Focus on diet quality
People treated with tirzepatide “eat so little food that we need to improve the quality of what they eat to protect their muscle,” commented Carel le Roux, MBChB, PhD, a professor in the Diabetes Complications Research Centre of University College Dublin. “You no longer need a dietitian to help people lose weight, because the drug does that. You need dietitians to look after the nutritional health of patients while they lose weight,” Dr. le Roux said in a separate session at the meeting.
Mitchel L. Zoler/MDedge News
Dr. Carel le Roux
Additional tests showed that blood glucose and insulin levels were all significantly lower among trial participants on all three doses of tirzepatide compared with those on placebo, and the tirzepatide-treated subjects also had significant, roughly twofold elevations in their insulin sensitivity measured by the Matsuda Index.
The impact of tirzepatide on glucose and insulin levels and on insulin sensitivity was similar regardless of whether study participants had normoglycemia or prediabetes at entry. By design, no study participants had diabetes.
The trial assessed patient-reported quality-of-life outcomes using the 36-Item Short Form Survey (SF-36). Participants had significant increases in all eight domains within the SF-36 at all three tirzepatide doses, compared with placebo, at 72 weeks, Dr. Jastreboff reported. Improvements in the physical function domain increased most notably among study participants on tirzepatide who had functional limitations at baseline. Heart rate rose among participants who received either of the two highest tirzepatide doses by 2.3-2.5 beats/min, comparable with the effect of other injected incretin-based treatments.
Lipids improve in those with type 2 diabetes
Tirzepatide treatment also results in a “secondary effect” of improving levels of several lipids in people with type 2 diabetes, according to a meta-analysis of findings from six randomized trials. The meta-analysis collectively involved 4,502 participants treated for numerous weeks with one of three doses of tirzepatide and 2,144 people in comparator groups, reported Dr. Karagiannis, a diabetes researcher at Aristotle University of Thessaloniki (Greece).
Among the significant lipid changes linked with tirzepatide treatment, compared with placebo, were an average 13 mg/dL decrease in LDL cholesterol, an average 6 mg/dL decrease in VLDL cholesterol, and an average 50 mg/dL decrease in triglycerides. In comparison to a GLP-1 receptor agonist, an average 25 mg/dL decrease in triglycerides and an average 4 mg/dL reduction in VLDL cholesterol were seen. And trials comparing tirzepatide with basal insulin saw average reductions of 7% in LDL cholesterol, 15% in VLDL cholesterol, 15% in triglycerides, and an 8% increase in HDL cholesterol.
Dr. Karagiannis highlighted that the clinical impact of these effects is unclear, although he noted that the average reduction in LDL cholesterol relative to placebo is of a magnitude that could have a modest effect on long-term outcomes.
These lipid effects of tirzepatide “should be considered alongside” tirzepatide’s “key metabolic effects” on weight and hemoglobin A1c as well as the drug’s safety, concluded Dr. Karagiannis.
The tirzepatide trials were all funded by Eli Lilly, which markets tirzepatide (Mounjaro). Dr. Jastreboff has been an adviser and consultant to Eli Lilly, as well as to Intellihealth, Novo Nordisk, Pfizer, Rhythm Scholars, Roche, and Weight Watchers, and she has received research funding from Eli Lilly and Novo Nordisk. Dr. Karagiannis had no disclosures. Dr. le Roux has had financial relationships with Eli Lilly, as well as with Boehringer Ingelheim, Consilient Health, Covidion, Fractyl, GL Dynamics, Herbalife, Johnson & Johnson, Keyron, and Novo Nordisk.