Semaglutide vs dulaglutide in UK practice

A population-based cohort study published in The Lancet Regional Health: Europe compared once-weekly injectable semaglutide with dulaglutide in 6,616 adults with type-2 diabetes managed in UK primary care^[1]. Over one year of follow-up, semaglutide users saw a 0.22 percentage-point greater reduction in HbA1c and lost 1.92 kg more body weight than dulaglutide users. The study also found that most participants (87.7%) would not have met the eligibility criteria for the head-to-head randomised trial (SUSTAIN-7) that regulators originally used to compare these two drugs.

The numbers from routine care

Researchers identified 1,901 new semaglutide users and 2,735 new dulaglutide users from UK primary-care records between 2019 and 2022. After propensity-score matching for baseline characteristics, the estimated treatment difference in HbA1c at one year was -0.22 percentage points (95% CI -0.30 to -0.15) in favour of semaglutide^[1]. The body-weight difference was -1.92 kg (95% CI -2.91 to -0.93), again favouring semaglutide.

These effect sizes are smaller than the differences seen in SUSTAIN-7, the randomised controlled trial that compared semaglutide 0.5 mg and 1 mg against dulaglutide 0.75 mg and 1.5 mg^[4]. That is expected. Routine-care populations are older, have more comorbidities, and are less likely to adhere to scheduled dosing than trial participants. The value of a study like this is precisely that it captures what happens outside the controlled trial setting.

Most real-world patients would not qualify for the trial

Only 12.3% of the cohort met the eligibility criteria used in SUSTAIN-7. Among the 87.7% who did not, the HbA1c difference remained similar (-0.23 percentage points) and the weight difference was actually slightly larger (-2.01 kg)^[1]. This matters because regulators and prescribers rely on trial data that may not reflect the people who actually receive the drug. The study's authors note that real-world evidence like this fills that gap.

What about side effects and discontinuation

About 29.9% of participants in both groups stopped treatment within the first year. Early discontinuers had higher rates of gastrointestinal events (23.5 to 26.1 per 100 person-years) compared with those who stayed on treatment (10.6 to 13.8 per 100 person-years)^[1]. The study did not find a meaningful safety difference between the two drugs.

Both semaglutide (sold as Ozempic for type-2 diabetes) and dulaglutide (sold as Trulicity) are GLP-1 receptor agonists with well-characterised gastrointestinal side-effect profiles^[2][3]. Nausea, vomiting, and diarrhoea are common across the class and tend to be dose-dependent. The 70.1% of patients who stayed on treatment past one year reported lower GI event rates, which is consistent with the slow-titration approach described in both drugs' prescribing information.

What this study does not tell us

The study covers one year of follow-up. It cannot speak to longer-term outcomes such as cardiovascular events, kidney-disease progression, or weight trajectory beyond 12 months. The SELECT trial showed cardiovascular benefit for semaglutide in a different population (obesity without diabetes), but whether semaglutide's modest advantage over dulaglutide in glycaemic control translates to a meaningful difference in hard endpoints for type-2 diabetes patients remains an open question.

The cohort also does not include the higher semaglutide doses now available (2 mg Ozempic), which could widen the gap. And because the data come from UK primary care, the results may not generalise directly to other healthcare systems with different prescribing patterns, formulary constraints, and patient demographics. The authors acknowledge that residual confounding from unmeasured variables is always a limitation of observational data, even after propensity-score matching.

Where this fits for readers

For patients with type-2 diabetes choosing between these two weekly injectables, the study confirms that semaglutide offers a modest advantage in both blood-sugar and weight outcomes under routine conditions, not just in clinical trials. That said, individual response varies. Some patients who do not tolerate one GLP-1 agonist do well on the other, and the choice involves tolerability, cost, and access considerations that differ by country and by payer.

Dulaglutide remains widely prescribed, particularly where semaglutide supply has been constrained or where formulary rules favour it. This study does not make a case for switching everyone. It adds a data point: in a large, representative UK population, semaglutide produced slightly better glycaemic and weight outcomes at one year. For the regulatory picture, see the semaglutide regulation and access pages. The decision on which drug to use belongs with a prescribing clinician who knows your history.