart disease and stroke.10
With increasing BMI from normal to Grade III obesity, all cause mortality also increases.8 Analysis of data from the Behavioral Risk Factor Surveillance System in 2003 found that the prevalence of a BMI >40 and > 50 quadrupled (from 1 in 200 to 1 in 50, and from 1 in 2000 to 1 in 400, respectively) from 1986 to 20007, and from 2000 to 2005, both increased by another 50% and 75%, respectively.11 A recent retrospective analysis of patients undergoing echocardiography revealed a 16% and 42% increase in grade II and III obesity between 2000–2006.3
Obesity and its associated diseases have a steep price tag. An obese person is more likely to have frequent hospitalizations, and when hospitalized, a prolonged hospital course.12 Obesity is a major factor driving healthcare expenditures accounting for an estimated 12 percent of growth in recent years.13 The increased prevalence of obesity is responsible for almost $40 billion of increased medical spending through 2006. Health care attributable to overweight and obesity cost $147 billion in 2008, accounting for almost 10 percent of U.S. health expenditures.14
Our study has several important limitations, including the retrospective design and the fact that our population is limited to patients admitted with CV diagnoses in the Midwestern United States, a region of very high obesity prevalence (obesity prevalence >30%)15. Additionally, comorbidities associated with body weight were not accounted for in the analysis.
In conclusion, the prevalence of Grade II and III obesity has markedly increased among patients admitted to our hospital with major CV diagnoses from 2002 to 2009.
Figure 1.
Comparison of body mass index in patients admitted with various cardiovascular diagnoses in 2002 versus 2009.
Biography
Harshal R. Patil, MD, (above left) James H. O’Keefe, MD, (above, right), MSMA member since 2003, John House, MS, and Michael L. Main, MD, practice at Saint Luke’s Mid America Heart Institute of Kansas City. Gopi Astik, MD, is Chief Resident of Internal Medicine at the University of Missouri-Kansas City School of Medicine.
Contact: mmain@saint-lukes.org
Footnotes
Disclosures
None reported.
References
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