麻豆传媒

Expert Critique

FROM THE ASCO Reading Room

Amanda M. Sammut, MD Chief of Rheumatology New York City Health and Hospitals/Harlem

Gout attacks occur more frequently in the post-operative period. This study compared two groups of post-surgical patients, one group post-bariatric surgery and one group post non-bariatric upper abdominal surgery. The study showed that patients who were post-bariatric surgery had significantly higher rates of post-operative gout flare-ups in the first month after the surgery, compared with the non-bariatric upper abdominal surgery group (17.5% vs 1.8%). There are several possible mechanisms for why this occurs. Rapid weight loss may lead to an excess of serum lactic acid, which consequently, hinders uric acid excretion and can thus lead to a gout attack. In addition, patients who have bariatric surgery are usually placed on low carbohydrate, high protein diets, which may increase the consumption of high purine foods and thus lead to a gout attack.

Nonetheless, it is important to keep in mind the high rate of gout flares in patients who undergo bariatric surgery in order to manage them perioperatively. For instance, it is important to continue allopurinol without interruption, as otherwise a gout flare may be triggered.

Full Critique

Mystery persists around the gout flare-ups that increase shortly after bariatric surgery. However, some common -- and easily remedied -- practices could contribute to the risk.

A review published in June by the journal concluded that weight loss associated with bariatric surgery tends to ease gout symptoms and hyperuricemia, but that flare-ups are more common in the short-term after surgery.

"Weight loss seems to reduce hyperuricemia in the long-term follow-up, but there is evidence also of a high frequency of acute attacks early after surgery in patients with a diagnosis of gout," wrote study first author Claudio Tana, MD, of University Hospital of Parma in Italy, and colleagues.

A 2014 study published in investigated gout flare-ups in 99 morbidly obese patients who underwent bariatric surgery and had gout, and compared them with 56 patients who underwent non-bariatric upper abdominal procedures. Gout attacks were significantly higher in the bariatric group vs the comparison group (17.5% vs 1.8%, P=0.003) one month after surgery. There was no significant difference in the number of gout attacks in the comparison group before and after surgery (18.2% vs 11.1%, P=0.33). There was a significant reduction in uric acid levels 13 months after bariatric surgery compared with baseline values (9.1±2.0 vs 5.6±2.5 mg/dL, P=0.007).

"The frequency of early postoperative gout attacks after bariatric surgery is significantly higher than that of patients undergoing other procedures," wrote first author Hector Romero-Tamalas, MD, of Cleveland Clinic, and colleagues. "However, the incidence decreases significantly after the first postoperative month up to 1 year."

Speculation on Causes

No one is sure what causes the spike in flare-ups, but experts hypothesize that it may have something to do with changes in the body immediately following bariatric procedures as well as various clinical proclivities before and after surgery.

"Once you undergo bariatric surgery, your uric acid goes up post-op," said Hyon Choi, MD, DrPH, a rheumatologist with Harvard Medical School and Massachusetts General Hospital. "We don't understand why, but it could be related to tissue breaking down as the patient loses weight after surgery."

The 2018 narrative review observed that an increase in flare-ups is observable following any surgery, although it is higher following a bariatric procedure.

According to Tana and colleagues, hypotheses for a possible cause include the low-carbohydrate, high-protein diet that is customarily recommended to bariatric patients for two weeks before and after surgery.

Investigators noted that the Obesity Management Task Force of the European Association for the Study of Obesity recommend low carbohydrate intake combined with a protein intake of at least of 60 grams per day and up to 1.5 grams per kilogram of body weight to mitigate the loss of lean body mass following bariatric surgery. Taken together, these dietary changes are associated with an increased purine release and a ketogenic state, which impact the excretion of uric acid and ultimately increase the risk of gouty flare-ups.

Possible Solutions

As a result of this increased risk, the study authors suggested using a dietitian or nutritionist to help manage patient diets during perioperative or postoperative periods. Specifically, clinicians should consider limiting high-purine foods like red meat, certain fish including seafood and anchovies, and specific legumes like peas and lentils.

Emphasizing fluid intake, as appropriate, may also be beneficial.

"Beyond the standard dietary suggestions, a more controlled protein consumption should be indicated in these patients, and an appropriate hydration should be provided," study authors wrote.

Another key possibility lies in another non-infrequent practice -- suspension of common gout prevention drugs including allopurinol -- a practice Tana and colleagues called "erroneous."

"An erroneous discontinuation of prophylaxis drugs (e.g. allopurinol) or concomitant administration of diuretics before surgery can increase the [uric acid] levels and the risk of acute attacks and further explain this risk difference of gouty exacerbations," the authors wrote.

Experts echoed that advice, noting that patients also take it on themselves to discontinue their normal medication regimen in the perioperative period.

"We just ask them to keep taking their medicine," said Samer Mattar, MD, medical director at Swedish Weight Loss Services in Seattle.

Assuming proper precautions, there is no reason to discontinue typical gout medications prior to a bariatric procedure.

"Keep doing anything we do when we're lowering uric acid," Choi said. "Once or twice daily prophylactic based on kidney function. You could think about NSAIDs, but be careful. Just be watchful and recognize there's an increased chance."

According to experts, combining corticosteroids and NSAIDs should be avoided during perioperative or postoperative periods because of the heightened risk of gastric ulcer and upper GI bleeding. A higher-dose NSAID, or a combination of NSAIDs and colchicine, along with a proton pump inhibitor to reduce GI complication risk. Allopurinol remains the go-to option for prophylactic gout medication.

Finally, although bariatric surgery can help reduce gout symptoms in the longer term, clinicians and patients should understand that bariatric procedures are not recommended as a primary purpose of addressing gout.

"Bariatric surgery won't do for the sake of gout treatment," Choi said. "If you're seeking treatment for obesity or diabetes, gout treatment can be a side benefit [to bariatric surgery]. There's too much surgical intervention. We have many gout treatments for almost all cases if they're in the right hands."