One study presents a three-item decision tool and another presents a quinolone alternative for cystitis.
Empiric treatment of cystitis with antibiotics (a common guideline recommendation) results in as many as 40% of symptomatic women unnecessarily receiving antibiotics (as confirmed by their negative culture results). A decision tool that could predict a positive culture would allow treatment to be more specific, to reduce costs, and to avoid the side effects of antibiotics.
Researchers tested a four-item decision tool in 422 nonpregnant women older than 16 from community-based practices throughout Canada. The four elements were symptoms for 1 day (vs. >1 day), dysuria, presence of leukocytes in greater than trace amounts (by dipstick), and presence of nitrates in any amount (by dipstick). Urine culture was performed for all patients. Duration of symptoms did not prove useful, whereas each of the remaining three items was significantly associated with a positive culture result. The number of items present was correlated with the proportion of positive cultures: Cultures were positive in 23% of women without any of the four criteria, in 43% with one, in 69% with two, and in 89% with three. A strategy of culture alone for women with zero or one criterion (with treatment based on culture results) and empiric treatment without culture for women with two or more criteria would have reduced urine cultures by 59% and unnecessary prescriptions by 40%.
Trimethoprim-sulfamethoxazole is the recommended drug of choice for the treatment of uncomplicated cystitis in women. However, Escherichia coli resistance is increasing, and some patients are allergic to the sulfa component. Fluoroquinolones traditionally have been the alternative, but they are expensive, and resistance to them is also growing. Nitrofurantoin is inexpensive and resistance to it is minimal, but the recommended treatment duration is 7 days.
In an unblinded study sponsored by the makers of nitrofurantoin, 338 women with cystitis symptoms and positive urine cultures at a university primary care clinic in the U.S. were randomized to either a 3-day course of trimethoprim-sulfamethoxazole (1 double-strength tablet twice per day) or a 5-day course of nitrofurantoin (Macrobid, 100 mg twice per day). Approximately 80% of patients in each group had a sustained cure for 30 days after the single course of treatment.
Comment: Any decision tool that relies on positive cultures to determine treatment is unlikely to be useful in an emergency department. The real message in the first study is that patients with two or more of the criteria should simply be treated empirically, without culture, but I suspect that this is what we are all doing anyway. Unfortunately, the study doesn’t help us with the difficult patients, those with zero or one criterion. The second study opens the door for 5-day treatment with nitrofurantoin (a time-tested agent with a low side-effect profile), which would reduce costs and help slow the rapid rise in quinolone-resistant bacteria by avoiding use of quinolones.
— J. Stephen Bohan, MD, MS, FACP, FACEP
Published in Journal Watch Emergency Medicine January 4, 2008
Citation(s):
McIsaac WJ et al. Validation of a decision aid to assist physicians in reducing unnecessary antibiotic drug use for acute cystitis. Arch Intern Med 2007 Nov 12; 167:2201.
Original article (Subscription may be required)
Medline abstract (Free)
Gupta K et al. Short-course nitrofurantoin for the treatment of acute uncomplicated cystitis in women. Arch Intern Med 2007 Nov 12; 167:2207.