Top POEMs of 2013: Renal Disease

Three Questions to Diagnose UTI in Women

Clinical question: Can urinary tract infections be simply diagnosed in women using history alone?

Bottom line: History alone can correctly classify slightly more than half the women with suspected urinary tract infections (UTIs). (LOE = 2b)

Reference: Knottnerus BJ, Geerlings SE, Moll van Charante EP, Ter Riet G. Toward a simple diagnostic index for acute uncomplicated urinary tract infections. Ann Fam Med 2013;11(5):442-451.

Study design: Cross-sectional

Funding source: Unknown/not stated

Setting: Outpatient (primary care)

Synopsis: The 196 women in this study complained of dysuria for less than 1 week, were 12 years or older, and were recruited from primary care practices in the Netherlands. The researchers excluded: pregnant or lactating women; those with symptoms of pyelonephritis; recent antibiotic use; recent urologic procedures; known structural or functional anomalies; and an immunocompromised state. Each patient underwent a structured clinical assessment and submitted a urine sample for dipstick testing, a urinalysis, and culture. The gold standard for UTI diagnosis was more than 10^3 colony-forming units of a single uropathogen per milliliter. Additionally, the authors polled practicing clinicians and learned that clinicians believe that probabilities of less than 30% and more than 70% are clinically meaningful for guiding UTI treatment decisions. The authors then did a bunch of statistical stuff to identify a range of factors that might discriminate women with UTIs from those without UTIs. This generated several models using only the history or various combinations of the history and various urine tests. As in many other studies, the prevalence of UTI in these women was 61%. Using only the history correctly classified more than half of the women. Three factors arose as important: (1) a positive response to "Do you think you have a UTI?"; (2) a positive response to having significantly severe dysuria; and (3) a negative response to having vaginal irritation. These items correctly classified 56% of women with a less than 30% or more than 70% likelihood of having a UTI. Adding a urine dipstick test increased the likelihood to 73%. However, performing a dipstick test only for women whose responses are mixed (placing their likelihood of UTI between 30% and 70%) increased the diagnostic accuracy to 83%. Finally, these authors found that neither examining the urine sediment nor the dipslide test were very useful.

Henry C. Barry, MD, MS
Michigan State University
East Lansing, MI

Most Antibiotics Similar in Efficacy for Lower UTI

Clinical question: What is the best antibiotic for the treatment of uncomplicated lower urinary tract infection?

Bottom line: This network meta-analysis found that the antibiotics commonly used to treat lower urinary tract infection (UTI) are similar in efficacy, with one exception: amoxicillin-clavulanate is significantly less effective than the others. (LOE = 1a)

Reference: Knottnerus BJ, Grigoryan L, Geerlings SE, et al. Comparative effectiveness of antibiotics for uncomplicated urinary tract infections: Network meta-analysis of randomized trials. Fam Pract 2012;29(6):659-670.

Study design: Meta-analysis (randomized controlled trials)

Funding source: Self-funded or unfunded

Setting: Various (meta-analysis)

Synopsis: A network meta-analysis is a technique that allows a researcher to compare 2 treatments via a common comparison group. For example, if one study compared drug A with drug B, and a second study compared drug B with drug C, a network meta-analysis allows us to indirectly compare drug A with drug C. This study compared antibiotics for the treatment of lower UTI. After a careful search, a total of 10 studies comparing 8 antibiotics were identified. The authors looked at both microbiologic and clinical outcomes; the most important were short-term and long-term clinical cures and adverse effects. The authors included studies of symptomatic women with available culture results, and they combined different durations of therapy for a given antibiotic into a single arm of the network meta-analysis. The short-term and long-term clinical cure rates were not significantly different among trimethoprim-sulfamethoxazole, norfloxacin, nitrofurantoin, and gatifloxacin; amoxicillin-clavulanate, however, was less effective. Ciprofloxacin and gatifloxacin were somewhat more effective in the short term. Harms were similar among the drugs.

Mark H. Ebell, MD, MS
Associate Professor
University of Georgia
Athens, GA

No Association Seen Between Standard-Dose NSAIDs and Progression of Moderate CKD

Clinical question: Should patients with chronic kidney disease entirely avoid nonsteroidal anti-inflammatory drugs?

Bottom line: Low or moderate doses of nonsteroidal anti-inflammatory drugs (NSAIDs) appear to be safe for patients with moderate chronic kidney disease (CKD; estimated glomerular filtration rate = 30 mL/min to 90 mL/min). High-dose NSAIDs should be avoided. Given the limitations of this evidence -- which was based on data from 7 observational studies rather than from randomized controlled trials -- caution is still prudent, and the lowest possible dose and duration should be advised. On the other hand, for patients with severe osteoarthritis, careful use of NSAIDs may be worth the small risk of progression of their CKD. (LOE = 2a)

Reference: Nderitu P, Doos L, Jones PW, Davies SJ, Kadam UT. Non-steroidal anti-inflammatory drugs and chronic kidney disease progression: a systematic review. Fam Pract 2013;30(3):247-255.

Study design: Systematic review

Funding source: Foundation

Setting: Various (meta-analysis)

Synopsis: Although patients with CKD are advised to avoid NSAIDs, the strength of evidence for this advice is uncertain. The authors of this systematic review carefully searched the literature and identified 5 cohort studies, 1 cross-sectional study, and 1 case-control study that addressed this question. The number of participants ranged from 801 to more than 1.5 million, with mean ages of participants between 45 years and 76 years. Progression of CKD was defined as an estimated glomerular filtration rate (eGFR) decrease of more than 15 mL per minute per 1.73 m2. Among patients with stage 2-3 CKD (eGFR between 30 mL/min and 90 mL/min), use of standard dose NSAIDs was not associated with an increased risk of progression of CKD. There was a modest association between high-dose NSAIDs and progression (relative risk = 1.26; 95% CI, 1.06 - 1.50). No association was seen with moderate dose NSAIDs (odds ratio = 0.96; 0.86 - 1.07), although the definition of moderate versus high-dose was not clearly stated by the authors. The 3 cohort studies that informed this conclusion included more than 55,000 patients.

Mark H. Ebell, MD, MS
Associate Professor
University of Georgia
Athens, GA

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