Bariatric treatments for adult obesity - Institute of Health Economics

Another study also reported that, when compared to the weight-stable group, weight loss wasdetrimental for non-cancer mortality. However, the intentionality of weight loss was not reported.The third study conducted an analysis on overweight men and adjusted for several variables tocontrol for demographic variations and the probably of underlying diseases. This study showed thatmortality risk improved in the intentional weight loss group as compared to the weight-stablesubgroup; however there was no difference for those with comorbidities or who lost weightunintentionally.Overall, the impact of weight loss on mortality in men is not clear. A meta-analysis of all the studiesusing a random effect model demonstrated that, as compared to the reference group of overweightbut weight-stable men, the overall effective weight loss was shown to be slightly detrimental. Whenstudies with the outcome of intentional weight loss were combined using a fixed effect model, thehazard ratio became non-significant.Results for women and men combinedThree studies—one conducted in the United States, one in Canada, and one in Finland—examinedthe impact of weight loss on mortality risk in overweight or obese men and women. All three studiesreported mortality for a similar time period, from the mid 1980s to the beginning of the newmillennium. The participants in the US study were about a decade older than those in the otherstudies, hence the average age varied slightly between the studies.The US study adjusted their analysis for more than 13 variables and also attempted to account forknown underlying diseases. For those who claimed to be trying to lose weight, the effects weremarginally beneficial if they remained weight-stable or lost small amounts of weight. In contrast, theFinnish study found that for those with intentional weight loss, the effect of weight loss wasdetrimental. A meta-analysis of these two studies indicated no significant difference between thegroups.The Canadian study examined the impact of bariatric surgery on mortality in morbidly obesepatients. Of the 1035 patients who received surgery, seven patients (0.7%) died as compared tothose under standard treatment, where 354 of 5746 patients (6.2%) died. Usually surgery is onlyconsidered for those to whom obesity is life-threatening. Consequently, the surgical group does havea substantially reduced mortality risk as compared to a comparable control group who did notundergo surgery. Similarly, the effects of the surgery are difficult to disentangle from any weight lossbenefits for this subgroup.Factors that may have an impact on the outcomesGender differences, the presence of comorbidities, and the notion of intentionality of weight losshave been identified as important factors that may have impacted outcomes. With respect to gender,for studies with men only and with men and women combined, the effects of weight loss onmortality were inconsistent regardless of intentionality. On the other hand, one study demonstratedbenefits from weight loss in overweight or obese women with pre-existing comorbidities. However,patients with diabetes, regardless of gender, benefited from intentional weight loss.Methodological limitationsBenefits of weight loss on all-cause mortality for overweight or obese patients are meager. The mostimportant explanations are intentionality, self-reporting of weight loss, and the time lapse betweenthe last recorded weight loss measurement and the mortality outcome.Bariatric treatments for adult obesity 89