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Weight and Weight Change—Think About the Context

      SEE RELATED ARTICLES p. 924 and 931
      While obesity has been linked to multiple risk factors for cardiovascular disease and risk for type 2 diabetes and its complications, several epidemiologic studies have suggested that patients with excess weight may not have higher rates of (cardiovascular) mortality. Two articles in this issue of The American Journal of Medicine and one in the September issue demonstrate how the question of an “obesity paradox” can be very tricky to answer.
      The study by Waring et al
      • Waring M.E.
      • Saczynski J.S.
      • McManus D.
      • et al.
      Weight and mortality following heart failure hospitalization among diabetic patients.
      raises a question as to whether “all weight is created equal.” Patients from central Massachusetts had their weight measured on admission when they almost certainly had excess extracellular water from heart failure. The measure of their admission weight (water+fat) would not accurately reflect their total fat mass (or necessarily predict their future risk). Additional sources of admission weight (either water or fat) could have resulted from medications (eg, thiazolidinediones) which might have changed over time. Weight change over time was not collected in the Worcester study. Studies—especially those in heart failure—may benefit from distinguishing relative contributions of water and fat (and underlying medications).
      The second issue is whether “all weight change is created equal.” The paradox reported by Myers et al
      • Myers J.
      • Lata K.
      • Chowdhury S.
      • McAuley P.
      • Jain N.
      • Froelicher V.
      The obesity paradox and weight loss.
      was not really about obesity; the study compared those who gained versus those who lost weight among Veterans Administration (VA) subjects referred for exercise testing. The results were less about those who gained weight doing well and more about those who lost weight doing poorly. As clinicians, we have all seen examples of patients who lose weight in ways or patterns that arouse concern. Within the reported data, over half of the subjects in the weight loss group died from conditions such as HIV/AIDS, hepatitis/cirrhosis, renal failure, cancer and heart failure.
      Nonetheless, for those at the severe end of the obesity spectrum (body mass index=40-60 kg/m2), weight loss seems to be helpful. The study by Johnson et al,
      • Johnson W.D.
      • Brashear M.M.
      • Gupta A.K.
      • Rood J.C.
      • Ryan D.H.
      Incremental weight loss improves cardiometabolic risk in extremely obese adults.
      demonstrated in a prospective fashion that losing weight was associated with improvement in nearly all cardiometabolic risk factors. This type of intentional weight loss would yield praise much more than concern from most clinicians.
      But if weight loss is not always good, then is all weight gain bad? Within the group of VA patients who gained weight, conditions of stroke, heart failure, diabetes and pulmonary disease were more common among those who died than survived. These findings do not seem very paradoxical. And yet perhaps there are times when weight gain is not all bad. These may be the circumstances to watch for.
      If patients who have or develop poorly-controlled diabetes improve glucose levels with insulin (especially if used in combination with thiazolidinediones), weight gain would be expected as part of improved control. This is not a comment on whether “tight” control was responsible or whether a particular class of medications is preferable. It is a comment that medical regimens for poorly controlled diabetes could include agents which improve overall survival at the cost of gaining weight. There may be other medications (eg, glucocorticoids, psychiatric) which improve health while promoting weight gain. Perhaps some of these factors explain the lack of negative consequences for patients who gained weight while participating in the Louisiana program reported by Johnson et al. In the primary care setting of this study, a lack of weight loss might have prompted increases in medications aimed at glucose, systolic blood pressure or triglycerides/HDL.
      Other factors may explain a lack of adverse events related to weight. Perhaps a bias for referring obese individuals caused those with less overall disease burden to be referred more readily for exercise tests in the VA system (or to be admitted from Emergency Departments in Massachusetts) than their lower weight counterparts. Another possibility is that there are some individuals who can tolerate weight with a minimum of negative sequelae. A subgroup of those who are “fit but fat”
      • Fogelholm M.
      Physical activity, fitness and fatness: relations to mortality, morbidity and disease risk factors A systematic review.
      could make it more difficult to prove generalized negative consequences of obesity. In the VA study, lower exercise capacity was associated with increased risk of death in both the weight loss and weight gain groups. Exercise was not a component of the weight loss program for the LOSS study. Perhaps future goals need to emphasize fitness as much as (or more than) weight.
      • Sui X.
      • LaMonte M.J.
      • Laditka J.N.
      • et al.
      Cardiorespiratory fitness and adiposity as mortality predictors in older adults.
      Ultimately, even if mortality rates are not worse for obese patients or those who gain weight, morbidity might be. While mortality is clearly an important endpoint, it may not be the only endpoint. If patients with weight gain are less likely to die but more likely to suffer with musculoskeletal abnormalities, severe sleep apnea, foot amputations, vision impairment, dialysis, malignancy or other weight-related consequences then we still have a serious set of public health problems which cannot be dismissed as a paradox.

      References

        • Waring M.E.
        • Saczynski J.S.
        • McManus D.
        • et al.
        Weight and mortality following heart failure hospitalization among diabetic patients.
        Am J Med. 2011; 124: 868-874
        • Myers J.
        • Lata K.
        • Chowdhury S.
        • McAuley P.
        • Jain N.
        • Froelicher V.
        The obesity paradox and weight loss.
        Am J Med. 2011; 124: 924-930
        • Johnson W.D.
        • Brashear M.M.
        • Gupta A.K.
        • Rood J.C.
        • Ryan D.H.
        Incremental weight loss improves cardiometabolic risk in extremely obese adults.
        Am J Med. 2011; 124: 931-938
        • Fogelholm M.
        Physical activity, fitness and fatness: relations to mortality, morbidity and disease risk factors.
        Obes Rev. 2010; 11: 202-221
        • Sui X.
        • LaMonte M.J.
        • Laditka J.N.
        • et al.
        Cardiorespiratory fitness and adiposity as mortality predictors in older adults.
        JAMA. 2007; 298: 2507-2516