We read with interest the article by Singh and collegues suggesting that nitrofurantoin is effective for treating urinary tract infections (UTIs) in older women with lower glomerular filtration rates (GFRs).1
The prevalence of asymptomatic bacteriuria is very high in older people. However, antibiotics are not indicated, because they do not prevent symptomatic UTI, complications or death.2 Although antibiotics are superior to placebo for treating asymptomatic bacteriuria, the increase in the rate of adverse events is substantial.2 In clinical practice, many older people with asymptomatic bacteriuria are prescribed antibiotics without clear indications. In this study, it was not distinguished from UTI, which may affect the results of the study.
In the discussion section, the authors state that the use of nitrofurantoin for patients with lower GFRs may relieve the pressure to prescribe fluoroquinolones. However, the findings of the study indicate that nitrofurantion is more commonly used than fluoroquinolones, and the effectiveness of nitrofurantoin is substantially lower. Encouraging the use of antibiotics with lower efficacy may be especially problematic in older people, who are at increased risk for UTI-associated sepsis.
Although antibiotic prescription in the 120 days before the index date is an exclusion criterion, the patients had high rates of urine culture and history of antibiotic use. Because long-term antibiotic prophylaxis is indicated when there is a history of three or more UTIs in the last 12 months,3 long-term use of prophylactic antibiotics might have been planned for some of these patients in the index date. In the long-term, adverse events, such as pulmonary toxicity and neuropathy associated with nitrofurantoin, may be important.4