Although metabolic benefits are often presented as one of the key benefits of bariatric surgery, in my experience, the benefits to patients in terms of less pain and mobility have always been far more impressive.
Now, a study by Wendy King and colleagues, published in JAMA, confirms these clinical observations in a large cohort of patients undergoing bariatric surgery for severe obesity.
The researchers looked at data from the Longitudinal Assessment of Bariatric Surgery, an ongoing observational cohort study at 10 US hospitals.
Based on results of 2221 participants (89% women, median BMI 46, median age 47), bariatric surgery at 1 year post surgery resulted in a clinically meaningful improvement in 60% of participants for pain, 75% for physical function, and 60% for walk time.
These improvements were largely related to significant reduction in disability related to knee and hip pain.
Nevertheless, the researchers also found that between year 1 and year 3, rates of improvement significantly decreased to 50% for pain and to 70% for physical function, although improvement rates for walk time, knee and hip pain, and knee and hip function were largely sustained.
Variables that appeared to increase the chances of post-surgical benefits included younger age, male sex, higher income, lower BMI, and fewer depressive symptoms presurgery; no diabetes and no venous edema with ulcerations postsurgery (either no history or remission); and presurgery-to-postsurgery reductions in weight and depressive symptoms.
Given that (in contrast to metabolic problems) there are few effective medical treatments for pain and mobility, these “benefits” of bariatric surgery certainly warrant greater attention as it is often these (and not the metabolic problems) that determine the often poor quality of life associated with severe obesity.
Regular readers, however, will perhaps previous posts on this issue, suggesting that BMI is largely irrelevant in terms of outcomes and benefits for obese patients requiring knee replacements.
This previous finding is further supported by a new paper by David Murray and colleagues from The University of Oxford, UK, published in KNEE.
The researchers prospectively examined the impact of BMI on failure rate and clinical outcomes of 2,438 unicompartmental knee replacements in 378 patients with a BMI less than 25, 856 patients with a BMI 25 to 30, 712 patients with a BMI 30 to 35, 286 patients with a BMI 35 to 40, 126 patients with a BMI 40 to 45 and 80 patients with BMI greater than 45.
At a mean follow-up of 5 years (range 1–12 years) there was no significant difference in the Objective American Knee Society Score between BMI groups.
Although there was a slight trend to decreasing post-operative function scores with increasing BMI, patients with higher BMI had lower scores prior to surgery. Thus, overall higher BMIs were associated with a greater change in functional scores.
Thus, this study, further confirms the notion that obese individual have as much (if not more) to benefit from knee replacement surgery with little evidence that initial BMI adversely affects outcomes.
For clinicians this finding means that there is little evidence to deny knee replacement surgery to individuals with higher BMI levels or require that these patients lose weight prior to surgery.
If you have experience (positive or negative) with knee replacement surgery in overweight and obese patients, I’d like to hear from you.
Just how closely obesity and pain are associated is now documented by Arthur Stone and Joan Broderick from Stony Brook University, NY, in a paper just published in OBESITY.
This study is based on a Gallup ‘poll’ of 1,062,271 randomly selected US individuals surveyed between 2008 through 2010.
BMI and pain yesterday were reliably associated (even when adjusted for a wide range of demographic variables): the overweight group reported 20% higher rates of pain than Low-Normal group, 68% higher for Obese I group, 136% higher for Obese II group, and 254% higher for Obese III group.
All of the tests of association between the pain conditions and BMI groups were significant, with the strongest association for the knee and leg condition.
The association held for both men and women but in women, the trend to more pain as BMI increases was steeper than in men.
The association between BMI and pain increases moving from the younger categories to the older categories; for those in the Obese III group, the odds ratio for the youngest group is 1.72 compared with a ratio of 3.79 for those in the highest age group.
As the authors note,
“The association is robust and holds after controlling for several pain conditions and across gender and age. The increasing BMI-pain association with older ages suggests a developmental process that, along with metabolic hypotheses, calls out for investigation.”
Despite the possible limitations due to the nature of the survey (telephone, self-reported height and weight and pain levels, etc.), the relationship between higher weight and pain is striking.
Assessing for pain (the 2nd ‘M’ or ‘Mechanical’) should be routine part of any exam for obesity and may have to be tackled in any obesity management program.
Stone AA, & Broderick JE (2012). Obesity and pain are associated in the United States. Obesity (Silver Spring, Md.), 20 (7), 1491-5 PMID: 22262163
Osteoarthritis in hips and knees is a common progressive disease leading to joint pain and severe disability. It is a complex multifactorial condition leading to damage of cartilage, deposition of subchondral bone matrix and release of pro-inflammatory cytokines.
One of the most common risk factors for osteoarthritis is carrying around excess weight. In fact, no matter what the root cause of the problem (trauma or otherwise), weight loss has consistently been shown to reduce pain (for e.g. each lb lost takes about four pounds off each knee).
So the question arises, whether bariatric surgery should be used more commonly in obese patients with osteoarthritis in hips or knees.
In a paper authored by Richdeep Gill and other colleagues, just published in Obesity Reviews, we report our findings from a systematic review of the literature on bariatric surgery and osteorarthritis.
A comprehensive search of electronic databases using broad search terms revealed a total of 400 articles, including six studies, which met our criteria for inclusion in our qualitative analysis.
Although there was a clear trend towards improvement of hip and knee osteoarthritis in hips and knees following bariatric surgery, the data consists largely of case series.
Thus, it may well be time to conduct a large randomized controlled trial to determine whether or not bariatric surgery should perhaps be routinely considered as a means to better manage hip or knee osteoarthritis in patients with severe obesity.
Gill RS, Al-Adra DP, Shi X, Sharma AM, Birch DW, & Karmali S (2011). The benefits of bariatric surgery in obese patients with hip and knee osteoarthritis: a systematic review. Obesity reviews : an official journal of the International Association for the Study of Obesity PMID: 21883871
A study by Ian Janssen and colleagues from Queen’s University, Kingston, Ontario, published in the Journal of Obesity, examines the relationship between occupational injury and obesity in the canadian workforce.
These authors have previously described a biophysical framework on the possible determinants of increased risk in obese individuals:
“… obesity is associated with (1) a number of risk factors for unintentional injury (increased comorbidities, increased use of psychotropic medications, altered gait and balance, increased forces involved in falls, lower neural sensitivity, greater extremity friction, and sleep apnea and fatigue) as well as (2) some protective factors that will help prevent injury (greater bone density and increased cushioning during falls from excess fat).”
In their analysis of data in a representative longitudinal sample of 7,678 adult Canadian workers obese workers were about 40% more likely to report any occupational injuries and almost 50% more likely to report serious occupational injuries than normal-weight workers.
These relationships were more pronounced for sprains and strains (80% higher risk), injuries to the lower limbs (2-fold higher risk) or torso (almost 2.5-fold higher risk), and injuries due to falls (2-fold) or overexertion (2-fold).
Female workers, workers ≥40 years, and workers employed in sedentary occupations were particularly vulnerable.
Importantly, while this association was found for obese individuals, risk for overweight workers was not increased.
Nevertheless, regarding population attributable risk (PAR), the authors point out that:
“If the relationships under study are accurate and causal in nature, the PAR estimates indicate that approximately one in ten occupational injury events in the Canadian workforce are directly attributable to obesity, with up to one in five occupational injuries being attributable to obesity in susceptible population subgroups.”
Thus, the authors have the following suggestions for employers:
“…employers should consider how obesity impacts and interacts with other salient and modifiable risk factors for workplace injury such as job and task design, physical environments, and social factors. For example, workstations can be designed to be ergonomically sound for heavier persons and not just the average person.
“…employers should consider adopting or expanding workplace wellness initiatives aimed at improving physical activity and eating behaviours in their workforce.”
The authors also note that:
“Although the medical services associated with workplace injury in Canada are covered by our public health care system and not the employer or its insurance provider, employers need to recognize that investments into workplace wellness initiatives could still have a favourable impact on the bottom line by reducing absenteeism and lost productivity.”
Is your workplace ‘safe’ for obese employees? How can it be made safer?
All suggestions are appreciated.
Janssen I, Bacon E, & Pickett W (2011). Obesity and its relationship with occupational injury in the canadian workforce. Journal of obesity, 2011 PMID: 21773008