Table 1.

Relationship of QS with hospital size (number of beds) and HAI prevalence computed through Spearman correlation and regression model analysis. The correlation index [95% CI] is reported for the correlation analysis and QS Ratio and Risk Ratio [95% CI] for the regression models. Both analyses were performed on the whole dataset and after stratification by hospital size category (< 200, 200–500, ≥ 500 beds)

	Model: QS ~ Number of beds
	Correlation index [95%CI]	QS Ratio [95%CI]
Hospital size stratum (beds)
Small (<  200)	− 0.00047 [− 0.26; 0.26]	0.76 [0.41, 1.39]
Medium (200–500)	0.008 [− 0.27; 0.28]	0.95 [0.67, 1.35]
Large (≥ 500)	0.37 [− 0.038; 0.67]	1.07 [0.88, 1.3]
All	0.02 [− 0.15; 0.19]	1.02 [0.96, 1.07]
	Model: HAI Prevalence ~ QS
	Correlation index [95%CI]	Risk Ratio [95%CI]
Hospital size stratum (beds)
Small (<  200)	0.0025 [− 0.25; 0.26]	0.91 [0.69, 1.13]
Medium (200–500)	− 0.34 [− 0.56; − 0.071]	0.84 [0.72, 0.97]
Large (≥ 500)	− 0.067 [− 0.46; 0.35]	0.98 [0.86, 1.09]
All	−0.12 [− 0.28; 0.054]	0.93 [0.86, 1.01]