Risk factors for poor prognosis in outpatients with urinary tract infection: a systematic review and meta-analysis

Peter Kurotschka, Felix Kannapin, Andreas Klug, Maria Chiara Bassi, Ildikó Gágyor, Mark H. Ebell

Keywords: Urinary Tract Infections; Prognostic factors; Outpatients; Primary Care; Systematic Review; Meta-Analysis

Background:

Observational studies identified several risk factors of poor prognosis in outpatients with urinary tract infection (UTI). These findings have never been systematically reviewed.

Research questions:

Which are the risk factors for poor prognosis in adult outpatients with UTI?

Method:

We searched Medline, Embase, Scopus, Cinahl, and Web of Science through November 2023, and searched citations of included studies. In parallel, two reviewers screened all records, abstracted study characteristics, risk factor and outcome data, and assessed risk of bias. We grouped outcomes into two categories of increasing severity: reconsultation and hospital admission. For risk factors reported by three or more studies, we performed random–effects meta-analysis of relative risks (univariate data) and adjusted odds ratios (aORs, multivariate data). We assessed heterogeneity visually and using the I2 statistic.

Results:

We included 36 studies with 1,948,814 adults aged 32 to 77 diagnosed with cystitis or pyelonephritis (PN). The only independent predictor of the outcome reconsultation was older age: the likelihood of experiencing this outcome for every additional 10 years of age increases by 18% (aOR 1.18). Independent predictors for hospital admission include age > 64 (aOR 3.51), male sex (aOR 1.41), and diabetes (aOR 1.34) for both patients with cystitis and with PN. Increased procalcitonin (PCT, aOR 5.12), low systolic blood pressure (aOR 3.29), fever > 38°C (aOR 2.08), C-reactive protein (aOR 1.62), and serum creatinine > 1.1 mg/dl (aOR 1.56) were also significantly associated with hospital admission in patients with PN.

Conclusions:

This is the first meta-analysis assessing risk factors for adverse outcomes in outpatients with UTI, either with acute cystitis or PN. We focused on clinical features, patient characteristics, and tests that are often available in the primary care setting. Until more evidence on prognosis of patients with UTI is available, clinical guidelines should take these risk factors into account when defining populations at risk of deterioration.

Points for discussion:

Do guidelines in your country / region identify patients at higher risk of poor prognosis?

How do you manage patients at risk of poor prognosis?

Are primary care databases with risk/prognostic factor and outcome data available for analysis in your country?

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