Weight loss and mortality risk in patients with T2DM

Takeaway

• In normal-weight patients with type 2 diabetes mellitus (T2DM), weight loss before T2DM diagnosis happened independently of established severe disease conditions and was not associated with the observed increased mortality risk.

Why this matters

• No previous studies evaluating obesity paradox in patients with T2DM was accompanied by a dedicated analysis of body weight changes pre- and post-diagnosis of T2DM.

Study design

• Retrospective longitudinal cohort study used 145,058 newly diagnosed patients (aged 18-70 years; 56% were male; 52% were current or ex-smokers) with T2DM from UK primary care from 2000 and followed them up to 2014.
• Primary outcome was all-cause mortality.
• Funding: None disclosed.

Key results

• At diagnosis, the mean BMI of patients with incident T2DM was 32.7 kg/m² and obesity was reported in 66% of them.
• Patients belonging to normal weight and overweight category reported a small but significant drop in body weight 6 months before T2DM diagnosis.
• Consistently increasing body weight was observed within the same time window among all categories of obese patients.
• Compared with grade 1 obese patients, normal weight patients in the no weight loss group (n=117,469) had 35% increased risk for mortality (aHR, 1.35; P<.01).
• However, among patients experiencing weight loss before diagnosis (n=27,589), no significant association between BMI categories and mortality risk was observed (all P>.05).

Limitations

• Reliable data on ethnicity and smoking cessation during follow-up were not available.