Recurrent UTIs in Women: How to Refine Your Care

For the third time in nine months, Joan, 28, presents with complaints of painful, frequent, and urgent urination. Joan is sexually active; her medical history is otherwise unremarkable. In each of the previous two episodes, her urine culture grew Escherichia coli, and she was treated with a five-day course of nitrofurantoin. Now, she asks about the need for additional workup and treatment, as well as whether there is a way to prevent further infections.

Urinary tract infections (UTIs) are the most common bacterial infection in women and account for an estimated 5.4 million primary care office visits and 2.3 million emergency department visits annually.^1,2 For women, the lifetime risk for a UTI is greater than 50%.³ In one study of UTI in a primary care setting, 36% of women younger than 55 and 53% of women older than 55 had a recurrent infection within a year.⁴ Most women with UTI are treated as outpatients, but 16.7% require hospitalization.⁵ In the United States, direct costs for evaluation and treatment of UTI total $1.6 billion each year.⁵

Accurately characterizing recurrent UTI

Bacteriuria is defined as the presence of 100,000 colony-forming units (ie, viable bacteria) per milliliter of urine collected midstream on two consecutive urinations.⁶ UTIs are symptomatic infections of the urinary tract and may involve the urethra, bladder, ureters, or kidneys.⁷ Infections of the lower tract (bladder and urethra) are commonly referred to as cystitis; infections of the upper tract (kidney and ureters) are referred to as pyelonephritis.

Most UTIs are uncomplicated and do not progress to more serious infections. However, patients who are pregnant or who have chronic medical conditions (eg, renal insufficiency or use of immunosuppressant medications), urinary obstruction, or calculi may develop complicated UTIs.⁸

Recurrent UTI is an infection that follows resolution of bacteriuria and symptoms of a prior UTI; the term applies when such an infection occurs within six months of the previous UTI or when three or more UTIs occur within a year.⁷ Recurrent infection can be further characterized as relapse or reinfection. Relapse occurs when the patient has a second UTI caused by the same pathogen within two weeks of the original treatment.⁹ Reinfection is a UTI that occurs more than two weeks after completion of treatment for the original UTI. The pathogen in a reinfection may be the same one that caused the original UTI or it may be a different agent.⁹

It’s also important to differentiate between recurrent and resistant UTI. In resistant UTI, bacteriuria fails to resolve following seven to 14 days of appropriate antibiotic treatment.⁹

FACTORS THAT INCREASE RISK FOR RECURRENT UTI

Premenopausal women

Both modifiable and nonmodifiable factors (see Table 1) have been associated with increased risk for recurrent UTI in premenopausal women.^10-21 Among those with specific blood group phenotypes (Lewis non-secretor, in particular), rates of UTI rise secondary to increased adherence of bacteria to epithelial cells in the urinary tract.¹⁰ Other nonmodifiable risk factors include congenital urinary tract anomalies, obstruction of the urinary tract, and a history of UTI.^11,12 Women whose mothers had UTIs are at higher risk for recurrent UTI than are those whose mothers had no such history.¹³

Modifiable risk factors for recurrent UTI include contraceptive use (spermicides, spermicide-coated condoms, and oral contraceptives) and frequency of intercourse (≥ 4 times/month).¹³ Spermicides alter the normal vaginal flora and lead to increased colonization of E coli, which increases the risk for UTI.¹⁴ Women with recurrent UTIs were 1.27 to 1.45 times more likely to use oral contraceptives than those without recurrent UTIs.¹³ Compared with college women who had not had intercourse, sexually active college women who had engaged in intercourse three times in a week had a 2.6-fold increase in relative risk for UTI.¹⁵ Those who had daily intercourse had a 9-fold increase in relative risk for UTI.¹⁵This elevated risk is due to trauma to the lower urogenital tract (urethra) and introduction of bacteria into the urethra via mechanical factors.^16,17

Postmenopausal women

Atrophic vaginitis, catheterization, declining functional status, cystocele, incomplete emptying, incontinence, and history of premenopausal UTIs are all risk factors for recurrent UTI in postmenopausal women.^19,20 Decreased estrogen and resulting vaginal atrophy appear to be associated with increased rates of UTI in these women. Additionally, postmenopausal women’s vaginas are more likely to be colonized with E coli and have fewer lactobacilli than those of premenopausal women, which is thought to predispose them to UTI.²¹ These risk factors are summarized in Table 1.^10-21