Clinical features to identify urinary tract infection in nursing home residents: a cohort study.

Objectives: To identify clinical features associated with bacteriuria plus pyuria in noncatheterized nursing home residents with clinically suspected urinary tract infection (UTI).

Design: Prospective, observational cohort study from 2005 to 2007.

Setting: Five New Haven, Connecticut area nursing homes.

Participants: Five hundred fifty-one nursing home residents each followed for 1 year for the development of clinically suspected UTI.

Measurements: The combined outcome of bacteriuria (>100,000 colony forming units from urine culture) plus pyuria (>10 white blood cells from urinalysis).

Results: After 178,914 person-days of follow-up, 228 participants had 399 episodes of clinically suspected UTI with a urinalysis and urine culture performed; 147 episodes (36.8%) had bacteriuria plus pyuria. The clinical features associated with bacteriuria plus pyuria were dysuria (relative risk (RR)=1.58, 95% confidence interval (CI)=1.10-2.03), change in character of urine (RR=1.42, 95% CI=1.07-1.79), and change in mental status (RR=1.38, 95% CI=1.03-1.74).

Conclusion: Dysuria, change in character of urine, and change in mental status were significantly associated with the combined outcome of bacteriuria plus pyuria. Absence of these clinical features identified residents at low risk of having bacteriuria plus pyuria (25.5%), whereas presence of dysuria plus one or both of the other clinical features identified residents at high risk of having bacteriuria plus pyuria (63.2%). Diagnostic uncertainty still remains for the vast majority of residents who meet only one clinical feature. If validated in future cohorts, these clinical features with bacteriuria plus pyuria may serve as an evidence-based clinical definition of UTI to assist in management decisions.