Nursing home residents with suspected urinary tract infections: a diagnostic accuracy study

Background Urinary tract infections (UTIs) are one of the most common infections in nursing homes (NHs). A high error rate of a UTI diagnosis based solely on clinical criteria is to be expected in older persons as they often present infections in an atypical way. A study was set up to assess the diagnostic value of signs/symptoms and urine dipstick testing in identifying UTIs in NH residents and to explore whether C-reactive protein (CRP) measured by point-of-care testing (POCT) can help in the diagnosis. Methods During a three month prospective multicentre study, urine sampling for culture, POCT CRP and urinary dipstick testing were performed in each NH resident with a suspected UTI. UTIs were defined according to Stone et al., i.e. criteria based upon the presence of a set of signs/symptoms and a positive urine culture. Results Eleven NHs and 1 263 residents participated. Sixteen out of 137 recorded UTI suspicions were confirmed. Acute dysuria (positive likelihood ratio (LR +): 7.56, 95% confidence interval (CI): 3.94-14.5) and acute suprapubic pain (LR + : 11.4, 95% CI: 3.58-35.9) were found to be significant predictors. The combined nitrite and leucocyte esterase urine dipstick test (one or both positive) had a 96.0% negative predictive value (95% CI: 80.5-99.3%). The sensitivity of a positive CRP test (>= 5 mg/L) was 60.0% (95% CI: 32.3-83.7%). Antimicrobials were prescribed in 60.2% of suspected but unconfirmed UTIs and in 92.3% of confirmed UTIs. Conclusions Using a stringent definition, only 11.7% of our suspicions were confirmed. Besides acute dysuria and suprapubic pain, we were not able to prove that any other clinical sign/symptom or POCT CPR adds useful information to the UTI diagnosis. We confirmed the findings of earlier research that urine dipstick tests are useful in ruling out UTIs and identified a potential overuse of antimicrobials in our NH population.

Automated summary

Urinary tract infections (UTIs) are common in nursing homes (NHs), but diagnosing them solely based on clinical criteria can lead to high error rates. This study evaluated the diagnostic value of signs/symptoms and urine dipstick testing in UTI diagnosis and found that apart from acute dysuria and suprapubic pain, other clinical indicators and POCT CPR did not provide useful information. Urine dipstick testing was useful in ruling out UTIs, but there may be overuse of antimicrobials in the NH population.