LAS VEGAS — One of the first studies to look at the effect of weight loss on ambulatory care costs has found a puzzling yo-yo pattern, Gregory A. Nichols, Ph.D., said at the annual meeting of the North American Association for the Study of Obesity.
Medical costs decreased an average of $350 per person for 458 Kaiser Permanente health plan members during the first enrollment year after they lost at least 5% of their body weight in the plan's voluntary Freedom From Diets program. However, these costs started to rebound 3-4 years later, driven up in large part by the health care needs of the patients who maintained their weight loss.
“There could be some explanation, but clearly we need to do a lot more work,” said Dr. Nichols, a senior research associate at Kaiser Permanente's Center for Health Research in Portland, Ore. The effect, he acknowledged, seems counterintuitive.
The study did find an economic advantage for Kaiser. Costs went up an average of $480 in the first enrollment year for the 547 patients who did not lose weight in the program. The net difference, $830, was statistically significant, he said.
Another conundrum, however, was that a control group of 2,290 Kaiser Permanente members who did not enroll in the program and did not lose weight had consistently lower costs than did the Freedom From Diets participants. The control group was matched for age, gender, and body mass index (BMI) of 35 kg/m
Dr. Nichols' study was supported by a grant from GlaxoSmithKline.
Audience members speculated that people who were enrolled in a voluntary program might be more inclined to incur health care costs than would those who were not. Another possible explanation, Dr. Nichols said, was that those who signed up for the weight loss program might have been more motivated because they had comorbidities.
In another presentation of Kaiser Permanente research, Jonathan Betz Brown, Ph.D., a senior investigator with Nichols, found that pharmaceutical savings were the only cost efficiency for 67 patients.
Reduced use of antidiabetic, antihyperglycemic, antihypertensive, and gastrointestinal drugs resulted in a $510 savings. Pharmaceutical costs went up $393 for candidates who did not have bariatric surgery, and $432 for general members of the health plan. Total medical costs for the bariatric patients rose, however, from $5,359 the year before surgery to $5,705 the year after and $6,013 2 years later.
Dr. Brown said the study might have been too short and too small to find a cost benefit so soon after an expensive procedure. The operation costs $29,824 on average, he said.