Table 3:

Treatment failure in patients with relatively low and relatively high eGFR

Indicator of failure* and drugNo. with event/ total no. of patients (%)OR (95% CI)
UnadjustedAdjusted
Relatively low eGFR
Second prescription
Nitrofurantoin516/3 739 (13.8)1.001.00
Ciprofloxacin130/1 989 (6.5)0.44 (0.36–0.53)0.43 (0.35–0.53)
Norfloxacin133/2 032 (6.5)0.44 (0.36–0.53)0.44 (0.36–0.54)
TMP–SMX184/1 463 (12.6)0.90 (0.75–1.08)0.92 (0.77–1.10)
Hospital encounter with UTI
Nitrofurantoin95/3 739 (2.5)1.001.00
Ciprofloxacin21/1 989 (1.1)0.41 (0.25–0.66)0.40 (0.25–0.64)
Norfloxacin24/2 032 (1.2)0.46 (0.29–0.72)0.45 (0.28–0.71)
TMP–SMX31/1 463 (2.1)0.83 (0.55–1.25)0.81 (0.53–1.22)
Relatively high eGFR§
Second prescription
Nitrofurantoin7 759/70 758 (11.0)1.001.00
Ciprofloxacin1 713/29 095 (5.9)0.51 (0.48–0.54)0.50 (0.47–0.53)
Norfloxacin2 734/45 116 (6.1)0.52 (0.50–0.55)0.54 (0.52–0.57)
TMP–SMX3 683/37 665 (9.8)0.88 (0.84–0.92)0.93 (0.89–0.97)
Hospital encounter with UTI
Nitrofurantoin863/70 758 (1.2)1.001.00
Ciprofloxacin241/29 095 (0.8)0.68 (0.59–0.78)0.65 (0.56–0.75)
Norfloxacin272/45 116 (0.6)0.49 (0.43–0.56)0.51 (0.44–0.58)
TMP–SMX412/37 665 (1.1)0.90 (0.80–1.01)0.93 (0.83–1.05)
  • Note: CI = confidence interval, eGFR = estimated glomerular filtration rate, OR = odds ratio, TMP–SMX = trimethoprim–sulfamethoxazole, UTI = urinary tract infection.

  • * The follow-up time was the 14 days following antibiotic dispensing.

  • Analyses were adjusted for age, year of cohort entry, rural residence, duration of initial antibiotic prescription (≤ 7 d v. > 7), prior number of antibiotic prescriptions, prior number of urine cultures, number of unique medications, dementia, stroke, diabetes mellitus and urinary incontinence.

  • Cohort with relatively low eGFR: the algorithm of database codes identified patients with a median eGFR of 38 (IQR 27–52) mL/min per 1.73 m2. (19)

  • § Cohort with relatively high eGFR (absence of chronic kidney disease): the algorithm of database codes identified patients with a median eGFR of 69 (IQR 56–82) mL/min per 1.73 m2. (19)