Endocrine Abstracts

Background: Bariatric surgery is known to dramatically increase insulin sensitivity in severely obese adults. However quantifying insulin sensitivity in these patients with methods such as the hyperinsulinaemic euglycaemic clamp is technically challenging. The leptin to adiponectin ratio (LAR) has previously been validated as a measure of whole body insulin sensitivity. Leptin is a known mediator of metabolic and cardiovascular complications of obesity. Adiponectin has anti-atherogenic, antidiabetic, and anti-inflammatory properties. The influence of bariatric surgery on LAR has not previously been described.

Aim and objectives: We sought to determine changes in LAR over 12 months in severely obese adults undergoing sleeve gastrectomy.

Methods: We conducted a single-centre, prospective cohort study of all patients undergoing sleeve gastrectomy between September and December 2016. Anthropometric data, metabolic profiles, leptin and adiponectin levels were collected before and one year after surgery. Leptin and adiponectin were both measured using the two-site micro titre plate-based DELFIA assay. Data are presented as means ± standard deviation. Comparisons between baseline and follow up measures were performed using a paired T-test.

Results: Twenty-five patients underwent surgery, and 17 of these (12 female, 9 with diabetes mellitus (DM) (defined as baseline HbA1c≥48 mmol/mol)) attended for follow up at 12 months and were included in analyses. Mean age was 52.2±8.3 (range 39–71) years. Mean follow up interval was 12±1 (range 10–13) months. Weight reduced from 130.5±30.8 kg to 97.5±21.6 kg (P<0.001), BMI from 46.8±7.8 to 35.3±7.2 kgm⁻² (P<0.001), excess body weight percentage from 87.5±31.2 to 41.3±28.8% (P<0.001) and alanine aminotransferase reduced from 33.8±16.6 to 15.7±5.5 mmol/l (P<0.001). Overall, HbA1c did not change, with baseline and follow up values of 50.5±16.2 and 44.5±13.2 mmol/mol, respectively (P=0.12), with a non-significant trend to reduction in DM patients from 62±13.2 to 53.3±11.8 mmol/mol (P=0.081). Overall, leptin came down from 40.6±24.8 to 30.8±30.4 ng/ml (P=0.16) and adiponectin increased from 4.48±1.58 to 8.92±6.36 μg/ml (P=0.004) while LAR came down from 8.88±4.76 to 5.26±6.52 ng/μg (P=0.036) and in DM patients from 8.2±3.5 to 5.1±3.2 ng/μg (P=0.038).

Conclusion: These preliminary data from a single centre study suggest that relatively high levels of insulin resistance, as evidenced by high LAR, are reduced 12 months after sleeve gastrectomy, both in patients with and without DM. Further studies are warranted to determine whether LAR can serve as a useful prognostic test or an indicator of metabolic response to bariatric surgery.