Does Delaying Antibiotics for UTI in Over-65s Influence Risk of Bloodstream Infection?

Sarfaroj Khan 


October 07, 2020


  • Delaying or withholding antibiotics for suspected lower urinary tract infection (UTI) did not increase the risk of bloodstream infection (BSI) in adults aged ≥65 years.

  • However, the risk of mortality was increased in the subsequent 60 days.

Why this matters

  • Findings highlight the need for novel diagnostic and/or risk prediction strategies to guide antibiotic-prescribing decisions for suspected UTI.

Study design

  • This population-based study included 147,334 patients (aged, ≥65 years) with 280,462 distinct episodes of lower UTI using data from the UK Clinical Practice Research Datalink (CPRD) linked to Hospital Episode Statistics and census data (2007-2015).

  • Primary outcome: BSI within 60 days of UTI episodes, comparing patients treated immediately with antibiotics and those not treated immediately.

  • Funding: Economic and Social Research Council and Health Data Research UK.

Key results

  • BSI occurred in 0.4% (1025/244,963) of UTI episodes treated with immediate antibiotics vs 0.6% (228/35,499) of episodes without immediate antibiotics.

  • Delaying or withholding antibiotic treatment showed no statistically significant association with an increased likelihood of BSI in the following 60 days (adjusted OR [aOR], 1.13; 95% CI, 0.97-1.32; P=.105).

  • Women were less likely to develop BSI than men (aOR, 0.49; 95% CI, 0.43-0.55; P<.001).

  • Increasing age (aOR, 1.22; 95% CI, 1.18-1.27 per 5 years; P<.001) and social deprivation (aOR, 1.45; 95% CI, 1.19-1.76; P<.001) were independently associated with BSI.

  • Delaying or withholding antibiotics treatment was associated with an increased risk of mortality in the subsequent 60 days (aOR, 1.17; 95% CI, 1.09-1.26; P<.001); however, there was limited evidence that increased mortality was attributable to urinary-source BSI.


  • Risk of residual confounding.


Shallcross L, Rockenschaub P, Blackburn R, Nazareth I, Freemantle N, Hayward A. Antibiotic prescribing for lower UTI in elderly patients in primary care and risk of bloodstream infection: A cohort study using electronic health records in England. PLoS Med. 2020;17(9):e1003336. doi: 10.1371/journal.pmed.1003336. PMID: 32956399 View full text  

This clinical summary originally appeared on Univadis, part of the Medscape Professional Network.


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