The impact of type 2 diabetes on polycystic ovary syndrome in patients undergoing sleeve gastrectomy.

Study question: Does the concurrent type 2 diabetes mellitus (T2DM) aggravate the features and prognosis of PCOS in patients undergoing sleeve gastrectomy (SG)?

Summary answer: For patients undergoing SG with obesity, concurrent T2DM is associated with aggravated metabolic but milder reproductive features of PCOS and did not attenuate the resumption of regular menstruation for up to 1 year after surgery.

What is known already: Women with T2DM have an increased risk of PCOS. However, whether concurrent T2DM further increases the disease burden and treatment difficulty of PCOS in patients with obesity requires further investigation.

Study design, size, duration: This was a single-center, two-arm, prospective, cohort study enrolling a total of 329 women with PCOS and scheduled for SG because of obesity at an university-affiliated hospital between January 2020 and August 2023, with a 1-year follow-up after surgery.

Participants/materials, setting, methods: Comparisons were made between patients with T2DM (PCOS+T2DM) and without (PCOS) to examine the impact of T2DM on the metabolic, reproductive, and psychological features of PCOS. The follow-up data of weight loss and menstruation were analyzed to determine the impact of T2DM on PCOS prognosis for up to 1 year after SG.

Main results and the role of chance: After controlling for confounders, patients in the PCOS+T2DM group (n = 98) showed more severe insulin resistance, glucose intolerance, dyslipidemia, and non-alcoholic fatty liver disease (NAFLD) (NAFLD activity score 4.31 ± 1.15 versus 3.52 ± 1.42, P < 0.001) than those in the PCOS group (n = 149). In addition, the PCOS+T2DM group had a lower level of total testosterone (1.63 ± 0.69 versus 1.82 ± 0.76, P = 0.045), a lower ratio between luteinizing hormone and follicle-stimulating hormone (median 1.48 versus 1.68, P = 0.030), and a lower proportion of patients with polycystic ovarian morphology (88% versus 96%, P = 0.022) than the PCOS group. As a result, the two groups differed significantly in terms of the Rotterdam classification of PCOS (P = 0.009). No significant difference was detected by group in the psychological features of PCOS except a lower degree of emotional eating in the PCOS+T2DM group (P = 0.001). Although the PCOS+T2DM group took longer to resume regular menstruation after SG (P = 0.037), the two groups had similar proportions of patients with regular menstruation (85% versus 87%, P = 0.758) 1 year after SG, which was further confirmed by subgroup analyses by body mass index.

Limitations, reasons for caution: The prognosis of PCOS after SG mainly focused on the results of menstruation rather than a complete evaluation of the remission of the disease.

Wider implications of the findings: Our study showed that, for patients with obesity, concurrent T2DM is associated with aggravated metabolic but milder reproductive features of PCOS and did not attenuate the resumption of regular menstruation for up to 1 year after surgery. Our study also highlights the need for high-quality studies with a more comprehensive evaluation of the impact of T2DM on the prognosis of patients with PCOS after SG.

Study funding/competing interest(s): This study was funded by the National Natural Science Foundation of China Grants (82100853), the Natural Science Foundation of Shandong Province of China (ZR2021QH028), and the Clinical Research Project of Shandong University (2020SDUCRCC024). The authors have no conflicts of interest.

Trial registration: Chinese Clinical Trial Registry with No. ChiCTR1900026845.