OA Epidemiology

Angiotensin-Converting Enzyme Inhibitor Treatment and the Development of Urinary Tract Infections

Proceedings of the 2013 annual meeting of the Netherlands Epidemiology Society

Volume 1 Issue S1 Abstract 12

 

K.B. Pouwels, Unit of PharmacoEpidemiology and PharmacoEconomics (PE), Department of Pharmacy, University of Groningen, Groningen
S.T. Visser, Unit of PharmacoEpidemiology and PharmacoEconomics (PE), Department of Pharmacy, University of Groningen, Groningen
H.J. Bos, Unit of PharmacoEpidemiology and PharmacoEconomics (PE), Department of Pharmacy, University of Groningen, Groningen
E. Hak, Unit of PharmacoEpidemiology and PharmacoEconomics (PE), Department of Pharmacy, University of Groningen, Groningen

Background
Angiotensin-converting enzyme inhibitors (ACEi) can reduce the urine output, especially when treatment is started. Since bacterial clearance from the urinary tract is dependent on the urine output, it was hypothesized that ACEi also increase the risk of urinary tract infections (UTIs).

Methods
A prescription sequence symmetry analysis was performed  with a pharmacy prescription database. We selected all patients from the database that were incident users of both ACEi and nitrofurantoin (a proxy for UTIs). A maximum  time-span of four weeks between both prescriptions was used to limit time-variant  confounding. The sequence ratio (SR) was calculated by dividing the number of individuals starting ACEi first and nitrofurantoin second by the number of individuals starting nitrofurantoin treatment first and ACEi second. We adjusted for trends in prescribing and estimated 95% confidence intervals using exact confidence intervals for binomial distributions. To evaluate whether the effect is specific to ACEi, we also estimated the risk for β-blockers.

Results
In total, 22,959 incident users of ACEi therapy were eligible for analysis. Of these, 161 patients started ACEi therapy within 4 weeks prior to or after nitrofurantoin therapy initiation. 101 (63%) started ACEi therapy first followed by nitrofurantoin treatment while 60 (37%) patients started nitrofurantoin treatment first, which corresponds to an adjusted SR of 1.68 (95% CI 1.21-2.36). No association was found between β-blockers and urinary tract infection treatment (adjusted SR 1.01,  95%  CI 0.74-1.38).

Conclusions
This study suggests that ACEi therapy initiation, at least during the first month, increases the risk of developing UTIs.

Published: 06 Jun, 2013

 
Licensee OA Publishing London 2013. Creative Commons Attribution License (CC-BY)