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T2DM and surgery

Type 2 diabetics should be prioritised for surgery

Credit: Alden Chadwick/Flickr
The researchers found that drug costs did not differ between the surgery and conventional treatment groups in the euglycaemic subgroup
They reported no difference between treatment groups in patients with diabetes

When considering overall costs of healthcare, obese patients with type 2 diabetes and especially those with recent disease onset, should be prioritised for bariatric surgery over those without type 2 diabetes since many patients see a reversal of diabetes after surgery and thus need fewer expensive diabetes medications or treatment for complications in future. These are claims made by Swedish and Australian researchers in their paper, ‘Health-care costs over 15 years after bariatric surgery for patients with different baseline glucose status: results from the Swedish Obese Subjects study’, published in The Lancet Diabetes & Endocrinology.

The research is based on the Swedish Obese Subjects (SOS) study from Sahlgrenska Academy, Gothenburg, Sweden, and performed in collaboration with Dr Martin Neovius, Karolinska Institutet, Stockholm, Sweden, Dr Lena Carlsson, Chief SOS Investigator, University of Gothenburg, Sweden, and Dr Catherine Keating, Deakin University and Baker IDI Heart and Diabetes Institute, Melbourne, Australia.

“Bariatric surgery should be held to the same economic standards as other medical interventions."

Currently most healthcare systems prioritise access to obesity surgery based on a person's BMI and in general, those with the highest BMI are prioritised. Patients with lower BMIs and comorbidities such as T2DM can also be considered eligible for surgery, but different countries have different guidelines. Several groups have recommended that a person's diabetes status (rather than BMI alone), be used to prioritise obese patients to receive bariatric surgery. But so far, the long-term effect of bariatric surgery (relative to conventional therapy) on healthcare costs in obese patients according to their diabetes status has not been assessed using real-world data. Therefore, the authors sought to assess healthcare costs over 15 years for patients with obesity treated conventionally or with bariatric surgery and who had either euglycaemia, prediabetes, or T2DM before intervention.

The Swedish Obese Subjects (SOS) study is a prospective study of adults who had bariatric surgery (2,010) and contemporaneously matched controls (2,037) who were treated conventionally (age 37–60 years; BMI≥34 in men and ≥38 in women) recruited from 25 Swedish surgical departments and 480 primary health-care centres.

The researchers retrieved prescription drug costs for the patients in the SOS study via questionnaires and the nationwide Swedish Prescribed Drug Register, as well as retrieved data for inpatient and outpatient visits from the Swedish National Patient Register. They followed up the sample linked to register data for up to 15 years and adjusted mean differences for baseline characteristics, with the analyses by intention to treat.


In total, 4,030 patients (2,836 who were euglycaemic; 591 who had prediabetes; 603 who had diabetes) were followed. The researchers found that drug costs did not differ between the surgery and conventional treatment groups in the euglycaemic subgroup (surgery US$10,511 vs conventional treatment US$10,680; adjusted mean difference –$225 [95% CI −2080 to 1631]; p=0.812), but were lower in the surgery group in the prediabetes ($10,194 vs $13,186; –$3329 [–5722 to −937]; p=0.007) and diabetes ($14,346 vs $19,511; –$5487 [–7925 to −3049]; p<0,0001) subgroups than in the conventional treatment group.

Compared with the conventional treatment group, they noted greater inpatient costs in the surgery group for the euglycaemic ($51,225 vs $25,313; $22 931 [19 001–26 861]; p<0.0001), prediabetes ($58,699 vs $32,861; $27,152 [18 736–35 568]; p<0.0001), and diabetes ($61,569 vs $47,569; 18 697 [9992–27 402]; p<0.0001) subgroups. They found no differences in outpatient costs. This is probably because the remission of diabetes that often occurs after bariatric surgery means that patients need fewer diabetes medications and hospital appointments in the subsequent years. Remission of diabetes also means that diabetes complications are lessened, further reducing future healthcare costs.

The total health-care costs were higher in the surgery group in the euglycaemic ($71,059 vs $45,542; $22,390 [17 358–27 423]; p<0.0001) and prediabetes ($78,151 vs $54,864; $26,292 [16 738–35 845]; p<0.0001) subgroups than in the conventional treatment group, whereas they reported no difference between treatment groups in patients with diabetes ($88,572 vs $79,967; $9,081 [–1419 to 19 581]; p=0.090).

Because previous studies have assessed the entire eligible obese population, they have likely underestimated the cost benefits of bariatric surgery for those with type 2 diabetes, while overestimating them for patients without type 2 diabetes, the authors state.

“We show that for obese patients with type 2 diabetes, the upfront costs of bariatric surgery seem to be largely offset by prevention of future health-care and drug use. This finding of cost neutrality is seldom noted for health-care interventions, nor is it a requirement of funding in most settings,l” they conclude. “Usually, buying of health benefits at an acceptable cost (eg, £20 000 per quality-adjusted lifeyear in the UK) is the economic benchmark adopted by payers when new interventions are assessed. Bariatric surgery should be held to the same economic standards as other medical interventions."

In a link comment paper, ‘Bariatric surgery: time to move beyond clinical outcomes’, also published in the journal, Dr Ricardo Cohen, Director of the Center of Excellence for Metabolic and Bariatric Surgery, Hospital Oswaldo Cruz, São Paulo, Brazil, writes: "This finding lends support to the notion that this expenditure is therefore not related to BMI or the amount of postoperative weight loss. In patients with obesity and either euglycaemia or prediabetes at baseline, total health-care costs after up to 15 years follow-up were greater in patients who underwent bariatric surgery than in those treated conventionally…BMI should...not be the only indication for bariatric surgery. Thus, individuals that do not have their diabetes under control with the best pharmacological approach and lifestyle interventions should be prioritised for bariatric surgery, irrespective of their BMI."

This study was funded by AFA Försäkring and Swedish Scientific Research Council. 

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