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27-01-2011 | Diabetes | Article

DPP-4 inhibitors linked to increased respiratory infection risk


Free abstract

MedWire News: Study results suggest that Type 2 diabetic patients treated with the dipeptidyl peptidase-4 (DPP-4) class of drugs may experience more upper respiratory tract infections than those given other oral antidiabetes agents.

Aukje Mantel-Teeuwisse (Utrecht Institute for Pharmaceutical Sciences, The Netherlands) and colleagues carried out a nested case-control study using information collected from the World Health Organization-Adverse Drug Reactions (WHO-ADR) database.

They assessed ADRs, particularly those classified as "infection", for antidiabetes drugs using the Medical Dictionary for Regulatory Activities classification system.

Writing in the journal Diabetes Care, the team says that 305,415 suspected ADRs (106,469 case reports) from antidiabetes drugs were identified between 1999 and 2009. Patients reporting ADRs were aged 59.7 years on average and 59.6% were women.

Patients treated with DPP-4 inhibitors (8083 ADR reports overall; 242 infections) had a higher risk for infection than those treated with any of the other antidiabetes drug groups in the study, such as biguanides, insulins, or thiazolidinediones.

Using patients treated with biguanides like metformin as a comparison group (21,763 reports overall; 289 infections), DPP-4-treated patients were a significant 2.3 times more likely to experience an infection ADR.

When divided by infection type, such as upper or lower respiratory tract infection, and urinary tract infection, the researchers found that the increased infection risk seen in patients treated with DPP-4 inhibitors was largely accounted for by a 12.3-fold increased risk for upper respiratory tract infections experienced by these individuals.

Mantel-Teeuwisse and co-authors suggest that this apparent increase in risk could occur because "the effect of DPP-4 inhibitors results in a slight imbalance of the immune system that causes an increased risk of common, less severe infections such as (viral) upper respiratory infections."

They conclude: "Although the limitations of spontaneous reporting systems (eg, underreporting, the Weber-effect, reporting bias) should be taken into account, physicians and patients nevertheless should remain vigilant on the occurrence of infections and continue to report infections as possible ADRs.

"Infections may be related to diabetes, but a direct effect of the medication on the occurrence of infections should be considered."

MedWire ( is an independent clinical news service provided by Current Medicine Group, a trading division of Springer Healthcare Limited. © Springer Healthcare Ltd; 2011

By Helen Albert