UTIs can be better understood by analyzing their incidence in women's age groups and other demographics, by their causes, by risk factors for their occurrence, and by treatment forms for women of different ages and circumstances.
Incidence of UTIs in Women by Age Group
- The 15-19 age group of women has the highest rate of UTIs: about 3.2 percent per 100,000 women.
- The next highest incidence is in women over 65--about double the rate of other age cohorts (except 15-19).
- The incidence in women 20-24, 25-29, 30-34, 35-39, 40-44, 45-49, 50-54, 55-59, and 60-64 is just under, at, or over 2 percent per 100,000 women. (The source of this information has a chart depicting the incidence in these 5-year age cohorts.)
Incidence of UTIs in Women by Other Demographics
- By race: "A retrospective analysis of 24,000 births found the prevalence of UTI during pregnancy to be 28.7 percent in whites and Asians, 30.1 percent in blacks, and 41.1 percent in Hispanics. When socioeconomic status is controlled for, no significant interracial differences seem to exist."
- By socioeconomic status: It can be inferred from the retrospective study that socioeconomic status is a factor in incidence of UTIs among women, but no specific study was found that focused on this variable.
- By pregnancy status: In one study that focused on pregnant women, 10 percent of the women "had a diagnosis of a UTI just before or during pregnancy." Another study found that the incidence of UTIs in pregnant women was no different from the incidence in nonpregnant women.
- By exposure to healthcare: "Healthcare-associated UTIs (HAUTIs) represent the largest subtype among all healthcare-associated infections. The prevalence of HAUTIs assessed in regional studies ranges from 12.9 percent in the US and 19.6 percent in Europe, to up to 24 percent in developing countries."
Common Causes and Risk Factors in Women Contracting UTIs
Causes of UTIs
- Most UTIs (80 percent to 90 percent) are caused by E.coli.
- The rest of UTI infections (10–20 percent) are caused by organisms such as Staphylococcus saprophyticus, Proteus, Pseudomonas, Klebsiella, and Enterobacter species.
Risk Factors for UTIs to Occur
- For premenopausal women: The risk factors include a "history of urinary tract infection, frequent or recent sexual activity, diaphragm contraception use, use of spermicidal agents, increasing parity, diabetes mellitus, obesity, sickle cell trait, anatomic congenital abnormalities, urinary tract calculi, neurologic disorders or medical conditions requiring indwelling or repetitive bladder catheterization".
- For postmenopausal women: Risk factors include "vaginal atrophy; incomplete bladder emptying; poor perineal hygiene; rectocele, cystocele, urethrocele, or uterovaginal prolapse; lifetime history of urinary tract infection, Type 1 diabetes mellitus". In addition, risk factors include the changes in immune function that come with age, "exposure to nosocomial pathogens, and an increasing number of comorbidities [that] put the elderly at an increased risk for developing infection."
- For institutionalized older women: Risk factors include "the presence of a urinary catheter and ...history of prior UTI." The "predictive factors include disability in activities of daily living and having a history of urinary incontinence".
Treatments for UTIs in Premenopausal Women
- Treatment of premenopausal women depends on which of four types of UTI the women are diagnosed with.
- The four types are: Uncomplicated UTI, Acute uncomplicated cystitis, Acute uncomplicated pyelonephritis, Asymptomatic bacteriuria.
- Uncomplicated UTI is treated with one of the following antibiotics: "trimethoprim-sulfamethoxozole, ciprofloxacin, nitrofurantoin macrocrystals, nitrofurantoin monohydrate macrocrystals, or fosfomycin tromethamine"
- Treatment recommendations are changing for uncomplicated acute cystitis. "In the past, uncomplicated acute cystitis has been treated with 7–10 days of antimicrobial therapy. However, recent data have shown that 3 days of therapy" works just as well, and leads to "eradication rates exceeding 90 percent".
- Acute uncomplicated pyelonephritis: This disease "traditionally has been treated with hospitalization and parenteral antibiotics. However, there has been a recent shift to outpatient management... [with] 14 days of oral or parenteral antibiotics or both ...now standard, with cure rates approaching 100 percent." About 7 percent of cases require hospitalization.
- UTI recurrences are treated with "continuous prophylaxis with once-daily treatment with nitrofurantoin, norfloxacin, ciprofloxacin, trimethoprim, trimethoprim–sulfamethoxazole, or another agent ...." These drugs have "been shown to decrease the risk of recurrence by 95 percent. This can be continued for 6–12 months and then reassessed."
- At least two of the antibiotics used to treat UTIs, nitrofurantoin and trimethoprim-sulfamethoxazole, "have been linked to birth defects." These treatments should be avoided for pregnant patients.
- Nitrofurantoin (brand name Macrobid) is used in 32 percent of UTIs in the US.
- Trimethoprim-sulfamethoxazole (Bactrim) is a combination of two drugs and is used in 26 percent of UTIs in the US.
- Fosfomycin (Monurol), a new drug, is taken once, but is expensive and rarely prescribed.
- Ciprofloxacin (Cipro) is used in 35 percent of uncomplicated UTIs, while levofloxacin is used in 2 percent. These antibiotics can have dangerous side effects.
Treatment of UTIs in Postmenopausal Women
- The course of treatment for uncomplicated UTI in older women is similar to the treatment for younger women depending on which bacterium is present.
- Treatment guidelines "recommend nitrofurantoin monohydrate/macrocrystals 100 mg twice daily for 5 days, or trimethoprim–sulfamethoxazole 160/800 mg twice daily for 3 days, if local resistance rates do not exceed 20 percent."
- E. coli (the most common source of UTI infection) has low resistance rates to nitrofurantoin. But "other Enterobacteraciae species, which are more common in older adults, may have intrinsic resistance to nitrofurantoin."
- Patients who have chronic kidney disease, should not be prescribed nitrofurantoin. Instead, "trimethoprim–sulfamethoxazole should be the preferred empiric oral option for treatment of clinically suspected UTI in older adults."
- "Fluoroquinolones are among the most prescribed antibiotics for UTI, but resistance to these antimicrobials is high and they should only be used if sensitivity testing is performed."
- In older women who have had recurrent UTIs, additional measures include prevention strategies. These include "use of antibiotic prophylaxis and nonantimicrobial therapies, such as estrogen replacement therapy and cranberry formulations."
- "A study by Avorn et al. demonstrated that among women living in nursing homes and assisted living facilities, 10 ounces (300 ml) of cranberry juice cocktail reduced bacteriuria plus pyuria at 6 months of follow-up."
We located nearly a dozen reports of studies and reviews of study results, but most did not use the age breakdown requested for this research project. Since the raw data was not provided in the reports, we did not attempt to alter the age cohorts cited by the authors to fit them into the format requested. In order to do that with accuracy, we would have needed to use the original datasets.