Review Article

The Obesity Paradox and Heart Failure: A Systematic Review of a Decade of Evidence

Table 2

Study characteristics and results.

Author Country Design Sample
size
Follow-up time Median/mean age Weight
status
measure
Self-report/measuredOutcome parameterResultsQualityLimitations

Zamora et al. (2013) [47] Spain Prospective cohort 504 6.1 years
(IQR 2.2–7.8)
68 years
(IQR 58–74)
BMI Measured Hazard ratio Lower risk of death associated with obesity.
Hazard ratios were 2.08
(1.16–3.75), 0.88 (0.54–1.43), and 0.49 (0.28–0.86) for underweight, overweight, and obese patients, respectively.
Strong

Casas-Vara et al. (2012) [42] Spain Prospective cohort 244 984 days
(2.7 years)
(83.2 ± 0.5) BMI Measured Survival Overall median survival was
984 days with better survival as BMI increased; log ranks were 5.26, 8.45, and 10.95 for underweight, overweight, and obese patients, respectively.
Moderate Baseline characteristics of study population were not fully reported.

Lavie et al. (2013) [43] USA Prospective cohort 2066 5 years
(25.0 ± 17.5 months)
BMI Measured 5-year survival Overall better prognosis in patients with higher BMI. On stratification on high FIT versus low FIT, obesity paradox persists in the high fit group but not in the low fit group. Moderate Primary objective was comparison between low fit versus high fit and not obese versus lean.

Gastelurrutia et al. (2011) [44] Spain Prospective cohort 979 44 months 65 ± 12 years BMI Measured Hazard ratio Lower risk of death associated with higher BMI when compared to normal BMI = 0.94, (0.91–0.97). Strong

Clark et al. (2011) [36] USA Retrospective cohort344 2 years 53.3 ± 13.1 years BMI, WC Measured 2-year survival Higher 2-year survival in high versus normal WC: 77.9% versus 64.3%, and high versus normal
BMI: 89.8% versus 58.2%.
ModerateRetrospective analysis of data of patients seen at a specialist center for heart transplant patients selected based on disease severity and prognosis and thus not likely to be representative of all heart failure patients.

Clark et al. (2012) [35] USA Retrospective cohort 2718 2 years 53.0 ± 12.4 years BMI, WC Measured 2-year survival Higher 2-year survival with increasing BMI in both sexes. Men: high versus normal, BMI (63.2% versus 53.5%), WC (78.8% versus 63.1), women: BMI (67.1% versus 56.6%), WC, no difference. Moderate Not many women were included (~25%), bringing into question the power to detect differences in that subgroup.

Schwartzenberg et al. (2012) [48] Israel Prospective cohort 2323 15 months 71.6 ± 12.5 yearsBMI Not stated Hazard ratio Lower risk of death in persons with higher BMI. Normal versus higher BMI, though not statistically significant after adjustment. Hazard ratio of 0.79 (95% CI 0.59–1.05). Moderate Important baseline
characteristics not shown.

Kapoor and Heidenreich (2010) [49] USA Retrospective cohort 1236 426 ± 461 days 71 ± 12 years BMI Measured Hazard ratio Lower risk of death as BMI increased until BMI > 45.
Hazard ratios were 1.68 (95% CI, 1.04–2.69), 0.99 (95% CI,
0.71–1.36), 0.58 (95% CI, 0.35–0.97), 0.79 (95% CI, 0.44–1.4), and 1.38 (95% CI 0.74–2.6) for underweight, overweight, obese, and morbidly obese patients and BMI > 45 kg/m2, respectively. Thus, underweight and BMI > 45 kg/m2 were associated with increased risk of death.
Strong

Curtis et al. (2005) [45] USA Clinical trial 7767 37 months 63.9 ± 10.9 yearsBMI Measured Hazard ratio Lower risk of death associated with increasing BMI. Using normal BMI as reference, hazard ratios were
1.21 (0.95–1.53), 0.88 (0.80–0.96), and 0.81 (0.72–0.92) for underweight, overweight, and obese patients, respectively.
ModerateResults were primarily for a Digitalis clinical trial; thus, results were reanalyzed with a new hypothesis that was specified after study.

Zuchinali et al. (2013) [46]Brazil Prospective cohort 344 30 ± 8.2 months 59 ± 13 TSF Measured Hazard ratio TSF > 20 mm was a strong predictor of all-cause
mortality. Hazard ratio = 0.36
(0.13–0.97, ).
Results for other measures of body fat composition, BMI, WC, arm circumference (AC), Arm Muscle Circumference (AMC), and TSF, were not statistically significant in any direction.
Strong