[Clinical presentation and performance of urine dipstick for diagnosis of urinary infection in geriatric population]

Abstract

Background: Urinary tract infections (UTI) are the second cause of community-acquired bacterial infections in the elderly. Distinguishing symptomatic UTI from asymptomatic bacteriuria is problematic, as older adults are less likely to present with localized urinary symptoms. We evaluated characteristics of patients presenting UTI among elderly with sepsis. Moreover, we aimed to evaluate the sensibility and specificity of urine dipstick tests in the diagnosis of UTI in geriatric population.

Patients and method: We led a prospective, monocentric, observational study between April 2017 and January 2018. We included patients hospitalized in geriatric wards, who were prescribed urine culture for UTI symptoms or/and infection without primary sites for which a urine culture was prescribed. Dipstick urinalyses were performed for all patients. Clinical and biological characteristics of all patients were compared according to the final diagnosis of UTI. Moreover, results of dipstick tests were evaluated for the diagnosis of UTI in this population.

Results: Among 165 patients, 67 (40.6 %) had a UTI and 98 (59.4 %) had another diagnosis. These two groups were comparable for age and daily-living activities. In the UTI group, the proportion of women was higher than in the other group (P<0.05), and mean MMSE score was lower (P<0.05). Positive urine dipstick test for leukocytes and/or nitrites had high sensitivity (92 %), but low specificity (50 %). Negative predictive value of this test was high (91 %).

Conclusion: For suspicion of UTI among elderly, few criteria are specific. Negative dipstick tests can suggest an absence of UTI due to its high negative predictive value.

Keywords: Bandelette urinaire; Dipstick test; Dépistage; ECBU; Geriatric; Gériatrie; Infection urinaire; Screening; Urinary tract infection; Urine culture.