This cohort study presented a comprehensive real-world comparative effectiveness analysis of liraglutide and dulaglutide in a Taiwanese population with type 2 diabetes mellitus. The results revealed that both liraglutide and dulaglutide were associated with similar composite cardiovascular outcomes in patients with type 2 diabetes. Furthermore, there was no disparity observed in composite renal outcomes or their individual components between the liraglutide and dulaglutide groups. Additionally, our study indicated similar rates of all-cause mortality between the two groups. Taken together, liraglutide and dulaglutide have similar effects in preventing cardiovascular diseases, delaying kidney diseases and all-cause mortality.
Cardiovascular outcomes
Our study indicated comparable clinical effectiveness in composite cardiovascular outcomes between liraglutide and dulaglutide. The LEADER and REWIND trials provided evidence supporting the reduction of death from cardiovascular causes and non-fatal stroke, respectively. The potential mechanisms of GLP-1 RAs in mediating cardiovascular protection are not solely explained by lowering serum glucose levels. Other potential mechanisms, such as reducing inflammatory processes, improving vascular function to decrease blood pressure, and promoting more stabilized, less vulnerable plaques, have also been reported. [16–19]
In Taiwan, most people used liraglutide and dulaglutide during our study period. The LEADER trial included a higher proportion of patients with very high cardiovascular risk (81%), whereas the REWIND trial included a lower proportion of high-risk patients (31%). [2, 3] This difference in patient populations suggests variation in the study groups. One meta-analysis discussed the cardiovascular protective effects between populations with and without established cardiovascular disease, finding no significant difference in the benefits of GLP-1 receptor agonists (GLP-1 RAs) on major adverse cardiovascular events (MACE) between these groups. [20] Despite this, direct comparisons of cardiovascular effectiveness between dulaglutide and liraglutide remain limited. Our retrospective study examined type 2 diabetes mellitus (DM) patients receiving either liraglutide or dulaglutide treatment to assess the impact of these medications on cardiovascular outcomes. We found no significant differences in composite cardiovascular outcomes between the liraglutide and dulaglutide groups. GLP-1 RAs also exert multiple effects on cardiovascular risk factors, including reductions in systolic blood pressure and LDL cholesterol, improved glycemic control, and body weight reduction. [21, 22] Our study found that dulaglutide contributed to better glycemic control, while liraglutide led to a larger reduction in body weight. Additionally, we observed no significant differences in systolic and diastolic blood pressure or heart rate between the liraglutide and dulaglutide groups. These findings may help explain the comparable composite cardiovascular outcomes observed over the three-year follow-up period. Our study provides real-world evidence on the cardiovascular effectiveness of both liraglutide and dulaglutide.
Renal outcomes
Our study found no significant differences between the liraglutide group and the dulaglutide group regarding composite renal outcomes, reduction of estimated glomerular filtration rate, and the incidence of new macroalbuminuria. Currently, there is limited data available on the use of liraglutide and dulaglutide in patients with more advanced stages of chronic kidney disease (CKD).[23] The LEADER and REWIND studies demonstrated benefits in composite renal outcomes, primarily due to a reduction in the incidence of new-onset macroalbuminuria. However, these trials excluded patients with more advanced CKD stages, defined as an estimated glomerular filtration rate (eGFR) less than 30 ml/min/1.73 m^2 and 15 ml/min/1.73 m^2, respectively [5, 6]. Only one Japanese cohort study reported a significant reduction in eGFR decline in stage 5 CKD patients.[24] Additionally, GLP-1 receptor agonists (GLP-1RAs) exert their effects on the kidneys by increasing renal plasma flow and glomerular filtration rate through GLP-1 receptors, and these effects may vary depending on the underlying renal pathology. [25] As a result, the renal protective effect of GLP-1RAs in patients with type 2 diabetes and advanced CKD remains inconclusive. Our study provided evidence of a comparable renal protective effect with liraglutide and dulaglutide treatment in patients with CKD and type 2 diabetes. Liraglutide seemed to have a better effect in advanced stages of CKD (eGFR 15–29 ml/min/1.73m).
Secondary Outcomes
We found no significant differences of all-cause death between two groups. Our liraglutide group exhibited comparable composite cardiovascular outcome, composite renal outcome, cardiovascular death, and heart failure admission compared to dulaglutide group. There finding may indirectly account for the comparable rates of all-cause death. Additionally, we demonstrated better weight control with liraglutide, consistent with the result of the AWARD-6 trial, which showed significantly larger body weight reduction associated with liraglutide compared to dulaglutide at 26 weeks.[26] The reason for the different effects on body weight is that dulaglutide is less transported across the blood–brain barrier or through fenestrated capillaries than liraglutide, thereby contributing less to satiety effects in the central nervous system [27] Moreover, dulaglutide resulted in a larger decrease in glycosylated hemoglobin. The AWARD-6 trial demonstrated the non-inferiority of reduction in HbA1c of dulaglutide versus liraglutide at 26 weeks.[26] Interestingly, a Japanese trial also showed the comparable effect on lowering HbA1c effect at 26 weeks.[28] However, with a longer follow-up period, the Japanese trial reported significant HbA1c reduction for dulaglutide versus liraglutide at 52 weeks.[29] Our real-world study is consistent with previous research and demonstrates greater benefits of glycemic control associated with the use of dulaglutide compared to liraglutide over a three-year follow-up period, with differences becoming apparent as early as six months into the study.