Fitness is important for patients undergoing obesity surgery according to a recent study by McCullough et al.
In a prospective study, Dr. McCullough and colleagues divided 108 patients into different groups based on their cardio respiratory (aerobic) fitness as determined by peak oxygen (O2) levels during exercise testing.
Average peak O2 for the three groups was:
The average age of the patients was 46. Eighty-two (75.2%) were women. The average BMI was 48.7 (range 36 to 90 kg/m2). Patients in Group 1 were more likely to be female, older, and nonwhite, and had a higher BMI, and had diabetes and hypertension. Rates of coronary heart disease, lung diseases and arthritis were similar among the three groups. Of note, six of 37 patients (16.2%) in Group 1 were cigarette smokers, compared with three of 72 patients (4.2%) of Groups 2 and 3 combined.
Operative times were longer by 24.8 minutes for Group 1 compared with Group 3. Hospital length of stay and 30-day readmission rates (assessed in all patients) were highest in Group 1 (3.8 days, vs 2.8 days for all others).
Overall, the investigators found that patients in Group 1 were nearly six times more likely to suffer primary complications -- death, heart attack, venous thrombosis, pulmonary embolus, kidney failure, or stroke -- than those in Groups 2 & 3 combined. Specifically, 6 (16.6%) of the 37 patients in Group 1 suffered one or more major complications compared with only two (2.8%) in the other two groups.
The authors conclude that physicians should measure cardiopulmonary fitness before operating since this is an important predictor of outcomes. Nevertheless, obesity surgery is still an extremely powerful intervention in those for whom other alternatives have failed. "The benefits of bariatric surgery clearly outweigh the risks" said Dr. McCullough. "Morbid obesity is associated with numerous health risks, including cardiovascular disease, respiratory conditions, diabetes, sleep apnea, and an increased rate of death (and) bariatric surgery has been shown to reduce co-morbidities and long-term mortality in morbidly obese patients."
Comment
The main limitation of this study (as the authors themselves concede) is the relatively small sample size. Moreover, the observation that patients with low levels of fitness are likely to be more at risk during surgery, hardly seems counter-intuitive. Patients with low aerobic capacity will have less respiratory reserve and a greater probability of underlying coronary heart disease. Whilst the investigators recommend exercise testing prior to surgery would be advantageous, it is difficult to see what this would add to the practical management of the patient. Any team providing a bariatric service would assume that every patient has a low cardio-respiratory reserve and plan accordingly.
McCullough PA et al. "Cardiorespiratory Fitness and Short-term Complications after Bariatric Surgery." Chest 2006; 130:517-525.
