Urine culture doubtful in determining etiology of diffuse symptoms among elderly individuals: a cross-sectional study of 32 nursing homes

Table 1 Odds ratios and probabilities that findings of Escherichia coli in the urine¹ are associated with symptoms.

		Statistical correlation between bacteriuria and presence of symptom		Probability (%) for positive/negative culture to rule in/rule out that symptom is associated with bacterial finding
Symptoms	Prevalence²	Odds ratio (95% CI)	p-value	Positive/negative etiologic predictive value³
Restlessness	9.1%	1.4 (0.76-2.6)	0.28	34 (0-72)/99 (94-100)
Fatigue	12%	1.7 (0.99-2.9)	0.057	40 (0-73)/98 (94-100)
Confusion	7.5%	1.8 (0.96-3.6)	0.067	46 (0-79)/98 (92-100)
Aggressiveness	4.3%	2.3 (0.96-5.6)	0.063	44 (0-82)/98 (90-100)
Not being herself/himself	2.3%	4,4 (1.5-13)	0.0080	79 (0-98)/90 (50-100)
Dysuria	1.8%	1.6 (0.47-5.7)	0.44	46 (0-90)/98 (82-100)
Urgency	5.5%	1.3 (0.58-2.9)	0.52	17 (0-70)/99 (95-100)
Fever	0.31%	0 (0-∞)	0.97	---⁴

¹Escherichia coli was found in the urine in 143 of 651 urine samples.
²Appearance or increase of symptom or signs within the last three months in the studied population. All patients with fever acquired this within the last week.
³Etiologic predictive value (EPV) is a statistical method used to evaluate the clinical usefulness of dichotomous diagnostic tests. It estimates predictive values when there is no proper gold standard for comparison. EPVs are presented in this table with 95% confidence interval within parenthesis. To calculate the EPV the sensitivity of a urinary culture to detect presence of bacteriuria was estimated at 90%.
⁴The proportion of positive tests among individuals without the specified symptom or sign exceeds the proportion of positive tests among individuals with the specified symptom or sign. EPV cannot be calculated in these circumstances.

ISSN: 2731-4553