Baseline Obesity and Subsequent Weight Loss Are Independently Associated with Cardiovascular Mortality in Established Rheumatoid Arthritis

Bryant R. England¹, Joshua F. Baker², Harlan Sayles³, Kaleb Michaud^4,5, Liron Caplan⁶, Lisa A. Davis⁶, Grant W. Cannon⁷, Brian Sauer⁸, E. Blair Solow⁹, Andreas Reimold¹⁰, Gail S. Kerr¹¹, Pascale Schwab¹² and Ted R. Mikuls¹³, ¹Division of Rheumatology, Department of Internal Medicine, University of Nebraska Medical Center, Omaha, NE, ²Rheumatology, University of Pennsylvania, Philadelphia, PA, ³University of Nebraska Medical Center, Omaha, NE, ⁴Internal Medicine, Division of Rheumatology, University of Nebraska Medical Center, Omaha, NE, ⁵National Data Bank for Rheumatic Diseases, Wichita, KS, ⁶Div of Rheumatology, Univ of CO Denver School of Med, Aurora, CO, ⁷Division of Rheumatology, Salt Lake City VA Medical Center and University of Utah, Salt Lake City, UT, ⁸Salt Lake City VA Medical Center and University of Utah, Salt Lake City, UT, ⁹Rheumatology, UT Southwestern Medical Center, Dallas, TX, ¹⁰Rheumatology, VAMC, University of Texas Southwestern Medical Center, Dallas, TX, ¹¹VAMC, Georgetown University, Washington, DC, ¹²Div Arth & Rheum Dis, Oregon Health & Sci Univ OP09, Portland, OR, ¹³Medicine, University of Nebraska Medical Center, Omaha, NE

Meeting: 2015 ACR/ARHP Annual Meeting

Date of first publication: September 29, 2015

Keywords: Cardiovascular disease, death, obesity, rheumatoid arthritis (RA) and weight loss

Session Information

Date: Sunday, November 8, 2015

Title: Epidemiology and Public Health Poster I: Comorbidities and Outcomes of Systemic Inflammatory Diseases

Session Type: ACR Poster Session A

Session Time: 9:00AM-11:00AM

Background/Purpose: In the general population, higher body mass index (BMI) is associated with cardiovascular (CV) disease. However, an obesity paradox has been observed in rheumatoid arthritis (RA), where lower BMI is associated with adverse outcomes while obesity appears to be protective. This relationship may be confounded by weight-loss among sicker individuals. We sought to comprehensively examine independent associations between baseline BMI and recent weight loss with CV mortality in RA.

Methods: Patients in the Veterans Affairs RA Registry were followed from enrollment until death or December 2013. BMI was obtained from medical records ±14 days of each visit. Enrollment BMI was categorized as underweight (<22 kg/m²), normal (22-25 kg/m²), overweight (25-30 kg/m²) and obese (>30 kg/m²). An annualized rate of BMI change was determined from the slope of BMI over time from visits in the preceding 13 months (categories: <0, 0-2, 2-3, and >3 kg/m² lost/year). Vital status and cause of death were determined through the National Death Index. Associations with CV mortality were examined using multivariable competing-risks regression.

Results: There were 1,652 patients with 99 CV deaths occurring over 5,851 patient-years of follow-up. Patients were predominantly male (91%), had established disease (mean 11.7±11.4 years), and were positive for RF (80%) or anti-CCP antibody (78%). Mean BMI at enrollment was 28.6±5.7 kg/m² with 9% underweight, 18% normal, 38% overweight, and 35% obese. Associations with CV mortality are shown in Table 1. In age- and gender-adjusted models (Model A), enrollment BMI category was not associated with CV mortality. In a multivariable model adjusting for comorbid conditions (Model B), an obese BMI at enrollment was associated with greater CV mortality (Hazard ratio [HR] 1.55, 95% confidence interval [CI] 1.05-2.27, P = 0.026). Annualized recent weight loss of more than 3 kg/m²/year was also independently associated with CV mortality (HR 1.66, 95% CI 1.24-2.22, P = 0.001). Cumulative incidence of CV death by weight loss categories is shown in Figure 1.

Conclusion: Obesity at enrollment and greater rates of weight loss are independently associated with CV mortality in RA. These results suggest that weight loss rather than low body weight per se may drive the observed Òobesity paradoxÓ in RA with regard to CV risk. Preventive strategies for CV mortality in RA should focus on maintaining a normal BMI.

Table 1. Association of Body Mass Index and Weight Loss with Cardiovascular Mortality
Variables	Model A	Model B	Model C
	N=1652	N=1383	N=1379
Enrollment BMI category
Underweight	1.45 (0.78-2.70)	1.43 (0.55-3.72)	1.43 (0.54-3.82)
Normal	1.00	1.00	1.00
Overweight	1.24 (0.93-1.66)	1.46 (0.63-3.42)	1.42 (0.62-3.24)
Obese	1.23 (0.78-1.94)	1.55 (1.05-2.27)*	1.47 (1.01-2.12)
Weight loss category
No loss or gain	–	–	1.00
<2 kg/m²	–	–	1.02 (0.73-1.44)
2-3 kg/m²	–	–	1.14 (0.60-2.18)
>3 kg/m²	–	–	1.66 (1.24-2.22)ǂ
* P = 0.026; P = 0.047; ǂ P = 0.001 Abbreviations: BMI, body mass index. Model A covariates include age and gender. Model B & C covariates include age, gender, race, smoking status, Rheumatic Disease Comorbidity Index score, prior myocardial infarction, and prior other cardiovascular disease.

Figure 1. Cumulative Incidence of Cardiovascular Mortality by Weight Loss Category in Rheumatoid Arthritis.

*Weight loss category modeled as time varying variable

Disclosure: B. R. England, None; J. F. Baker, None; H. Sayles, None; K. Michaud, None; L. Caplan, None; L. A. Davis, None; G. W. Cannon, Amgen, 2; B. Sauer, None; E. B. Solow, None; A. Reimold, None; G. S. Kerr, None; P. Schwab, None; T. R. Mikuls, None.

To cite this abstract in AMA style:

England BR, Baker JF, Sayles H, Michaud K, Caplan L, Davis LA, Cannon GW, Sauer B, Solow EB, Reimold A, Kerr GS, Schwab P, Mikuls TR. Baseline Obesity and Subsequent Weight Loss Are Independently Associated with Cardiovascular Mortality in Established Rheumatoid Arthritis [abstract]. Arthritis Rheumatol. 2015; 67 (suppl 10). https://acrabstracts.org/abstract/baseline-obesity-and-subsequent-weight-loss-are-independently-associated-with-cardiovascular-mortality-in-established-rheumatoid-arthritis/. Accessed .

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