In findings that have particular relevance in the COVID-19 pandemic, WA researchers have shown that ACE inhibitors and angiotensin receptor blockers (ARB) reduce the risk of pneumonia and influenza in people with type 2 diabetes.

Use of ACE inhibitors or ARB was associated with a one third lower risk of hospitalisation for lower respiratory tract infections, according to an analysis of data from 1,482 people with T2D enrolled in the Fremantle Diabetes Study.

Led by Professor Timothy Davis of the University of WA, the retrospective study with six years of follow up found that after adjusting for other variables, use of ACE inhibitors or ARB was was independently associated with a reduced risk of incident pneumonia/influenza requiring hospitalisation (cause-specific hazard ratio 0.64, p = 0.008).

The apparent protective effect was seen for both ACE inhibitors (HR 0.66) and ARB (HR 0.62) and was greater when patients used both drugs (HR 0.60).

A similar magnitude of reduced risk of pneumonia/influenza (HR 0.67) was seen when the data were analysed allowing for the competing risk of death. The study also showed there was no change over time in the use of ACE inhibitors or ARB by people with T2D, which were being used by about two thirds of patients at study entry.

It also confirmed that other plausible risk factors such as age, obesity and indigenous status were associated with higher risk of pneumonia/influenza.

Published in Diabetes Care journal, the findings of a protective effect from Renin-Angiotensin System Inhibitors were relevant beyond  the increased risk of respiratory infection and its morbidity and mortality in people with T2D, the study authors said.

“These data have implications for management, especially in an era in which lower–respiratory tract infections remain a major cause of hospitalisation for infection in people with diabetes, which is increasingly due to COVID-19,” they wrote.

Professor Davis and colleagues noted there was debate as to whether use of ACEi/ARB prescribed for conventional indications may facilitate the COVID-19 infection and its complications or, alternatively, confer cardiorespiratory protection, although most guidelines currently recommend that they not be stopped as a precaution.

“The present data provide some support for maintaining ACEi or ARB therapy in patients at risk or those with mild symptoms who are at low risk of acute kidney injury due to fluid loss,” they said.

“Our findings suggest that prevention of pneumonia/influenza in people with diabetes may represent a novel indication for these therapies, especially in situations such as the current COVID-19 pandemic where pulmonary infections are a particular concern,” they concluded.